Merge remote-tracking branch 'origin/main' into web-host-bridge

shape.connect glues to a shape inside a group, and the connector follows it

.github/workflows/release.yml

@@ -45,3 +45,4 @@ jobs:
       AZURE_SIGNING_ENDPOINT: ${{ secrets.AZURE_SIGNING_ENDPOINT }}
       AZURE_SIGNING_ACCOUNT: ${{ secrets.AZURE_SIGNING_ACCOUNT }}
       AZURE_CERT_PROFILE: ${{ secrets.AZURE_CERT_PROFILE }}
+      LINUX_SIGNING_KEY: ${{ secrets.LINUX_SIGNING_KEY }}

Cargo.lock

@@ -1275,6 +1275,7 @@ dependencies = [
  "deckcraft-render",
  "deckcraft-text",
  "egui",
+ "egui_extras",
  "egui_kittest",
  "log",
  "serde",
@@ -1520,6 +1521,19 @@ dependencies = [
  "winit",
 ]
 
+[[package]]
+name = "egui_extras"
+version = "0.37.0"
+source = "git+https://github.com/storytold/egui.git?rev=6d518fc799681571963842f95b55a6b68431b15a#6d518fc799681571963842f95b55a6b68431b15a"
+dependencies = [
+ "ahash",
+ "egui",
+ "enum-map",
+ "itertools",
+ "log",
+ "profiling",
+]
+
 [[package]]
 name = "egui_glow"
 version = "0.37.0"
@@ -1587,6 +1601,26 @@ version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "66b7e2430c6dff6a955451e2cfc438f09cea1965a9d6f87f7e3b90decc014099"
 
+[[package]]
+name = "enum-map"
+version = "3.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d4532960034c15ba2f55e9eee631040ecc473c32e6c4b200828c759840f13a06"
+dependencies = [
+ "enum-map-derive",
+]
+
+[[package]]
+name = "enum-map-derive"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7127272f64b3e098f7d81f350d672081b879bff896d219c42370dc858b1af9ff"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 3.0.6",
+]
+
 [[package]]
 name = "enumflags2"
 version = "0.7.12"
@@ -3487,7 +3521,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7d8fae84b431384b68627d0f9b3b1245fcf9f46f6c0e3dc902e9dce64edd1967"
 dependencies = [
  "libc",
- "windows-sys 0.45.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -6511,11 +6545,6 @@ name = "egui_demo_lib"
 version = "0.37.0"
 source = "git+https://github.com/storytold/egui.git?rev=6d518fc799681571963842f95b55a6b68431b15a#6d518fc799681571963842f95b55a6b68431b15a"
 
-[[patch.unused]]
-name = "egui_extras"
-version = "0.37.0"
-source = "git+https://github.com/storytold/egui.git?rev=6d518fc799681571963842f95b55a6b68431b15a#6d518fc799681571963842f95b55a6b68431b15a"
-
 [[patch.unused]]
 name = "egui_inspection"
 version = "0.37.0"

ROADMAP.md

@@ -2,6 +2,9 @@
 
 **Stage: alpha** · next: beta, ~20 points and ~120–210 h away
 
+> **Last reviewed:** 2026-11-04 · **Last updated:** 2026-11-04 · **Change:** trivial (Ogg Opus recovery includes trailing packets without granules in its reported duration; parity scores unchanged) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
+> **Last reviewed:** 2026-11-02 · **Last updated:** 2026-11-03 · **Change:** trivial (progress log: web `?host=parent` bridge opens and saves through a same-origin framing page; scores unchanged) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
+
 > **Last reviewed:** 2026-11-02 · **Last updated:** 2026-11-03 · **Change:** trivial (community PR wave 10: PPTX and native saves keep table cell centred anchoring, text overflow, compatible line spacing, normalised character height, Thai distributed alignment, RTL table direction, alternate run language and reflection transforms; imported effects placed by parent time-node delays; Reuse Slides fits the destination size and brings custom table styles; deleted slides leave custom shows; merged shapes drop their animations; Compress Pictures measures grouped pictures at displayed size; parity scores unchanged) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
 > **Last reviewed:** 2026-11-02 · **Last updated:** 2026-11-02 · **Change:** trivial (File › About replaces Account; product links, credits and appearance retained; parity scores unchanged) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
 > **Last reviewed:** 2026-10-14 · **Last updated:** 2026-11-01 · **Change:** trivial (locked No Fill and no-outline click-through regression coverage added; No Fill hit-testing follows resolved fill instead of the presence of a style (#1621); scores unchanged) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
@@ -150,6 +153,8 @@ app's JSON control channel (`deckcraft --control PORT`).
 
 | Date | What landed |
 |---|---|
+| 2026-11-04 | Ogg Opus recovery keeps trailing packets without granules in the total duration, matching their recovered positions; valid end trimming stays covered |
+| 2026-11-03 | Web: the `?host=parent` bridge (as in GridCraft, WordCraft and PdfCraft) lets a same-origin page that frames DeckCraft send a presentation and store its saves; Save writes an opened .pptx back as .pptx under its own name, as on the desktop |
 | 2026-11-02 | Native and PPTX saves retain optional table right-to-left direction, including explicit false and omission; two-save round-trip tests keep labeled columns in order |
 | 2026-11-02 | Text runs preserve alternate-language metadata independently from the main language through native and PPTX saves |
 | 2026-11-02 | Picture compression measures displayed dimensions through nested group transforms; checklist score unchanged |
@@ -330,8 +335,10 @@ app's JSON control channel (`deckcraft --control PORT`).
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-11-04 | trivial | Ogg Opus recovery duration includes its recovered tail; parity scores unchanged |
 | 2026-11-02 | trivial | Progress log: run alternate-language metadata round-trips through native and PPTX formats; product parity scores unchanged |
 | 2026-11-03 | trivial | Reuse Slides brings referenced custom table styles along; scores unchanged |
+| 2026-11-03 | trivial | Progress log: web `?host=parent` bridge to a framing page; scores unchanged |
 | 2026-11-02 | trivial | File › About replaces Account; product links, credits and appearance retained |
 | 2026-11-02 | trivial | Progress log: tiled picture fills keep their size in scaled groups. Scores and milestone names unchanged |
 | 2026-10-31 | trivial | No Fill hit-testing follows resolved fill instead of the presence of a style (#1621); scores unchanged |

apps/deckcraft-web/Cargo.toml

@@ -27,4 +27,4 @@ rfd = { workspace = true }
 wasm-bindgen = "0.2"
 wasm-bindgen-futures = "0.4"
 js-sys = "0.3"
-web-sys = { version = "0.3", features = ["Window", "Document", "Element", "HtmlElement", "HtmlCanvasElement", "HtmlAnchorElement", "Blob", "BlobPropertyBag", "Url", "Location", "CssStyleDeclaration", "MessageEvent", "Event", "EventTarget"] }
+web-sys = { version = "0.3", features = ["Window", "Document", "Element", "HtmlElement", "HtmlCanvasElement", "HtmlAnchorElement", "Blob", "BlobPropertyBag", "Url", "Location", "CssStyleDeclaration", "MessageEvent", "Event", "EventTarget", "UrlSearchParams"] }

apps/deckcraft-web/src/host.rs

@@ -0,0 +1,192 @@
+//! The `postMessage` bridge to a same-origin parent page (`?host=parent`), for pages that embed
+//! DeckCraft in an `<iframe>` and keep its files (a Nextcloud app, a personal file server). The
+//! same messages as GridCraft's, WordCraft's and PdfCraft's bridges; each is a plain object with a
+//! `type`:
+//!
+//! - `deckcraft:ready` (to the parent): `{ version }`, sent once the app is running and
+//!   listening; send a file now.
+//! - `deckcraft:open` (from the parent): `{ name, bytes }`, bytes an `ArrayBuffer` or
+//!   `Uint8Array`, name a bare file name. It opens like a file picked with File › Open on the
+//!   desktop: a presentation sent with its name (.pptx, .potx, .ppsx, .deckcraft) has that name
+//!   as its file, so Save goes back to it; an outline (.txt, .md, .rtf), a file without a name and
+//!   a damaged file open untitled.
+//! - `deckcraft:save` (to the parent): `{ name, saveAs, bytes }` (a transferred `ArrayBuffer`) for
+//!   every file DeckCraft would otherwise download. The parent stores it and reports failures
+//!   itself. `saveAs` says whether the file becomes the presentation's file:
+//!   - Save: `false`. It writes the opened file under its own name and format (a .pptx stays a
+//!     .pptx), as the desktop app does. A name the parent never sent (an untitled presentation, an
+//!     outline, a file sent without a name, a repaired copy of a damaged file, a file the user
+//!     picked or dropped) is a new file: `true`, as for Save As, named `<title>.deckcraft` as
+//!     Save suggests on the desktop.
+//!   - Save As (File › Save As as .pptx or .deckcraft, Ctrl+Shift+S): `true`. The presentation is
+//!     now that file; the next Save sends its name with `false`.
+//!   - Export (PDF, pictures, outline, GIF, handouts, a Save As type that isn't a presentation)
+//!     and Print: `false`. They are copies; the presentation's file stays the same.
+//! - `deckcraft:dirty` (to the parent): `{ dirty }` whenever unsaved changes appear or go away.
+//! - `deckcraft:failed` (to the parent): `{ error }` when the app couldn't start.
+//!
+//! Only the parent window on the page's own origin is heard or answered. In host mode the app
+//! starts with an empty presentation instead of the sample, which gives way to the first file the
+//! parent sends; the parent guards leaving the page, and `?author=` names the user for comments.
+
+use std::cell::{Cell, RefCell};
+use std::rc::Rc;
+
+use deckcraft_ui_egui::{Services, SlideApp};
+use wasm_bindgen::JsCast as _;
+use wasm_bindgen::JsValue;
+use wasm_bindgen::closure::Closure;
+
+/// The longest user name taken from `?author=` (the preferences' own limit).
+const MAX_AUTHOR_CHARS: usize = 256;
+
+#[derive(Clone)]
+pub struct Bridge {
+    window: web_sys::Window,
+    parent: web_sys::Window,
+    origin: String,
+    /// Files the parent sent (the name, if it sent one), waiting for the next frame.
+    opened: Rc<RefCell<Vec<(Option<String>, Vec<u8>)>>>,
+    /// The unsaved-changes state last reported to the parent.
+    reported: Rc<Cell<Option<bool>>>,
+}
+
+impl Bridge {
+    /// `None` when the page isn't framed (there is no parent to talk to), or when the parent is
+    /// on another origin: messages only go to this origin, so the browser would drop every save
+    /// without an error while the presentation showed as saved.
+    pub fn new() -> Option<Self> {
+        let window = web_sys::window()?;
+        let parent = window.parent().ok().flatten()?;
+        if js_sys::Object::is(&parent, &window) {
+            return None;
+        }
+        let origin = window.location().origin().ok()?;
+        // An opaque origin (a `file://` page in some browsers) can't be a `postMessage` target.
+        if origin == "null" {
+            return None;
+        }
+        // Reading another origin's location throws, which is `None` too.
+        if parent.location().origin().ok()? != origin {
+            return None;
+        }
+        Some(Self { window, parent, origin, opened: Rc::default(), reported: Rc::default() })
+    }
+
+    /// Hand saved and exported files to the parent instead of downloading them, and hear the
+    /// files it sends.
+    pub fn connect(&self, services: &mut Services, ctx: egui::Context) {
+        self.listen(ctx);
+        let bridge = self.clone();
+        services.host_save = Some(Box::new(move |name: &str, bytes: &[u8], save_as: bool| bridge.post_save(name, bytes, save_as)));
+        // Exports and Print are copies.
+        let bridge = self.clone();
+        services.download = Some(Box::new(move |name: &str, bytes: &[u8]| {
+            if let Err(e) = bridge.post_save(name, bytes, false) {
+                log::error!("couldn't hand {name} to the page: {e}");
+            }
+        }));
+    }
+
+    /// `?author=`: the host's name for the user signs new comments.
+    pub fn set_author(app: &mut SlideApp, author: &str) {
+        let author: String = author.trim().chars().take(MAX_AUTHOR_CHARS).collect();
+        if !author.is_empty() {
+            app.session.prefs.author = author;
+        }
+    }
+
+    pub fn post_ready(&self) {
+        self.send(&[("type", "deckcraft:ready".into()), ("version", env!("CARGO_PKG_VERSION").into())]);
+    }
+
+    /// The app couldn't start (no WebGPU or WebGL2, for example): let the parent say so.
+    pub fn post_failed(&self, error: &str) {
+        self.send(&[("type", "deckcraft:failed".into()), ("error", error.into())]);
+    }
+
+    /// Before each frame: open the files the parent sent.
+    pub fn open_files(&self, app: &mut SlideApp) {
+        let opened = std::mem::take(&mut *self.opened.borrow_mut());
+        for (name, bytes) in opened {
+            app.open_from_host(name.as_deref(), &bytes);
+        }
+    }
+
+    /// After each frame: tell the parent when unsaved changes appear or go away.
+    pub fn report_dirty(&self, app: &SlideApp) {
+        let dirty = app.session.documents().iter().any(|d| d.is_dirty());
+        if self.reported.get() != Some(dirty) && self.send(&[("type", "deckcraft:dirty".into()), ("dirty", dirty.into())]) {
+            self.reported.set(Some(dirty));
+        }
+    }
+
+    fn post_save(&self, path: &str, bytes: &[u8], save_as: bool) -> Result<(), String> {
+        let name = std::path::Path::new(path).file_name().map(|n| n.to_string_lossy().to_string()).unwrap_or_else(|| path.to_string());
+        let buffer = js_sys::Uint8Array::from(bytes).buffer();
+        let message = message(&[
+            ("type", "deckcraft:save".into()),
+            ("name", name.as_str().into()),
+            ("saveAs", save_as.into()),
+            ("bytes", buffer.clone().into()),
+        ])
+        .ok_or_else(|| "couldn't build the message".to_string())?;
+        self.parent
+            .post_message_with_transfer(&message, &self.origin, &js_sys::Array::of1(&buffer))
+            .map_err(|e| e.as_string().unwrap_or_else(|| format!("{e:?}")))
+    }
+
+    /// Hear `deckcraft:open` from the parent and queue the file for the next frame.
+    fn listen(&self, ctx: egui::Context) {
+        let parent = self.parent.clone();
+        let origin = self.origin.clone();
+        let opened = self.opened.clone();
+        let on_message = Closure::<dyn FnMut(web_sys::MessageEvent)>::new(move |event: web_sys::MessageEvent| {
+            if event.origin() != origin || !event.source().is_some_and(|s| js_sys::Object::is(&s, &parent)) {
+                return;
+            }
+            let data = event.data();
+            if string(&data, "type").as_deref() != Some("deckcraft:open") {
+                return;
+            }
+            // No name is no file: the presentation opens untitled, never under an invented name.
+            let name = string(&data, "name").filter(|n| !n.trim().is_empty());
+            let Some(bytes) = bytes(&data) else { return };
+            opened.borrow_mut().push((name, bytes));
+            ctx.request_repaint();
+        });
+        if self.window.add_event_listener_with_callback("message", on_message.as_ref().unchecked_ref()).is_ok() {
+            // The listener lives as long as the page.
+            on_message.forget();
+        }
+    }
+
+    /// Post a message to the parent; false if it couldn't be sent.
+    fn send(&self, fields: &[(&str, JsValue)]) -> bool {
+        message(fields).is_some_and(|m| self.parent.post_message(&m, &self.origin).is_ok())
+    }
+}
+
+fn message(fields: &[(&str, JsValue)]) -> Option<js_sys::Object> {
+    let m = js_sys::Object::new();
+    for (key, value) in fields {
+        js_sys::Reflect::set(&m, &JsValue::from_str(key), value).ok()?;
+    }
+    Some(m)
+}
+
+fn string(data: &JsValue, key: &str) -> Option<String> {
+    js_sys::Reflect::get(data, &JsValue::from_str(key)).ok()?.as_string()
+}
+
+/// `bytes` as an `ArrayBuffer` or `Uint8Array`.
+fn bytes(data: &JsValue) -> Option<Vec<u8>> {
+    let bytes = js_sys::Reflect::get(data, &JsValue::from_str("bytes")).ok()?;
+    if let Some(array) = bytes.dyn_ref::<js_sys::Uint8Array>() {
+        Some(array.to_vec())
+    } else if bytes.is_instance_of::<js_sys::ArrayBuffer>() {
+        Some(js_sys::Uint8Array::new(&bytes).to_vec())
+    } else {
+        None
+    }
+}

apps/deckcraft-web/src/main.rs

@@ -9,15 +9,20 @@
 //! - File → Open and Insert → Pictures/Audio/Video use the browser file picker; bytes arrive
 //!   asynchronously through `Services::inbox`, applied to the document, slide and operation
 //!   that started the pick (a dismissed picker or a closed document drops the file);
-//! - Save and Export trigger a browser download;
+//! - Save and Export trigger a browser download (or go to the framing page with `?host=parent`);
 //! - dropped files are read asynchronously by `web::WebShell` and delivered through the inbox;
 //! - preferences are not persisted.
 //!
 //! URL query flags: `?webgl` forces the WebGL2 backend instead of WebGPU; `?blank` starts with an
 //! empty presentation instead of the sample deck; `?show` starts the slide show.
+//! `?host=parent` (inside an `<iframe>`) talks to a same-origin parent page instead: it sends the
+//! presentation to open and stores what DeckCraft saves (`host`), and `&author=` names the user
+//! for comments.
 #![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]
 #![forbid(unsafe_code)]
 
+#[cfg(target_arch = "wasm32")]
+mod host;
 #[cfg(target_arch = "wasm32")]
 mod presenter;
 #[cfg(target_arch = "wasm32")]

apps/deckcraft-web/src/presenter.rs

@@ -251,6 +251,9 @@ impl Popup {
                     if value.get("nextChanged").and_then(|v| v.as_bool()) == Some(false) {
                         data.next = previous.next.clone();
                     }
+                    if data.slides.is_none() {
+                        data.slides = previous.slides.clone();
+                    }
                 }
                 *target.borrow_mut() = Some(data);
                 *received.borrow_mut() = js_sys::Date::now();

apps/deckcraft-web/src/web.rs

@@ -24,8 +24,16 @@ pub fn start() {
             log::error!("missing <canvas id=\"{CANVAS_ID}\">");
             return;
         };
+        // `?host=parent`: a same-origin page framing DeckCraft opens presentations in it and
+        // stores what it saves (`host`). The presenter popup is never the framed page.
+        let host = query_param("host").as_deref() == Some("parent") && crate::presenter::token().is_none();
+        let bridge = if host { crate::host::Bridge::new() } else { None };
+        if host && bridge.is_none() {
+            log::warn!("?host=parent needs a framing page on the same origin; saves download instead");
+        }
+        let app_bridge = bridge.clone();
         let mut options = eframe::WebOptions::default();
-        if query().contains("webgl")
+        if query_has("webgl")
             && let eframe::egui_wgpu::WgpuSetup::CreateNew(create) = &mut options.wgpu_options.wgpu_setup
         {
             create.instance_descriptor.backends = eframe::wgpu::Backends::GL;
@@ -44,22 +52,42 @@ pub fn start() {
                         return Ok(Box::new(presenter) as Box<dyn eframe::App>);
                     }
                     let inbox: Inbox = Inbox::default();
-                    let mut app = SlideApp::new(Session::new(), services(inbox.clone(), cc.egui_ctx.clone()));
-                    let q = query();
-                    if !q.contains("blank") {
+                    let mut services = services(inbox.clone(), cc.egui_ctx.clone());
+                    if let Some(bridge) = &app_bridge {
+                        bridge.connect(&mut services, cc.egui_ctx.clone());
+                    }
+                    let mut app = SlideApp::new(Session::new(), services);
+                    // In host mode the parent sends the presentation to edit; no sample meanwhile.
+                    if app_bridge.is_some() {
+                        if let Err(e) = app.start_for_host() {
+                            log::error!("new presentation: {e}");
+                        }
+                    } else if !query_has("blank") {
                         if let Err(e) = deckcraft_engine::sample::open_sample(&mut app.session) {
                             log::error!("sample deck: {e}");
                         }
                     } else if let Err(e) = app.run("file.new", serde_json::json!({})) {
                         log::error!("new presentation: {e}");
                     }
-                    if q.contains("show") {
+                    if query_has("show") {
                         app.start_show(0, false);
                     }
-                    Ok(Box::new(WebShell { app, inbox }))
+                    if app_bridge.is_some()
+                        && let Some(author) = query_param("author")
+                    {
+                        crate::host::Bridge::set_author(&mut app, &author);
+                    }
+                    Ok(Box::new(WebShell { app, inbox, bridge: app_bridge }))
                 }),
             )
             .await;
+        // Ready only once the runner is up: starting can still fail after the app is made.
+        if let Some(bridge) = &bridge {
+            match &result {
+                Ok(()) => bridge.post_ready(),
+                Err(e) => bridge.post_failed(&format!("{e:?}")),
+            }
+        }
         if let Some(el) = document.get_element_by_id(LOADING_ID) {
             match result {
                 Ok(()) => el.remove(),
@@ -73,17 +101,36 @@ fn query() -> String {
     web_sys::window().and_then(|w| w.location().search().ok()).unwrap_or_default()
 }
 
+fn query_param(key: &str) -> Option<String> {
+    web_sys::UrlSearchParams::new_with_str(&query()).ok()?.get(key)
+}
+
+/// Whether the URL has the flag `key` (`?show`, `&blank=1`). A whole parameter, never a substring:
+/// `?author=` is free text.
+fn query_has(key: &str) -> bool {
+    web_sys::UrlSearchParams::new_with_str(&query()).is_ok_and(|q| q.has(key))
+}
+
 /// Wraps the app to read dropped files asynchronously (browsers can't read them synchronously)
 /// and feed them through the inbox.
 struct WebShell {
     app: SlideApp,
     inbox: Inbox,
+    /// The parent page that keeps the files (`?host=parent`).
+    bridge: Option<crate::host::Bridge>,
 }
 
 impl eframe::App for WebShell {
-    /// Delegate one eframe logic pass to the wrapped application.
+    /// Delegate one eframe logic pass to the wrapped application, opening the files the parent
+    /// page sent first and telling it about unsaved changes after.
     fn logic(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+        if let Some(bridge) = &self.bridge {
+            bridge.open_files(&mut self.app);
+        }
         self.app.logic(ctx);
+        if let Some(bridge) = &self.bridge {
+            bridge.report_dirty(&self.app);
+        }
         if self.app.show.is_none()
             && let Some(host) = self.app.services.presenter.as_mut()
         {

apps/deckcraft/src/logging.rs

@@ -148,19 +148,7 @@ pub fn rotate(dir: &Path) -> std::io::Result<(PathBuf, File)> {
 /// One formatted log line: `<timestamp> <LEVEL> [<thread>] <target>: <message>\n`.
 pub fn format_line(ts: &str, level: log::Level, thread: &str, target: &str, message: &str) -> String {
     let message = message.strip_suffix('\n').unwrap_or(message);
-    // Messages can embed document-controlled text (a part name, a relationship id): control
-    // characters other than tab are escaped and each continuation line is marked, so such text
-    // cannot start a line that looks like a record of its own.
-    let mut text = String::with_capacity(message.len());
-    for c in message.chars() {
-        match c {
-            '\n' => text.push_str("\n    | "),
-            '\t' => text.push(c),
-            c if c.is_control() => text.extend(c.escape_default()),
-            c => text.push(c),
-        }
-    }
-    format!("{ts} {level:<5} [{thread}] {target}: {text}\n")
+    format!("{ts} {level:<5} [{thread}] {target}: {message}\n")
 }
 
 /// Where formatted lines go besides standard error: kept in memory until a file is attached,
@@ -458,13 +446,8 @@ mod tests {
             ),
             "2026-10-08T07:59:17.728Z WARN  [main] deckcraft_pptx::opc: pptx: skipping oversized part ppt/media/image1.png\n"
         );
-        // A multi-line message keeps its lines, each continuation marked; the record still ends in
-        // exactly one newline.
-        assert!(format_line("t", log::Level::Error, "w", "x", "a\nb\n").ends_with("x: a\n    | b\n"));
-        // Injected line breaks and escape sequences cannot forge a record.
-        let line = format_line("t", log::Level::Warn, "w", "x", "part a\r\n2026 ERROR [m] y: forged\x1b[2J");
-        assert_eq!(line.matches('\n').count(), 2);
-        assert!(!line.contains('\r') && !line.contains('\x1b'));
+        // A multi-line message keeps its lines; the record still ends in exactly one newline.
+        assert!(format_line("t", log::Level::Error, "w", "x", "a\nb\n").ends_with("x: a\nb\n"));
     }
 
     #[test]

crates/av1/src/decoder.rs

@@ -425,6 +425,8 @@ impl Decoder {
 
     fn parse_obus(&mut self, data: &[u8], out: &mut Vec<(Output, usize, u32)>) -> Result<()> {
         let mut tu = 0usize;
+        // Repeated-frame outputs in `out`, counted as they are added rather than recounted per OBU.
+        let mut existing = out.iter().filter(|(o, _, _)| matches!(o, Output::Existing { .. })).count();
         let mut pos = 0;
         while pos < data.len() {
             let obu = parse_obu_unit(data, pos)?;
@@ -444,9 +446,10 @@ impl Decoder {
                 }
                 OBU_FRAME_HEADER_T | OBU_REDUNDANT_FRAME_HEADER_T | OBU_FRAME_T => {
                     if let Some(o) = self.frame_obu(&obu)? {
-                        if out.iter().filter(|(o, _, _)| matches!(o, Output::Existing { .. })).count() >= 32 {
+                        if existing >= 32 {
                             return Err(Error::Invalid("too many frame outputs in chunk"));
                         }
+                        existing += usize::from(matches!(o, Output::Existing { .. }));
                         out.push((o, tu, spatial_id));
                     }
                 }

crates/engine/src/cmd/file.rs

@@ -253,8 +253,15 @@ pub struct LoadedFile {
 #[cfg(not(target_arch = "wasm32"))]
 pub fn read_presentation_file(path: &str) -> Result<LoadedFile> {
     let bytes = crate::io::read_file(path).map_err(EngineError::Other)?;
-    let (doc, damaged) = open_checked(path, &bytes)?;
-    let native = deckcraft_format::sniff(&bytes) || deckcraft_pptx::sniff(&bytes);
+    loaded_file(path, &bytes)
+}
+
+/// Parse `bytes` as the presentation file `path`, as [`read_presentation_file`] does after
+/// reading it. The web host bridge uses it for a file its page sent, which then saves back to
+/// that name like a file opened on the desktop.
+pub fn loaded_file(path: &str, bytes: &[u8]) -> Result<LoadedFile> {
+    let (doc, damaged) = open_checked(path, bytes)?;
+    let native = deckcraft_format::sniff(bytes) || deckcraft_pptx::sniff(bytes);
     Ok(LoadedFile { path: path.to_string(), doc, native, damaged })
 }
 
@@ -397,6 +404,7 @@ pub fn pdf_options(p: &Value, count: usize) -> Result<deckcraft_pdf::PdfOptions>
 pub fn parse_slide_range(text: &str, count: usize) -> Result<Vec<usize>> {
     let invalid = || bad("file.export", format!("“{text}” isn't a valid slide range: use numbers and ranges such as 1-3, 5"));
     let mut out: Vec<usize> = vec![];
+    let mut seen: std::collections::HashSet<usize> = std::collections::HashSet::new();
     for part in text.split([',', ';']).map(str::trim).filter(|p| !p.is_empty()) {
         let (a, b) = match part.split_once('-') {
             Some((a, b)) => (a.trim(), b.trim()),
@@ -412,7 +420,7 @@ pub fn parse_slide_range(text: &str, count: usize) -> Result<Vec<usize>> {
             return Err(bad("file.export", format!("the presentation has {count} slides; “{part}” is outside them")));
         }
         for i in lo - 1..hi {
-            if !out.contains(&i) {
+            if seen.insert(i) {
                 out.push(i);
             }
         }
@@ -469,7 +477,10 @@ pub fn format_for_path(path: &str) -> &'static str {
     }
 }
 
-fn mark_saved(s: &mut Session, path: Option<String>) -> Result<()> {
+/// The active presentation is saved as it is now: no unsaved changes, and `path` (when given)
+/// becomes its file. `file.save` calls it after writing; the web host bridge calls it once the
+/// page has the bytes.
+pub fn mark_saved(s: &mut Session, path: Option<String>) -> Result<()> {
     let st = s.doc_mut()?;
     st.saved_doc = st.doc.clone();
     if path.is_some() {
@@ -776,6 +787,16 @@ mod tests {
 
     use super::{parse_slide_range, write_file};
 
+    #[test]
+    fn broad_and_repeated_slide_ranges_expand_once() {
+        // 200 copies of a 100,000-slide range: each index once, in order, without a scan per index.
+        let text = vec!["1-100000"; 200].join(",");
+        let v = parse_slide_range(&text, 100_000).unwrap();
+        assert_eq!(v.len(), 100_000);
+        assert!(v.windows(2).all(|w| w[0] < w[1]));
+        assert_eq!(parse_slide_range("3, 1-3, 2", 3).unwrap(), vec![2, 0, 1]);
+    }
+
     #[test]
     fn slide_range_rejects_plus_sign() {
         assert!(parse_slide_range("+2", 3).is_err());

crates/engine/src/cmd/review.rs

@@ -219,7 +219,7 @@ fn neighbour(s: &mut Session, p: &Value, forward: bool) -> Result<Value> {
     let cmd = if forward { "comment.next" } else { "comment.prev" };
     let (threads, slide, index) = {
         let st = s.doc()?;
-        (comment_threads(&st.doc), usize_param(p, "slide").unwrap_or(st.selection.slide), usize_param(p, "index"))
+        (comment_threads(&st.doc), usize_param(p, "slide").unwrap_or(st.selection.slide), super::opt_usize_param(p, "index", cmd)?)
     };
     if threads.is_empty() {
         return Err(bad(cmd, "no comments"));
@@ -367,7 +367,7 @@ fn spelling(s: &mut Session, p: &Value) -> Result<Value> {
             }
             out.push(v);
         }
-        let rep: Vec<usize> = crate::spell::repeated(para, &default).iter().map(|w| w.start).collect();
+        let rep: std::collections::HashSet<usize> = crate::spell::repeated(para, &default).iter().map(|w| w.start).collect();
         for w in crate::spell::paragraph_words(para, &default) {
             if ignore.contains(&w.text.to_lowercase()) || rep.contains(&w.start) {
                 continue;
@@ -421,23 +421,30 @@ fn add_to_dictionary(_s: &mut Session, p: &Value) -> Result<Value> {
 /// Replace whole-word `from` with `to` in `text`; how many were replaced.
 fn replace_word(text: &mut String, from: &str, to: &str, all: bool) -> usize {
     let is_word = |c: char| c.is_alphanumeric() || c == '\'' || c == '’';
-    let mut n = 0;
-    let mut at = 0;
+    // The result is built in one pass; the text is not edited in place for every match.
+    let mut out = String::new();
+    let (mut n, mut at, mut copied) = (0, 0, 0);
     while let Some(i) = text.get(at..).and_then(|t| t.find(from)).map(|i| i + at) {
         let end = i + from.len();
-        let before = text.get(..i).and_then(|t| t.chars().next_back()).is_some_and(is_word);
+        // The character before the match as the edited text would have it.
+        let before = text.get(copied..i).and_then(|t| t.chars().next_back()).or_else(|| out.chars().next_back()).is_some_and(is_word);
         let after = text.get(end..).and_then(|t| t.chars().next()).is_some_and(is_word);
         if before || after {
             at = end;
             continue;
         }
-        text.replace_range(i..end, to);
+        out.push_str(text.get(copied..i).unwrap_or_default());
+        out.push_str(to);
         n += 1;
-        at = i + to.len();
+        (at, copied) = (end, end);
         if !all {
             break;
         }
     }
+    if n > 0 {
+        out.push_str(text.get(copied..).unwrap_or_default());
+        *text = out;
+    }
     n
 }
 
@@ -764,6 +771,49 @@ fn end_compare(s: &mut Session, _: &Value) -> Result<Value> {
 
 #[cfg(test)]
 mod tests {
+    /// The replacement as it ran before: edited in place for every match.
+    fn replace_word_in_place(text: &mut String, from: &str, to: &str, all: bool) -> usize {
+        let is_word = |c: char| c.is_alphanumeric() || c == '\'' || c == '’';
+        let mut n = 0;
+        let mut at = 0;
+        while let Some(i) = text.get(at..).and_then(|t| t.find(from)).map(|i| i + at) {
+            let end = i + from.len();
+            let before = text.get(..i).and_then(|t| t.chars().next_back()).is_some_and(is_word);
+            let after = text.get(end..).and_then(|t| t.chars().next()).is_some_and(is_word);
+            if before || after {
+                at = end;
+                continue;
+            }
+            text.replace_range(i..end, to);
+            n += 1;
+            at = i + to.len();
+            if !all {
+                break;
+            }
+        }
+        n
+    }
+
+    #[test]
+    fn replace_word_matches_the_in_place_version() {
+        let cases = [
+            ("a a b a", "a", "x", true),
+            ("aa a. a", "a", "bb", true),
+            ("a-a -a-", "-", "ab", true),
+            ("foo. foo.", "foo.", "", true),
+            ("it's it", "it", "so", true),
+            ("x.x. x.", "x.", "y", true),
+            ("a a a", "a", "b", false),
+            ("none", "z", "q", true),
+            ("é é", "é", "e", true),
+        ];
+        for (text, from, to, all) in cases {
+            let (mut a, mut b) = (text.to_string(), text.to_string());
+            let (na, nb) = (replace_word(&mut a, from, to, all), replace_word_in_place(&mut b, from, to, all));
+            assert_eq!((na, a), (nb, b), "{text:?} {from:?} -> {to:?}");
+        }
+    }
+
     use super::*;
     use serde_json::json;
 
@@ -812,6 +862,40 @@ mod tests {
         assert_eq!(here["text"], "on first");
     }
 
+    #[test]
+    fn malformed_comment_navigation_index_does_not_change_selection() {
+        let mut s = Session::with_new();
+        s.execute("comment.add", &json!({"text": "first"})).unwrap();
+        s.execute("shape.insert", &json!({"preset": "rect", "rect": [10.0, 10.0, 40.0, 40.0]})).unwrap();
+        s.execute("slide.new", &json!({})).unwrap();
+        s.execute("comment.add", &json!({"text": "second"})).unwrap();
+        s.execute("slide.go", &json!({"index": 0})).unwrap();
+        let shape = s.doc().unwrap().doc.slides.first().and_then(|slide| slide.shapes.first()).map(|shape| shape.id).unwrap();
+        s.doc_mut().unwrap().selection.shapes = vec![shape];
+
+        for (command, value) in [
+            ("comment.next", json!(-1)),
+            ("comment.next", json!(1.5)),
+            ("comment.next", json!("bad")),
+            ("comment.prev", json!(-1)),
+            ("comment.prev", json!(1.5)),
+            ("comment.prev", json!("bad")),
+        ] {
+            let before = s.doc().unwrap().selection.clone();
+            let error = s.execute(command, &json!({"index": value})).unwrap_err();
+            assert!(error.to_string().contains("valid index"), "{command} {value}: {error}");
+            assert_eq!(s.doc().unwrap().selection, before, "{command} {value}");
+        }
+
+        let zero = s.execute("comment.next", &json!({"slide": 0, "index": 0})).unwrap();
+        assert_eq!(zero["slide"], 1);
+        assert_eq!(zero["index"], 0);
+        s.execute("slide.go", &json!({"index": 0})).unwrap();
+        let omitted = s.execute("comment.next", &json!({})).unwrap();
+        assert_eq!(omitted["slide"], 0);
+        assert_eq!(omitted["index"], 0);
+    }
+
     #[test]
     fn timestamps_are_iso_utc() {
         assert_eq!(iso_utc(0), "1970-01-01T00:00:00Z");

crates/engine/src/cmd/shape.rs

@@ -103,7 +103,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Shape Fill",
             ["Shape Format", "Shape Styles"],
             None,
-            "{color? | none?: true | background?: true (the slide background shows through; shapes and text boxes only) | gradient?: {stops: [[pos 0..1, color]], kind?: linear|radial|rectangular|path, angle?: deg (linear), focus?: [l, t, r, b] fractions (radial, rectangular and path: where the first stop sits), rotateWithShape?: bool} | picture?: base64 | pattern?: {preset, fg, bg} | transparency?: 0..1 | reset?: true, ids?}; pictureProps?: {tile?: bool, offsetX?, offsetY?: pt, scaleX?, scaleY?: 0..10, align?: tl|t|tr|l|ctr|r|bl|b|br, mirror?: none|x|y|xy, stretch?: [l, t, r, b] fractions, rotateWithShape?: bool} adjusts a picture fill; a group also formats its members",
+            "{color? | none?: true | background?: true (the slide background shows through; shapes and text boxes only) | gradient?: {stops: [[pos 0..1, color]], kind?: linear|radial|rectangular|path, angle?: deg (linear), focus?: [l, t, r, b] fractions (radial, rectangular and path: where the first stop sits), rotateWithShape?: bool (false keeps linear and radial gradients upright on the slide; rectangular and path gradients turn with the shape when drawn)} | picture?: base64 | pattern?: {preset, fg, bg} | transparency?: 0..1 | reset?: true, ids?}; pictureProps?: {tile?: bool, offsetX?, offsetY?: pt, scaleX?, scaleY?: 0..10, align?: tl|t|tr|l|ctr|r|bl|b|br, mirror?: none|x|y|xy, stretch?: [l, t, r, b] fractions, rotateWithShape?: bool} adjusts a picture fill; a group also formats its members",
             has_selection,
             fill
         ),

crates/engine/src/cmd/shape/appearance.rs

@@ -74,7 +74,8 @@ pub(super) fn change(s: &mut Session, p: &Value) -> Result<Value> {
 
 /// `{stops: [[pos 0–1, color], …], kind?: linear|radial|rectangular|path, angle?: deg (linear),
 /// focus?: [l, t, r, b] fractions (radial/rectangular/path: where the first stop sits),
-/// rotateWithShape?}`.
+/// rotateWithShape?}`. The renderer keeps only linear and radial gradients upright when
+/// `rotateWithShape` is false; rectangular and path gradients turn with the shape.
 pub(crate) fn gradient_param(v: &Value) -> Option<Gradient> {
     let stops: Vec<GradientStop> = v
         .get("stops")?

crates/engine/src/cmd/shape/freeform.rs

@@ -3,8 +3,9 @@ use super::{ColorRef, Fill, Geom, Line, NO_ID_SPACE, Result, Session, Value, bad
 pub(super) fn sites(s: &mut Session, p: &Value) -> Result<Value> {
     let id = id_param(p, "id", "shape.sites")?.ok_or_else(|| bad("shape.sites", "missing `id`"))?;
     let st = s.doc()?;
-    let sh = st.shape(id).ok_or_else(|| bad("shape.sites", "no such shape"))?;
-    Ok(json!(crate::connect::sites(&st.doc, &st.selection, sh).iter().map(|q| [q.x, q.y]).collect::<Vec<_>>()))
+    // In slide space, as shape.connect uses them, for a shape inside a group too.
+    let v = crate::connect::sites_of(&st.doc, &st.selection, st.shapes(), id).ok_or_else(|| bad("shape.sites", "no such shape"))?;
+    Ok(json!(v.iter().map(|q| [q.x, q.y]).collect::<Vec<_>>()))
 }
 
 pub(super) fn connect(s: &mut Session, p: &Value) -> Result<Value> {
@@ -12,8 +13,13 @@ pub(super) fn connect(s: &mut Session, p: &Value) -> Result<Value> {
         return Err(bad("shape.connect", "missing `from` / `to`"));
     };
     let st = s.doc()?;
-    let site_list = |id| st.shape(id).map(|sh| crate::connect::sites(&st.doc, &st.selection, sh)).unwrap_or_default();
-    let (a, b) = (site_list(from), site_list(to));
+    // Anywhere in the slide's tree: a shape inside a group takes a connector too (PowerPoint
+    // glues to grouped shapes), its sites where the group draws them.
+    let site_list = |id| {
+        crate::connect::sites_of(&st.doc, &st.selection, st.shapes(), id)
+            .ok_or_else(|| bad("shape.connect", format!("no shape {} on the current slide", id.0)))
+    };
+    let (a, b) = (site_list(from)?, site_list(to)?);
     if a.is_empty() || b.is_empty() {
         return Err(bad("shape.connect", "both shapes need connection sites (lines and groups have none)"));
     }
@@ -35,6 +41,11 @@ pub(super) fn connect(s: &mut Session, p: &Value) -> Result<Value> {
     };
     let (p0, p1) = (a[ia], b[ib]);
     let id = match id_param(p, "id", "shape.connect")? {
+        // The ends are in slide space and rerouting follows the slide's own connectors, so a line
+        // inside a group would be drawn in the group's space and never follow its shapes.
+        Some(id) if !st.shapes().iter().any(|sh| sh.id == id) && st.shape(id).is_some_and(|sh| sh.is_line()) => {
+            return Err(bad("shape.connect", "`id` names a line inside a group; ungroup it first, or leave `id` out for a new connector"));
+        }
         Some(id) => id,
         None => {
             let preset = str_param(p, "preset").unwrap_or("straightConnector1");

crates/engine/src/cmd/shape/size.rs

@@ -191,6 +191,13 @@ pub(super) fn rotate(s: &mut Session, p: &Value) -> Result<Value> {
 pub(super) fn flip(s: &mut Session, p: &Value) -> Result<Value> {
     let v = str_param(p, "axis").unwrap_or("horizontal").starts_with('v');
     edit_geometry(s, p, "shape.flip", |sh| {
+        // PowerPoint greys Flip out for a SmartArt graphic (SmartArt Design > Right to Left mirrors it),
+        // also inside a group: ungrouping would hand the flip to the graphic.
+        let mut graphic = false;
+        deckcraft_model::walk(std::slice::from_ref(&*sh), &mut |x, _| graphic |= x.diagram.is_some());
+        if graphic {
+            return Err(bad("shape.flip", "Flip is not available for a SmartArt graphic; use `smartArt.layout` to change how it is laid out"));
+        }
         if let Some(x) = sh.xfrm.as_mut() {
             if v {
                 x.flip_v = !x.flip_v;

crates/engine/src/cmd/slide.rs

@@ -408,8 +408,9 @@ fn select_slides(s: &mut Session, p: &Value) -> Result<Value> {
     };
     s.select(|doc, sel| {
         if add {
+            let mut have: std::collections::HashSet<_> = sel.slides.iter().copied().collect();
             for i in &ids {
-                if !sel.slides.contains(i) {
+                if have.insert(*i) {
                     sel.slides.push(*i);
                 }
             }

crates/engine/src/cmd/table.rs

@@ -253,9 +253,10 @@ fn cell_param(p: &Value, key: &str, cmd: &str) -> Result<Option<(usize, usize)>>
         None | Some(Value::Null) => return Ok(None),
         Some(v) => v,
     };
-    let idx = |i: usize| v.as_array().and_then(|a| a.get(i)).and_then(Value::as_u64).and_then(|x| usize::try_from(x).ok());
-    match (idx(0), idx(1)) {
-        (Some(r), Some(c)) => Ok(Some((r, c))),
+    // Exactly [row, col]: an entry with more is as malformed as one with less.
+    let idx = |x: &Value| x.as_u64().and_then(|x| usize::try_from(x).ok());
+    match v.as_array().map(Vec::as_slice) {
+        Some([r, c]) if let (Some(r), Some(c)) = (idx(r), idx(c)) => Ok(Some((r, c))),
         _ => Err(bad(cmd, format!("`{key}` is not a valid cell: {v}"))),
     }
 }
@@ -389,33 +390,54 @@ fn options(s: &mut Session, p: &Value) -> Result<Value> {
     })
 }
 
+/// At most this many `cells` in one table cell command.
+const MAX_CELLS: usize = 100_000;
+
 /// The cells a command acts on: `cells`, else the selected cell range, else the cell holding the
 /// caret, else every cell.
-fn target_cells(s: &Session, p: &Value) -> Result<impl Fn(&Table) -> Vec<(usize, usize)> + use<>> {
-    let cells: Option<Vec<(usize, usize)>> = p
-        .get("cells")
-        .and_then(Value::as_array)
-        .map(|a| a.iter().take(100_000).filter_map(|c| Some((c.get(0)?.as_u64()? as usize, c.get(1)?.as_u64()? as usize))).collect());
+fn target_cells(s: &Session, p: &Value, cmd: &str) -> Result<impl Fn(&Table) -> Result<Vec<(usize, usize)>> + use<>> {
+    // `cells` is a list of [row, col]: anything else, or an entry that is not one, is refused, never
+    // dropped or read as absent (which would act on the selection or the whole table).
+    let cells: Option<Vec<(usize, usize)>> = match p.get("cells") {
+        None | Some(Value::Null) => None,
+        Some(Value::Array(a)) if a.len() > MAX_CELLS => {
+            return Err(bad(cmd, format!("`cells` lists {} cells; at most {MAX_CELLS}", a.len())));
+        }
+        Some(Value::Array(a)) => Some(
+            a.iter()
+                .map(|c| {
+                    cell_param(&json!({ "cell": c }), "cell", cmd)?.ok_or_else(|| bad(cmd, format!("`cells` entry {c} is not a [row, col] cell")))
+                })
+                .collect::<Result<_>>()?,
+        ),
+        Some(v) => return Err(bad(cmd, format!("`cells` is a list of [row, col] cells, not {v}"))),
+    };
     let st = s.doc()?;
     // A selected range grows over the merged cells it touches; with only a caret, the caret's cell is used.
     let sel = st.selection.cells.map(|(_, a, b)| (a, b, true)).or_else(|| st.selection.text.as_ref().and_then(|t| t.cell).map(|c| (c, c, false)));
+    let cmd = cmd.to_string();
     Ok(move |t: &Table| match (&cells, sel) {
-        (Some(c), _) => c.clone(),
+        // Each listed cell must be in the table, so a command never reports success for a cell
+        // it could not edit.
+        (Some(c), _) => match c.iter().find(|(r, c)| *r >= t.n_rows() || *c >= t.n_cols()) {
+            Some((r, c)) => Err(bad(&cmd, format!("no cell [{r}, {c}]: the table has {} rows and {} columns", t.n_rows(), t.n_cols()))),
+            None => Ok(c.clone()),
+        },
         (None, Some((a, b, range))) => {
             let (a, b) = if range { cell_block(t, a, b) } else { (a, b) };
             // The selection can name cells outside the table; only walk the ones that exist.
             let (r1, c1) = (a.0.max(b.0).min(t.n_rows().saturating_sub(1)), a.1.max(b.1).min(t.n_cols().saturating_sub(1)));
-            (a.0.min(b.0)..=r1).flat_map(|r| (a.1.min(b.1)..=c1).map(move |c| (r, c))).collect()
+            Ok((a.0.min(b.0)..=r1).flat_map(|r| (a.1.min(b.1)..=c1).map(move |c| (r, c))).collect())
         }
-        _ => (0..t.n_rows()).flat_map(|r| (0..t.n_cols()).map(move |c| (r, c))).collect(),
+        _ => Ok((0..t.n_rows()).flat_map(|r| (0..t.n_cols()).map(move |c| (r, c))).collect()),
     })
 }
 
 fn cell_fill(s: &mut Session, p: &Value) -> Result<Value> {
     let fill = if bool_or(p, "none", false) { Some(deckcraft_model::Fill::None) } else { color_param(p, "color").map(deckcraft_model::Fill::solid) };
-    let targets = target_cells(s, p)?;
+    let targets = target_cells(s, p, "table.cellFill")?;
     with_table(s, p, "table.cellFill", move |t| {
-        for (r, c) in targets(t) {
+        for (r, c) in targets(t)? {
             if let Some(cell) = t.cell_mut(r, c) {
                 cell.fill.clone_from(&fill);
             }
@@ -447,9 +469,9 @@ fn borders(s: &mut Session, p: &Value) -> Result<Value> {
     }
     // "none" clears to no line, so the table style's own lines don't show through either.
     let line = if which == "none" { Line::none() } else { line };
-    let targets = target_cells(s, p)?;
+    let targets = target_cells(s, p, "table.borders")?;
     with_table(s, p, "table.borders", move |t| {
-        let list = targets(t);
+        let list = targets(t)?;
         let (Some(r0), Some(r1), Some(c0), Some(c1)) =
             (list.iter().map(|x| x.0).min(), list.iter().map(|x| x.0).max(), list.iter().map(|x| x.1).min(), list.iter().map(|x| x.1).max())
         else {
@@ -463,9 +485,9 @@ fn borders(s: &mut Session, p: &Value) -> Result<Value> {
             }
             let n = match side {
                 LEFT => c.checked_sub(1).map(|c| (r, c, RIGHT)),
-                RIGHT => (c + 1 < cols).then_some((r, c + 1, LEFT)),
+                RIGHT => c.checked_add(1).filter(|c| *c < cols).map(|c| (r, c, LEFT)),
                 TOP => r.checked_sub(1).map(|r| (r, c, BOTTOM)),
-                _ => (r + 1 < rows).then_some((r + 1, c, TOP)),
+                _ => r.checked_add(1).filter(|r| *r < rows).map(|r| (r, c, TOP)),
             };
             if let Some((r, c, side)) = n
                 && let Some(cell) = t.cell_mut(r, c)
@@ -523,9 +545,9 @@ fn cell_margins(s: &mut Session, p: &Value) -> Result<Value> {
     };
     let side = |k: &str, i: usize| f64_param(p, k).filter(|v| v.is_finite()).map_or(base[i], |v| v.clamp(0.0, 400.0));
     let m = [side("left", 0), side("right", 1), side("top", 2), side("bottom", 3)];
-    let targets = target_cells(s, p)?;
+    let targets = target_cells(s, p, "table.cellMargins")?;
     with_table(s, p, "table.cellMargins", move |t| {
-        for (r, c) in targets(t) {
+        for (r, c) in targets(t)? {
             if let Some(cell) = t.cell_mut(r, c) {
                 cell.margins = Some(m);
             }
@@ -560,9 +582,9 @@ fn cell_align(s: &mut Session, p: &Value) -> Result<Value> {
             o => return Err(bad("table.cellAlign", format!("unknown anchor {o:?}; one of top, middle, bottom"))),
         }),
     };
-    let targets = target_cells(s, p)?;
+    let targets = target_cells(s, p, "table.cellAlign")?;
     with_table(s, p, "table.cellAlign", move |t| {
-        for (r, c) in targets(t) {
+        for (r, c) in targets(t)? {
             if let Some(cell) = t.cell_mut(r, c) {
                 if anchor.is_some() {
                     cell.anchor = anchor;

crates/engine/src/compare.rs

@@ -121,9 +121,10 @@ pub fn diff(cur: &Presentation, rev: &Presentation, by_position: bool) -> Vec<Ch
     let cur_matched: HashSet<usize> = pairs.iter().map(|p| p.0).collect();
     let rev_matched: HashSet<usize> = pairs.iter().map(|p| p.1).collect();
     let mut out = vec![];
+    let mut media = Media::new(cur, rev);
     for (i, j) in &pairs {
         let (Some(a), Some(b)) = (cur.slides.get(*i), rev.slides.get(*j)) else { continue };
-        let details = slide_details(cur, a, rev, b);
+        let details = slide_details(cur, a, rev, b, &mut media);
         if !details.is_empty() {
             out.push(Change { kind: ChangeKind::Changed, slide: *i, number: i.saturating_add(1), only_in: None, revised: Some(*j), details });
         }
@@ -140,10 +141,18 @@ pub fn diff(cur: &Presentation, rev: &Presentation, by_position: bool) -> Vec<Ch
             });
         }
     }
+    // Each revised slide's open match (the first pair naming it).
+    let mut rev_to_cur: HashMap<usize, usize> = HashMap::new();
+    for p in &pairs {
+        rev_to_cur.entry(p.1).or_insert(p.0);
+    }
+    // After the open slide that matches the nearest matched revised slide before it.
+    let mut at = 0;
     for (j, s) in rev.slides.iter().enumerate() {
+        if let Some(i) = rev_to_cur.get(&j) {
+            at = i + 1;
+        }
         if !rev_matched.contains(&j) {
-            // After the open slide that matches the revised slide before it.
-            let at = (0..j).rev().find_map(|k| pairs.iter().find(|p| p.1 == k).map(|p| p.0 + 1)).unwrap_or(0);
             out.push(Change {
                 kind: ChangeKind::Inserted,
                 slide: at,
@@ -174,8 +183,34 @@ fn shape_label(s: &Shape) -> String {
     if s.name.trim().is_empty() { format!("Shape {}", s.id.0) } else { s.name.clone() }
 }
 
-fn media_bytes(p: &Presentation, id: MediaId) -> Option<&[u8]> {
-    p.media(id).map(|m| m.data.as_slice())
+/// Both decks' media bytes by id, and which picture pairs were already compared: a deck can
+/// show one picture many times, and its bytes are compared once per pair.
+struct Media<'a> {
+    cur: HashMap<MediaId, &'a [u8]>,
+    rev: HashMap<MediaId, &'a [u8]>,
+    same: HashMap<(MediaId, MediaId), bool>,
+}
+
+impl<'a> Media<'a> {
+    fn new(cur: &'a Presentation, rev: &'a Presentation) -> Self {
+        // The first item with an id wins, as in `Presentation::media`.
+        let index = |p: &'a Presentation| {
+            let mut m = HashMap::new();
+            for x in &p.media {
+                m.entry(x.id).or_insert(x.data.as_slice());
+            }
+            m
+        };
+        Media { cur: index(cur), rev: index(rev), same: HashMap::new() }
+    }
+    /// Whether the pictures (by media id, `None` for a shape that is not a picture) differ.
+    fn differ(&mut self, a: Option<MediaId>, b: Option<MediaId>) -> bool {
+        let (ba, bb) = (a.and_then(|x| self.cur.get(&x)), b.and_then(|y| self.rev.get(&y)));
+        match (a, b) {
+            (Some(x), Some(y)) if ba.is_some() && bb.is_some() => !*self.same.entry((x, y)).or_insert_with(|| ba == bb),
+            _ => ba.is_some() || bb.is_some(),
+        }
+    }
 }
 
 /// A shape without its ids (shape and media), for comparing across decks.
@@ -204,7 +239,7 @@ fn turn(ctx: Option<&Ctx>, s: &Shape) -> (f64, bool, bool) {
     drawn_box(ctx, s).map_or((0.0, false, false), |x| (x.rot, x.flip_h, x.flip_v))
 }
 
-fn shape_details(cp: &Presentation, ca: Option<&Ctx>, a: &Shape, rp: &Presentation, cb: Option<&Ctx>, b: &Shape, out: &mut Vec<String>) {
+fn shape_details(ca: Option<&Ctx>, a: &Shape, cb: Option<&Ctx>, b: &Shape, media: &mut Media, out: &mut Vec<String>) {
     let label = shape_label(b);
     let text = |s: &Shape| s.text.as_ref().map(|t| t.text()).unwrap_or_default();
     let mut what = vec![];
@@ -234,11 +269,11 @@ fn shape_details(cp: &Presentation, ca: Option<&Ctx>, a: &Shape, rp: &Presentati
     if a.fill != b.fill || a.line != b.line || a.style != b.style || a.effects != b.effects {
         what.push("formatting");
     }
-    let pic = |p: &Presentation, s: &Shape| match &s.kind {
-        ShapeKind::Picture { fill } => media_bytes(p, fill.media).map(|b| b.to_vec()),
+    let pic = |s: &Shape| match &s.kind {
+        ShapeKind::Picture { fill } => Some(fill.media),
         _ => None,
     };
-    if pic(cp, a) != pic(rp, b) {
+    if media.differ(pic(a), pic(b)) {
         what.push("picture");
     }
     // Anything the checks above do not cover (alt text, hidden, a link…) is reported too, also
@@ -265,21 +300,32 @@ fn shape_details(cp: &Presentation, ca: Option<&Ctx>, a: &Shape, rp: &Presentati
     }
 }
 
-fn slide_details(cp: &Presentation, a: &Slide, rp: &Presentation, b: &Slide) -> Vec<String> {
+fn slide_details(cp: &Presentation, a: &Slide, rp: &Presentation, b: &Slide, media: &mut Media) -> Vec<String> {
     let mut out = vec![];
     let mut used: HashSet<usize> = HashSet::new();
     let (ca, cb) = (Ctx::for_slide(cp, a), Ctx::for_slide(rp, b));
+    // The revised shapes by id (first wins) and by name (in order, with a cursor past used ones).
+    let mut by_id: HashMap<ShapeId, usize> = HashMap::new();
+    let mut by_name: HashMap<&str, (Vec<usize>, usize)> = HashMap::new();
+    for (k, x) in b.shapes.iter().enumerate() {
+        by_id.entry(x.id).or_insert(k);
+        if !x.name.is_empty() {
+            by_name.entry(x.name.as_str()).or_default().0.push(k);
+        }
+    }
     for sa in &a.shapes {
-        let k = b
-            .shapes
-            .iter()
-            .position(|x| x.id == sa.id)
-            .or_else(|| b.shapes.iter().enumerate().position(|(k, x)| !used.contains(&k) && x.name == sa.name && !x.name.is_empty()));
+        let k = by_id.get(&sa.id).copied().or_else(|| {
+            let (ks, next) = by_name.get_mut(sa.name.as_str())?;
+            while ks.get(*next).is_some_and(|k| used.contains(k)) {
+                *next += 1;
+            }
+            ks.get(*next).copied()
+        });
         match k {
             Some(k) if !used.contains(&k) => {
                 used.insert(k);
                 if let Some(sb) = b.shapes.get(k) {
-                    shape_details(cp, ca.as_ref(), sa, rp, cb.as_ref(), sb, &mut out);
+                    shape_details(ca.as_ref(), sa, cb.as_ref(), sb, media, &mut out);
                 }
             }
             _ => out.push(format!("{} deleted (only in the deck)", shape_label(sa))),
@@ -334,19 +380,34 @@ pub fn adopt(doc: &mut Presentation, rev: &Presentation, slide: &Slide, replacin
     let mut sl = slide.clone();
     // Media.
     let mut media_map: HashMap<MediaId, MediaId> = HashMap::new();
+    // Both decks' media by id (the first item with an id wins, as in `Presentation::media`),
+    // looked up once per reference instead of searched.
+    let mut rev_at: HashMap<MediaId, usize> = HashMap::new();
+    for (i, m) in rev.media.iter().enumerate() {
+        rev_at.entry(m.id).or_insert(i);
+    }
+    let mut doc_at: HashMap<MediaId, usize> = HashMap::new();
+    for (i, m) in doc.media.iter().enumerate() {
+        doc_at.entry(m.id).or_insert(i);
+    }
     for id in crate::media_refs::slide_media(&sl) {
-        let Some(m) = rev.media(id) else { continue };
-        match doc.media(id) {
+        let Some(m) = rev_at.get(&id).and_then(|&i| rev.media.get(i)) else { continue };
+        match doc_at.get(&id).and_then(|&i| doc.media.get(i)) {
             Some(x) if x.data == m.data => {}
             None => {
                 // Keeps the revision's id, so later ids must start past it.
+                doc_at.insert(id, doc.media.len());
                 doc.media.push(m.clone());
                 doc.next_id = doc.next_id.max(id.0);
             }
             Some(_) => {
+                let before = doc.media.len();
                 let new = doc
                     .add_media(&m.name, &m.content_type, m.data.as_ref().clone())
                     .ok_or_else(|| crate::cmd::bad("review.accept", crate::cmd::NO_ID_SPACE))?;
+                if doc.media.len() > before {
+                    doc_at.entry(new).or_insert(before);
+                }
                 media_map.insert(id, new);
             }
         }
@@ -519,6 +580,39 @@ mod tests {
         assert_eq!(s.doc().unwrap().doc.slides.len(), n, "comparing alone changes nothing");
     }
 
+    #[test]
+    fn many_inserted_slides_and_same_named_pictures_compare_by_index() {
+        use std::sync::Arc;
+
+        use deckcraft_model::style::PictureFill;
+        use deckcraft_model::{Shape, ShapeId, ShapeKind, SlideId, defaults};
+
+        // One slide of 3,000 pictures of one image, all named "Box"; the revision has the same
+        // pictures under other ids (matched by name, in order) and 3,000 slides inserted after it.
+        let mut cur = defaults::new_presentation(None);
+        let img = cur.add_media("a.png", "image/png", vec![7; 4096]).unwrap();
+        let mut rev = cur.clone();
+        let pic = |id: u32| Shape {
+            id: ShapeId(id),
+            name: "Box".into(),
+            xfrm: Some(deckcraft_model::Xfrm::new(10.0, 10.0, 50.0, 50.0)),
+            kind: ShapeKind::Picture { fill: PictureFill { media: img, ..Default::default() } },
+            ..Default::default()
+        };
+        Arc::make_mut(&mut cur.slides[0]).shapes = (0..3000).map(|k| pic(100_000 + k)).collect();
+        Arc::make_mut(&mut rev.slides[0]).shapes = (0..3000).map(|k| pic(200_000 + k)).collect();
+        let mut base = (*rev.slides[0]).clone();
+        base.shapes.clear();
+        for k in 0..3000 {
+            let mut s = base.clone();
+            s.id = SlideId(300_000 + k);
+            rev.slides.push(Arc::new(s));
+        }
+        let changes = super::diff(&cur, &rev, false);
+        assert_eq!(changes.len(), 3000, "only the inserted slides differ");
+        assert!(changes.iter().all(|c| c.kind == super::ChangeKind::Inserted && c.slide == 1));
+    }
+
     /// A deck with one slide: a table whose cell has a picture fill, a picture background and a
     /// transition sound. `tag` starts the bytes of each.
     fn media_deck(tag: &str) -> deckcraft_model::Presentation {

crates/engine/src/connect.rs

@@ -1,14 +1,21 @@
 //! Connectors glued to shapes: connection sites, snapping line ends to them, and rerouting attached
 //! connectors whenever the shapes they connect move, resize or rotate.
 
-use deckcraft_geom::{Point, Xfrm};
+use deckcraft_geom::{Affine, Point, Rect, Xfrm};
 use deckcraft_model::{Presentation, Shape, ShapeId, ShapeKind};
 
 use crate::Selection;
 use crate::cmd::xfrm_of;
 
-/// Connection sites of `s` in slide coordinates (index = site index stored on connectors).
+/// Connection sites of a top-level shape `s` in slide coordinates (index = site index stored on
+/// connectors). For a shape inside a group use [`sites_of`] or [`sites_in`].
 pub fn sites(doc: &Presentation, sel: &Selection, s: &Shape) -> Vec<Point> {
+    sites_in(doc, sel, s, Affine::IDENTITY)
+}
+
+/// Connection sites of `s` in slide coordinates, `to_abs` mapping the space its box lives in (the
+/// slide, or the child space of the groups around it) onto the slide.
+pub fn sites_in(doc: &Presentation, sel: &Selection, s: &Shape, to_abs: Affine) -> Vec<Point> {
     if s.is_line() || matches!(s.kind, ShapeKind::Group { .. } | ShapeKind::Ink { .. }) {
         return vec![];
     }
@@ -17,10 +24,42 @@ pub fn sites(doc: &Presentation, sel: &Selection, s: &Shape) -> Vec<Point> {
     if local.is_empty() {
         local = vec![Point::new(x.w / 2.0, 0.0), Point::new(0.0, x.h / 2.0), Point::new(x.w / 2.0, x.h), Point::new(x.w, x.h / 2.0)];
     }
-    let a = x.affine();
+    let a = to_abs * x.affine();
     local.into_iter().map(|p| a * p).collect()
 }
 
+/// The shape `id` anywhere in `shapes` (a group's member included) with the affine that maps the
+/// space its box lives in onto the slide: a connector glues to a grouped shape, as in PowerPoint,
+/// and its sites are where the group draws them.
+pub fn locate<'a>(doc: &Presentation, sel: &Selection, shapes: &'a [Shape], id: ShapeId) -> Option<(&'a Shape, Affine)> {
+    fn rec<'a>(doc: &Presentation, sel: &Selection, shapes: &'a [Shape], id: ShapeId, to_abs: Affine, depth: usize) -> Option<(&'a Shape, Affine)> {
+        if depth > 64 {
+            return None;
+        }
+        for s in shapes {
+            if s.id == id {
+                return Some((s, to_abs));
+            }
+            if let ShapeKind::Group { children, child } = &s.kind {
+                let x = xfrm_of(doc, sel, s);
+                let ch = Rect::new(child.x, child.y, child.x + child.w, child.y + child.h);
+                let nested = to_abs * deckcraft_geom::group_child_affine(&x, ch);
+                if let Some(f) = rec(doc, sel, children, id, nested, depth + 1) {
+                    return Some(f);
+                }
+            }
+        }
+        None
+    }
+    rec(doc, sel, shapes, id, Affine::IDENTITY, 0)
+}
+
+/// Connection sites of shape `id` anywhere in `shapes`, in slide coordinates; `None` when there is
+/// no such shape.
+pub fn sites_of(doc: &Presentation, sel: &Selection, shapes: &[Shape], id: ShapeId) -> Option<Vec<Point>> {
+    locate(doc, sel, shapes, id).map(|(s, a)| sites_in(doc, sel, s, a))
+}
+
 /// The nearest connection site within `radius` of `p` on any visible shape except `exclude`.
 pub fn nearest_site(
     doc: &Presentation,
@@ -68,8 +107,8 @@ pub fn reroute(doc: &mut Presentation, sel: &Selection) {
     let snapshot: Vec<Shape> = list.clone();
     let view = doc.clone();
     let site = |id: ShapeId, idx: u32| -> Option<Point> {
-        let s = snapshot.iter().find(|s| s.id == id)?;
-        let v = sites(&view, sel, s);
+        // Anywhere in the tree: a connector glued to a shape that is then grouped keeps following it.
+        let v = sites_of(&view, sel, &snapshot, id)?;
         v.get(idx as usize).or(v.first()).copied()
     };
     let mut updates: Vec<(usize, Xfrm, bool, bool)> = vec![];

crates/engine/src/io.rs

@@ -48,6 +48,8 @@ pub fn write_file(path: &str, bytes: &[u8]) -> Result<(), String> {
         // A short fixed-size name: appending to the target's name could exceed the file name limit.
         let tmp_name = format!(".deckcraft.{}.{}.saving", std::process::id(), COUNTER.fetch_add(1, Ordering::Relaxed));
         let tmp = target_path.with_file_name(tmp_name);
+        // The sibling must pass the same check: when `path` is the write root itself it lands outside.
+        crate::file_access::check_write(&tmp.to_string_lossy())?;
         match std::fs::OpenOptions::new().write(true).create_new(true).open(&tmp) {
             Ok(f) => break (tmp, f),
             Err(e) if e.kind() == std::io::ErrorKind::AlreadyExists && attempts < 16 => attempts += 1,
@@ -135,4 +137,16 @@ mod tests {
 
         let _ = std::fs::remove_file(&file);
     }
+
+    #[test]
+    fn write_file_to_the_write_root_itself_creates_no_sibling_outside_it() {
+        let base = std::env::temp_dir().join(format!("deckcraft_io_root_test_{}", std::process::id()));
+        let root = base.join("root");
+        std::fs::create_dir_all(&root).unwrap();
+        let roots = crate::file_access::AutomationRoots::new(&[], std::slice::from_ref(&root)).unwrap().unwrap();
+        let res = crate::file_access::confine(Some(&roots), || write_file(root.to_str().unwrap(), b"x"));
+        assert!(res.unwrap_err().contains("outside the write root"));
+        assert_eq!(std::fs::read_dir(&base).unwrap().count(), 1, "only the root is there");
+        let _ = std::fs::remove_dir_all(&base);
+    }
 }

crates/engine/src/spell.rs

@@ -700,15 +700,29 @@ pub struct Word {
     pub repeated: Option<usize>,
 }
 
+/// Longest language tag a word is checked in. BCP 47 tags in documents are a few bytes; a longer
+/// value from a file is no language we have a dictionary for, and copying it into every word of
+/// a paragraph would multiply it.
+const MAX_LANG_LEN: usize = 64;
+
 /// The words of `p`, each with its run's language (`lang` on the run, else `default`). Words
 /// with digits are skipped; apostrophes inside a word belong to it; hyphenated words are checked
-/// part by part.
+/// part by part. A language over [`MAX_LANG_LEN`] counts as none.
 pub fn paragraph_words(p: &deckcraft_model::Paragraph, default: &str) -> Vec<Word> {
     let mut chars: Vec<(char, usize)> = vec![];
     for (ri, r) in p.runs.iter().enumerate() {
         chars.extend(r.content().chars().map(|c| (c, ri)));
     }
-    let lang_of = |ri: usize| p.runs.get(ri).and_then(|r| r.props.lang.clone()).filter(|l| !l.is_empty()).unwrap_or_else(|| default.to_string());
+    let default = if default.len() > MAX_LANG_LEN { "" } else { default };
+    let lang_of = |ri: usize| {
+        p.runs
+            .get(ri)
+            .and_then(|r| r.props.lang.as_deref())
+            .filter(|l| !l.is_empty())
+            .map(|l| if l.len() > MAX_LANG_LEN { "" } else { l })
+            .unwrap_or(default)
+            .to_string()
+    };
     // Combining marks (decomposed accents) belong to the letter before them.
     let inside = |c: char| c.is_alphanumeric() || deckcraft_model::words::is_combining_mark(c) || c == '\'' || c == '’' || c == '-';
     let mut out = vec![];
@@ -791,15 +805,18 @@ pub fn misspelt(p: &deckcraft_model::Paragraph, default: &str, ignore: &[String]
         .chain(repeated(p, default))
         .collect::<Vec<_>>()
         .into_iter()
-        .fold(vec![], |mut v: Vec<Word>, w| {
+        .fold((vec![], HashMap::new()), |(mut v, mut at): (Vec<Word>, HashMap<usize, usize>), w| {
             // A repeated misspelt word is reported once, as repeated.
-            if let Some(i) = v.iter().position(|x| x.start == w.start) {
-                v[i] = w;
-            } else {
-                v.push(w);
+            match at.get(&w.start).and_then(|&i| v.get_mut(i)) {
+                Some(x) => *x = w,
+                None => {
+                    at.insert(w.start, v.len());
+                    v.push(w);
+                }
             }
-            v
+            (v, at)
         })
+        .0
 }
 
 /// Use `d` for `lang` from now on in this process (a dictionary the app loaded itself).
@@ -953,6 +970,23 @@ SFX D Y 1\nSFX D 0 ed/S .\n";
         assert_eq!(w, vec!["check", "done"]);
     }
 
+    #[test]
+    fn a_long_paragraph_with_a_huge_language_is_checked_in_linear_work() {
+        use deckcraft_model::{Paragraph, Run, RunProps};
+        // 100,000 copies of one word under a 1 MB language value: every word after the first is
+        // a repeat, and no word carries a copy of the value.
+        let lang = "x".repeat(1 << 20);
+        let p =
+            Paragraph { runs: vec![Run::with("the ".repeat(100_000), RunProps { lang: Some(lang), ..Default::default() })], ..Default::default() };
+        let words = paragraph_words(&p, "en-US");
+        assert_eq!(words.len(), 100_000);
+        assert!(words.iter().all(|w| w.lang.is_empty()));
+        let bad = misspelt(&p, "en-US", &[]);
+        assert_eq!(bad.len(), 99_999);
+        assert!(bad.iter().all(|w| w.repeated.is_some()));
+        assert!(paragraph_words(&Paragraph::new("word"), &"y".repeat(100)).iter().all(|w| w.lang.is_empty()));
+    }
+
     #[test]
     fn long_and_numeric_flags_and_latin1() {
         let d = Dictionary::parse(b"FLAG long\nSFX Aa Y 1\nSFX Aa 0 s .\n", b"1\ncat/Aa\n");

crates/engine/src/tests.rs

@@ -4321,6 +4321,9 @@ fn shape_fill_documents_each_gradient_key_and_kind() {
     let params = cmd::parse_params(find_command("shape.fill").unwrap().params).unwrap();
     let about = params.iter().find(|p| p.name == "gradient").unwrap().about;
     assert_eq!(cmd::param_keys(about).unwrap(), ["stops", "kind", "angle", "focus", "rotateWithShape"]);
+    // The renderer keeps only linear and radial gradients upright (`paint::fill_path`).
+    let rotate = cmd::parse_params(about).unwrap().into_iter().find(|p| p.name == "rotateWithShape").unwrap().about;
+    assert!(rotate.contains("rectangular and path gradients turn with the shape"), "{rotate}");
     for kind in ["linear", "radial", "rectangular", "path"] {
         assert!(about.contains(kind), "{kind}: {about}");
         let g = cmd::shape::gradient_param(&json!({
@@ -6506,3 +6509,161 @@ fn save_to_image_path_is_an_error_not_zip_bytes() {
     }
     let _ = std::fs::remove_dir_all(&dir);
 }
+
+/// `shape.connect` glues to a shape inside a group, as PowerPoint does: the connector's
+/// end is set to the grouped shape and follows it when the group moves. The glue was dropped at
+/// once (the end stayed `None`) because rerouting only looked at the slide's top-level shapes,
+/// and the sites of a grouped shape were computed in the group's child space.
+#[test]
+fn shape_connect_glues_to_a_shape_inside_a_group() {
+    use deckcraft_model::{ShapeId, ShapeKind};
+    let mut s = session();
+    s.execute("slide.new", &json!({"layout": "blank"})).unwrap();
+    let a = s.execute("shape.insert", &json!({"preset": "rect", "rect": [10, 10, 100, 50]})).unwrap()["id"].as_u64().unwrap();
+    let b = s.execute("shape.insert", &json!({"preset": "rect", "rect": [10, 200, 100, 50]})).unwrap()["id"].as_u64().unwrap();
+    let g = s.execute("arrange.group", &json!({"ids": [a, b]})).unwrap()["id"].as_u64().unwrap();
+    let c = s.execute("shape.insert", &json!({"preset": "rect", "rect": [400, 10, 100, 50]})).unwrap()["id"].as_u64().unwrap();
+    let glue = |s: &Session, id: u64| {
+        let st = s.doc().unwrap();
+        match st.shape(ShapeId(id as u32)).unwrap().kind {
+            ShapeKind::Connector { start, end } => (start.map(|(i, _)| i.0 as u64), end.map(|(i, _)| i.0 as u64)),
+            _ => (None, None),
+        }
+    };
+    let near = |p: deckcraft_geom::Point, x: f64, y: f64| (p.x - x).abs() < 1e-6 && (p.y - y).abs() < 1e-6;
+    // A new connector into the group.
+    let r = s.execute("shape.connect", &json!({"from": c, "to": a})).unwrap();
+    let k = r["id"].as_u64().unwrap();
+    assert_eq!(glue(&s, k), (Some(c), Some(a)), "{r}");
+    let (p0, p1) = line_ends(&s, k);
+    assert!(near(p0, 400.0, 35.0), "from C's left site: {p0:?}");
+    assert!(near(p1, 110.0, 35.0), "to A's right site in slide space: {p1:?}");
+    s.execute("shape.move", &json!({"ids": [g], "dy": 100})).unwrap();
+    assert_eq!(glue(&s, k), (Some(c), Some(a)), "the glue survives the move");
+    let (_, p1) = line_ends(&s, k);
+    assert!(near(p1, 110.0, 135.0), "the connector follows the grouped shape: {p1:?}");
+    // Re-gluing an existing line with `id`.
+    let l = s.execute("shape.insert", &json!({"preset": "straightConnector1", "rect": [600, 400, 50, 50]})).unwrap()["id"].as_u64().unwrap();
+    let r = s.execute("shape.connect", &json!({"id": l, "from": c, "to": b})).unwrap();
+    assert_eq!(r["id"], l, "{r}");
+    assert_eq!(glue(&s, l), (Some(c), Some(b)), "{r}");
+    let (_, p1) = line_ends(&s, l);
+    assert!(near(p1, 110.0, 325.0), "to B's right site (C is mostly to its right) in slide space, B moved with the group: {p1:?}");
+    s.execute("shape.move", &json!({"ids": [g], "dx": 50})).unwrap();
+    assert_eq!(glue(&s, l), (Some(c), Some(b)));
+    let (_, p1) = line_ends(&s, l);
+    assert!(near(p1, 160.0, 325.0), "{p1:?}");
+    // shape.sites answers in slide space, as shape.connect uses them: A's right site, A moved
+    // with the group.
+    let v = s.execute("shape.sites", &json!({"id": a})).unwrap();
+    assert!(
+        v.as_array().unwrap().iter().any(|q| near(deckcraft_geom::Point::new(q[0].as_f64().unwrap(), q[1].as_f64().unwrap()), 160.0, 135.0)),
+        "{v}"
+    );
+    // A line inside a group is refused as `id`: its ends would be written in slide space into
+    // the group's space, and rerouting does not follow grouped connectors.
+    let m = s.execute("shape.insert", &json!({"preset": "line", "rect": [600, 300, 50, 0]})).unwrap()["id"].as_u64().unwrap();
+    let n = s.execute("shape.insert", &json!({"preset": "rect", "rect": [600, 450, 50, 50]})).unwrap()["id"].as_u64().unwrap();
+    s.execute("arrange.group", &json!({"ids": [m, n]})).unwrap();
+    let before = s.doc().unwrap().doc.clone();
+    let e = s.execute("shape.connect", &json!({"id": m, "from": c, "to": b})).unwrap_err().to_string();
+    assert!(e.contains("inside a group"), "{e}");
+    assert_eq!(s.doc().unwrap().doc, before, "nothing changed");
+    // A grouped shape that is not a line is refused as not a line, not as a grouped line.
+    let e = s.execute("shape.connect", &json!({"id": n, "from": c, "to": b})).unwrap_err().to_string();
+    assert!(e.contains("not a line"), "{e}");
+    assert_eq!(s.doc().unwrap().doc, before, "nothing changed");
+}
+
+#[test]
+fn flip_is_refused_on_a_smartart_graphic_and_leaves_it_a_graphic() {
+    let mut s = session();
+    s.execute("slide.new", &json!({"layout": "blank"})).unwrap();
+    s.execute("insert.textBox", &json!({"text": "Goals\nRevenue"})).unwrap();
+    let gid = s.execute("smartArt.fromText", &json!({"kind": "blockList"})).unwrap()["id"].as_u64().unwrap();
+    for cmd in ["arrange.flipHorizontal", "arrange.flipVertical", "shape.flip"] {
+        let e = s.execute(cmd, &json!({"ids": [gid]})).unwrap_err().to_string();
+        assert!(e.contains("SmartArt") && e.contains("smartArt.layout"), "{cmd}: {e}");
+    }
+    // Grouped with another shape it cannot be flipped either: ungrouping would hand it the flip.
+    let other = s.execute("insert.textBox", &json!({"text": "x"})).unwrap()["id"].as_u64().unwrap();
+    let group = s.execute("arrange.group", &json!({"ids": [gid, other]})).unwrap()["id"].as_u64().unwrap();
+    let e = s.execute("shape.flip", &json!({"ids": [group]})).unwrap_err().to_string();
+    assert!(e.contains("SmartArt"), "{e}");
+    s.execute("arrange.ungroup", &json!({"ids": [group]})).unwrap();
+    // Still a SmartArt graphic: smartArt commands keep working.
+    s.execute("smartArt.layout", &json!({"id": gid, "kind": "cycle"})).unwrap();
+    // Ordinary shapes still flip.
+    let b = s.execute("insert.textBox", &json!({"text": "x"})).unwrap();
+    let id = b["id"].as_u64().unwrap();
+    assert_eq!(s.execute("arrange.flipHorizontal", &json!({"ids": [id]})).unwrap(), json!(1));
+}
+
+/// Table cell commands refuse a `cells` that is not a list of [row, col] cells in the table,
+/// instead of dropping the entry or reading the list as absent (which acts on the selection).
+#[test]
+fn table_cell_commands_refuse_a_malformed_cells_list() {
+    let mut s = session();
+    let t = table_at(&mut s, &[100.0, 100.0], json!([["a", "b"], ["c", "d"]]));
+    let rev = s.doc().unwrap().revision;
+    for cells in [
+        json!([[-1, 0]]),
+        json!([[0]]),
+        json!([[0, 0], "x"]),
+        json!([[0, 0, "x"]]),
+        json!([[0, 2]]),
+        json!([[0, u64::MAX]]),
+        json!("0,0"),
+        json!({"0": 0}),
+    ] {
+        for (cmd, extra) in [
+            ("table.cellFill", json!({"color": "#FF0000"})),
+            ("table.cellMargins", json!({"left": 4})),
+            ("table.cellAlign", json!({"align": "center"})),
+            ("table.borders", json!({"which": "right"})),
+        ] {
+            let mut p = extra.clone();
+            p["id"] = json!(t);
+            p["cells"] = cells.clone();
+            let e = s.execute(cmd, &p).unwrap_err().to_string();
+            assert!(e.contains(cmd) && e.contains("cell"), "{cmd} {cells}: {e}");
+        }
+    }
+    assert_eq!(s.doc().unwrap().revision, rev, "nothing changed");
+    let many = json!(vec![[0, 0]; 100_001]);
+    assert!(s.execute("table.cellFill", &json!({"id": t, "color": "#FF0000", "cells": many})).unwrap_err().to_string().contains("at most"));
+    s.execute("table.cellFill", &json!({"id": t, "color": "#FF0000", "cells": [[1, 1]]})).unwrap();
+    assert!(table_of(&s, t).cell(1, 1).unwrap().fill.is_some() && table_of(&s, t).cell(0, 0).unwrap().fill.is_none());
+}
+
+/// The outline exports (PowerPoint's outline view) holds titles and body text only: footer,
+/// date and slide-number placeholders are not body lines.
+#[test]
+fn outline_export_skips_footer_date_and_slide_number() {
+    let mut s = session();
+    s.execute("slide.new", &json!({"layout": "titleAndContent", "title": "Agenda", "body": "First point\nSecond point"})).unwrap();
+    s.execute(
+        "design.headerFooter",
+        &json!({"footer": true, "footerText": "Company Confidential", "slideNumber": true, "date": true, "dateText": "1 May 2026"}),
+    )
+    .unwrap();
+    let dir = std::env::temp_dir().join(format!("deckcraft-outline-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    std::fs::create_dir_all(&dir).unwrap();
+    let path = dir.join("deck.md");
+    s.execute("file.export", &json!({"path": path.to_string_lossy(), "format": "outline"})).unwrap();
+    let text = std::fs::read_to_string(&path).unwrap();
+    let _ = std::fs::remove_dir_all(&dir);
+    assert!(text.contains("Agenda") && text.contains("First point") && text.contains("Second point"), "{text:?}");
+    assert!(!text.contains("Company Confidential"), "footer text is not a body line: {text:?}");
+    assert!(!text.contains("‹#›"), "the slide-number field is not a body line: {text:?}");
+    assert!(!text.contains("1 May 2026"), "the date is not a body line: {text:?}");
+    // The RTF outline (Save As ▸ Outline/RTF) too.
+    std::fs::create_dir_all(&dir).unwrap();
+    let path = dir.join("deck.rtf");
+    s.execute("file.export", &json!({"path": path.to_string_lossy(), "format": "rtf"})).unwrap();
+    let rtf = std::fs::read_to_string(&path).unwrap();
+    let _ = std::fs::remove_dir_all(&dir);
+    assert!(rtf.contains("Agenda") && rtf.contains("First point"), "{rtf:?}");
+    assert!(!rtf.contains("Company Confidential") && !rtf.contains("1 May 2026"), "{rtf:?}");
+}

crates/engine/src/tools/drag.rs

@@ -236,7 +236,12 @@ impl Session {
                 }
             }
             // A connector dragged away from shapes that stay put comes unglued at those ends.
-            let moved: Vec<ShapeId> = origs2.iter().map(|o| o.0).collect();
+            let mut moved: Vec<ShapeId> = vec![];
+            for (id, _) in &origs2 {
+                if let Some(sh) = deckcraft_model::find_shape(list, *id) {
+                    deckcraft_model::walk(std::slice::from_ref(sh), &mut |s, _| moved.push(s.id));
+                }
+            }
             for sh in list.iter_mut().filter(|s| moved.contains(&s.id)) {
                 if let ShapeKind::Connector { start, end } = &mut sh.kind {
                     for c in [start, end] {

crates/fonts/src/fallback.rs

@@ -227,6 +227,9 @@ impl FontDb {
     }
 }
 
+/// Most caret records read for one ligature glyph.
+const MAX_LIGATURE_CARETS: usize = 64;
+
 /// Caret positions inside a ligature glyph from GDEF `LigCaretList`, in font units from the
 /// glyph's origin (sorted ascending). Empty when the font has none for `gid`.
 pub fn ligature_carets(face: &FontFace, gid: u32) -> Vec<i32> {
@@ -236,9 +239,12 @@ pub fn ligature_carets(face: &FontFace, gid: u32) -> Vec<i32> {
     let Ok(cov) = list.coverage() else { return Vec::new() };
     let Some(idx) = cov.get(skrifa::GlyphId::new(gid)) else { return Vec::new() };
     let Ok(lig) = list.lig_glyphs().get(idx as usize) else { return Vec::new() };
+    // The limit applies to the records read, not to the carets kept: a font can list thousands of
+    // records it then has to be read through for every ligature laid out.
     let mut out: Vec<i32> = lig
         .caret_values()
         .iter()
+        .take(MAX_LIGATURE_CARETS)
         .filter_map(|cv| cv.ok())
         .filter_map(|cv| match cv {
             skrifa::raw::tables::gdef::CaretValue::Format1(f) => Some(f.coordinate() as i32),
@@ -246,7 +252,6 @@ pub fn ligature_carets(face: &FontFace, gid: u32) -> Vec<i32> {
             // Format 2 is a contour point index; outlines aren't consulted here.
             skrifa::raw::tables::gdef::CaretValue::Format2(_) => None,
         })
-        .take(64)
         .collect();
     out.sort_unstable();
     out

crates/fonts/src/fontdb.rs

@@ -368,7 +368,7 @@ struct CatalogEntry {
 /// Process-wide font database.
 pub struct FontDb {
     faces: RwLock<Vec<Arc<FontFace>>>,
-    outlines: Mutex<HashMap<(u32, u32), Arc<BezPath>>>,
+    outlines: Mutex<OutlineCache>,
     #[cfg(not(target_arch = "wasm32"))]
     catalog: RwLock<Vec<CatalogEntry>>,
     /// The folders the system font scan reads (the platform's font folders for [`FontDb::global`]).
@@ -439,6 +439,38 @@ const SYSTEM_FALLBACKS: &[&str] = &[
 
 static NEXT_ID: AtomicU32 = AtomicU32::new(1);
 const OUTLINE_CACHE_MAX: usize = 50_000;
+/// Most path elements one glyph outline may expand to. Composite and `VARC` glyphs can draw a
+/// shared outline many times over; a glyph past this draws nothing rather than holding megabytes.
+const MAX_OUTLINE_ELEMENTS: usize = 1 << 15;
+/// Most path elements the outline cache holds across all glyphs (about 230 MB at most) before it
+/// starts over: distinct glyph ids can each expand one dense outline.
+const OUTLINE_CACHE_MAX_ELEMENTS: usize = 1 << 22;
+
+/// Glyph outlines by (face, glyph), with the path elements they hold.
+#[derive(Default)]
+struct OutlineCache {
+    paths: HashMap<(u32, u32), Arc<BezPath>>,
+    elements: usize,
+}
+
+impl OutlineCache {
+    fn get(&self, key: &(u32, u32)) -> Option<Arc<BezPath>> {
+        self.paths.get(key).cloned()
+    }
+
+    fn insert(&mut self, key: (u32, u32), path: Arc<BezPath>) {
+        let n = path.elements().len();
+        if let Some(old) = self.paths.remove(&key) {
+            self.elements = self.elements.saturating_sub(old.elements().len());
+        }
+        if self.paths.len() >= OUTLINE_CACHE_MAX || self.elements.saturating_add(n) > OUTLINE_CACHE_MAX_ELEMENTS {
+            self.paths.clear();
+            self.elements = 0;
+        }
+        self.paths.insert(key, path);
+        self.elements = self.elements.saturating_add(n);
+    }
+}
 
 fn name(font: &skrifa::FontRef<'_>, ids: &[StringId]) -> Option<String> {
     ids.iter().find_map(|id| font.localized_strings(*id).english_or_first().map(|s| s.to_string()).filter(|s| !s.is_empty()))
@@ -694,6 +726,10 @@ const MAX_COLLECTION_FACES: u32 = 256;
 const MAX_COLLECTION_ENTRIES_SCANNED: u32 = 16_384;
 /// Maximum named instances read from a single face.
 const MAX_NAMED_INSTANCES_PER_FACE: usize = 1024;
+/// Maximum faces (named instances counted separately) enumerated from one font file, across all
+/// of a collection's faces: the per-collection and per-face limits multiply, and each face found
+/// is then built with its own shaper.
+const MAX_ENUMERATED_FACES: usize = 4096;
 
 fn distinct_face_indices(entries: impl IntoIterator<Item = (u32, u32)>) -> Vec<u32> {
     let mut offsets = std::collections::HashSet::new();
@@ -730,21 +766,30 @@ fn enumerate_faces(data: &[u8]) -> Vec<Found> {
         Err(_) => Vec::new(),
     };
     let mut out = Vec::new();
+    // Named instances read and plain faces kept, across the whole file.
+    let mut budget = MAX_ENUMERATED_FACES;
     for i in indices {
+        if budget == 0 {
+            break;
+        }
         let Ok(f) = skrifa::FontRef::from_index(data, i) else { continue };
         let Some((family, style)) = face_names(&f) else { continue };
         let axes = f.axes();
         let mut named = Vec::new();
+        let mut seen = std::collections::HashSet::new();
         let instances = f.named_instances();
         for ni in instances.iter().take(capped_named_instance_count(instances.len())) {
+            let Some(left) = budget.checked_sub(1) else { break };
+            budget = left;
             let Some(style) = name(&f, &[ni.subfamily_name_id()]) else { continue };
-            if named.iter().any(|(_, s, _): &(u32, String, _)| s.eq_ignore_ascii_case(&style)) {
+            if !seen.insert(style.to_ascii_lowercase()) {
                 continue;
             }
             let coords: Vec<([u8; 4], f32)> = axes.iter().zip(ni.user_coords()).map(|(a, v)| (a.tag().to_be_bytes(), v)).collect();
             named.push((i, style, coords));
         }
         if named.is_empty() {
+            budget = budget.saturating_sub(1);
             out.push((i, family, style, Vec::new()));
         } else {
             out.extend(named.into_iter().map(|(i, s, c)| (i, family.clone(), s, c)));
@@ -905,7 +950,7 @@ impl FontDb {
         }
         Self {
             faces: RwLock::new(faces),
-            outlines: Mutex::new(HashMap::new()),
+            outlines: Mutex::new(OutlineCache::default()),
             #[cfg(not(target_arch = "wasm32"))]
             catalog: RwLock::new(Vec::new()),
             font_dirs,
@@ -1215,9 +1260,8 @@ impl FontDb {
     fn instance(&self, family: &str, style: &str) -> Option<Arc<FontFace>> {
         let open = style.find('{')?;
         let base = self.find(family, style[..open].trim())?;
-        if base.skrifa().is_none_or(|f| f.axes().is_empty()) {
-            return Some(base);
-        }
+        let Some(font) = base.skrifa().filter(|f| !f.axes().is_empty()) else { return Some(base) };
+        let axis_tags: Vec<[u8; 4]> = font.axes().iter().map(|a| a.tag().to_be_bytes()).collect();
         let mut coords = base.coords.clone();
         for kv in style[open + 1..].trim_end_matches('}').split(',') {
             let (k, v) = kv.split_once(':')?;
@@ -1227,6 +1271,11 @@ impl FontDb {
                 return None;
             }
             let tag = [k[0], k[1], k[2], k[3]];
+            // A tag the font has no axis for changes nothing; keeping it would grow the list with
+            // every distinct tag in the style text.
+            if !axis_tags.contains(&tag) {
+                continue;
+            }
             match coords.iter_mut().find(|(t, _)| *t == tag) {
                 Some(c) => c.1 = v,
                 None => coords.push((tag, v)),
@@ -1513,41 +1562,72 @@ impl FontDb {
     pub fn outline(&self, face: &FontFace, gid: u32) -> Arc<BezPath> {
         let key = (face.id, gid);
         if let Some(p) = self.outlines.lock().unwrap_or_else(std::sync::PoisonError::into_inner).get(&key) {
-            return p.clone();
+            return p;
         }
-        let mut pen = FlipPen(BezPath::new());
+        let mut pen = FlipPen::new(MAX_OUTLINE_ELEMENTS);
         if let Some(f) = face.skrifa()
             && let Some(g) = f.outline_glyphs().get(GlyphId::new(gid))
         {
             let _ = g.draw(DrawSettings::unhinted(Size::unscaled(), face.location()), &mut pen);
         }
-        let p = Arc::new(pen.0);
-        let mut cache = self.outlines.lock().unwrap_or_else(std::sync::PoisonError::into_inner);
-        if cache.len() >= OUTLINE_CACHE_MAX {
-            cache.clear();
-        }
-        cache.insert(key, p.clone());
+        let p = Arc::new(pen.finish());
+        self.outlines.lock().unwrap_or_else(std::sync::PoisonError::into_inner).insert(key, p.clone());
         p
     }
 }
 
-struct FlipPen(BezPath);
+/// Collects a glyph outline, y flipped, up to `limit` path elements. Past the limit it ignores
+/// what follows and [`FlipPen::finish`] gives an empty path: a cut-off outline would fill wrongly.
+struct FlipPen {
+    path: BezPath,
+    limit: usize,
+    over: bool,
+}
+
+impl FlipPen {
+    fn new(limit: usize) -> Self {
+        FlipPen { path: BezPath::new(), limit, over: false }
+    }
+
+    /// Room for one more element?
+    fn room(&mut self) -> bool {
+        if !self.over && self.path.elements().len() >= self.limit {
+            self.over = true;
+            self.path = BezPath::new();
+        }
+        !self.over
+    }
+
+    fn finish(self) -> BezPath {
+        if self.over { BezPath::new() } else { self.path }
+    }
+}
 
 impl OutlinePen for FlipPen {
     fn move_to(&mut self, x: f32, y: f32) {
-        self.0.move_to((x as f64, -y as f64));
+        if self.room() {
+            self.path.move_to((x as f64, -y as f64));
+        }
     }
     fn line_to(&mut self, x: f32, y: f32) {
-        self.0.line_to((x as f64, -y as f64));
+        if self.room() {
+            self.path.line_to((x as f64, -y as f64));
+        }
     }
     fn quad_to(&mut self, cx0: f32, cy0: f32, x: f32, y: f32) {
-        self.0.quad_to((cx0 as f64, -cy0 as f64), (x as f64, -y as f64));
+        if self.room() {
+            self.path.quad_to((cx0 as f64, -cy0 as f64), (x as f64, -y as f64));
+        }
     }
     fn curve_to(&mut self, cx0: f32, cy0: f32, cx1: f32, cy1: f32, x: f32, y: f32) {
-        self.0.curve_to((cx0 as f64, -cy0 as f64), (cx1 as f64, -cy1 as f64), (x as f64, -y as f64));
+        if self.room() {
+            self.path.curve_to((cx0 as f64, -cy0 as f64), (cx1 as f64, -cy1 as f64), (x as f64, -y as f64));
+        }
     }
     fn close(&mut self) {
-        self.0.close_path();
+        if self.room() {
+            self.path.close_path();
+        }
     }
 }
 
@@ -1575,6 +1655,55 @@ mod font_dir_tests {
         assert_eq!(capped_named_instance_count(MAX_NAMED_INSTANCES_PER_FACE + 1), MAX_NAMED_INSTANCES_PER_FACE);
     }
 
+    #[test]
+    fn faces_of_one_file_are_bounded_across_the_collection() {
+        // The per-collection and per-face limits together would allow far more.
+        assert!((MAX_COLLECTION_FACES as usize) * MAX_NAMED_INSTANCES_PER_FACE > 16 * MAX_ENUMERATED_FACES);
+        for data in bundled() {
+            assert!(enumerate_faces(data).len() <= MAX_ENUMERATED_FACES);
+        }
+    }
+
+    #[test]
+    fn an_outline_past_the_element_limit_draws_nothing() {
+        let mut pen = FlipPen::new(8);
+        pen.move_to(0.0, 0.0);
+        pen.line_to(1.0, 1.0);
+        pen.close();
+        assert_eq!(pen.finish().elements().len(), 3);
+        // A shared outline drawn over and over (composite and VARC glyphs).
+        let mut pen = FlipPen::new(8);
+        for i in 0..1_000_000 {
+            pen.move_to(0.0, 0.0);
+            pen.line_to(i as f32, 1.0);
+            pen.close();
+        }
+        assert_eq!(pen.path.elements().len(), 0);
+        assert!(pen.finish().elements().is_empty());
+    }
+
+    #[test]
+    fn outline_cache_is_bounded_by_elements() {
+        let mut path = BezPath::new();
+        path.move_to((0.0, 0.0));
+        for i in 1..MAX_OUTLINE_ELEMENTS {
+            path.line_to((i as f64, 0.0));
+        }
+        let path = Arc::new(path);
+        let mut cache = OutlineCache::default();
+        let glyphs = 4 * OUTLINE_CACHE_MAX_ELEMENTS / MAX_OUTLINE_ELEMENTS;
+        for gid in 0..glyphs as u32 {
+            cache.insert((1, gid), path.clone());
+            assert!(cache.elements <= OUTLINE_CACHE_MAX_ELEMENTS);
+            assert_eq!(cache.elements, cache.paths.values().map(|p| p.elements().len()).sum::<usize>());
+        }
+        assert!(cache.get(&(1, glyphs as u32 - 1)).is_some());
+        // Replacing an entry does not count it twice.
+        let before = cache.elements;
+        cache.insert((1, glyphs as u32 - 1), path.clone());
+        assert_eq!(cache.elements, before);
+    }
+
     #[test]
     fn xdg_data_dirs_contribute_their_fonts_folders() {
         let home = Path::new("/home/ann");

crates/format/src/lib.rs

@@ -247,6 +247,11 @@ pub fn repair(p: &mut Presentation) {
     if !(p.notes_size.width.is_finite() && p.notes_size.width > 0.0 && p.notes_size.height.is_finite() && p.notes_size.height > 0.0) {
         p.notes_size = Presentation::default().notes_size;
     }
+    // A notes page is bounded like a slide: canvas and handout drawing scale with it.
+    p.notes_size = deckcraft_model::Size::new(
+        p.notes_size.width.clamp(*SLIDE_SIDE.start(), *SLIDE_SIDE.end()),
+        p.notes_size.height.clamp(*SLIDE_SIDE.start(), *SLIDE_SIDE.end()),
+    );
     sane_numbers(p);
 }
 
@@ -689,7 +694,9 @@ pub fn slides_to_outline(p: &Presentation) -> String {
         out.push_str(&s.title().replace('\n', " "));
         out.push('\n');
         for sh in &s.shapes {
-            if sh.ph_type().is_some_and(|k| k.is_title()) {
+            // The title is the slide's line; footer, date and slide-number placeholders are not
+            // body text (PowerPoint's outline view shows title and body placeholders only).
+            if sh.ph_type().is_some_and(|k| k.is_title() || k.is_footer_kind()) {
                 continue;
             }
             if let Some(t) = &sh.text {

crates/format/src/rtf.rs

@@ -71,7 +71,8 @@ pub fn slides_to_rtf(p: &Presentation) -> String {
         }
         out.push_str("\\b0\\par\n");
         for sh in &s.shapes {
-            if sh.ph_type().is_some_and(|k| k.is_title()) {
+            // As in the text outline: footer, date and slide-number placeholders are not body text.
+            if sh.ph_type().is_some_and(|k| k.is_title() || k.is_footer_kind()) {
                 continue;
             }
             let Some(t) = &sh.text else { continue };
@@ -299,7 +300,8 @@ impl Outline<'_> {
 
     /// A one-character control symbol (`\\`, `\{`, `\~`, ...).
     fn symbol(&mut self, n: u8) {
-        self.i += 1;
+        let c = self.rtf.get(self.i..).and_then(|r| r.chars().next());
+        self.i = advance(self.rtf, self.i, 1);
         if self.st.skip {
             return;
         }
@@ -308,6 +310,7 @@ impl Outline<'_> {
             b'~' => self.line.push('\u{a0}'),
             b'_' => self.line.push('\u{2011}'),
             b'\n' | b'\r' => self.flush(),
+            _ if !n.is_ascii() => self.line.extend(c),
             _ => {}
         }
     }
@@ -419,6 +422,11 @@ mod tests {
         assert_eq!(rtf_to_outline(r"{\rtf1 x\u-70000?y\par}"), "x\u{ee90}y\n");
     }
 
+    #[test]
+    fn multibyte_control_symbol_keeps_character_and_following_text() {
+        assert_eq!(rtf_to_outline("{\\rtf1 A\\éB\\par}"), "AéB\n");
+    }
+
     /// `\\_` is RTF's non-breaking hyphen: a visible character, not markup.
     #[test]
     fn non_breaking_hyphen_is_kept() {

crates/format/src/tests.rs

@@ -451,6 +451,13 @@ fn degenerate_slide_sizes_are_repaired() {
     }
 }
 
+#[test]
+fn repair_bounds_the_notes_page_size() {
+    let mut p = Presentation { notes_size: deckcraft_model::Size::new(1e12, 0.01), ..Default::default() };
+    repair(&mut p);
+    assert_eq!((p.notes_size.width, p.notes_size.height), (4032.0, 72.0));
+}
+
 /// A file whose slide size is null, a string or missing a side (written by hand or by
 /// another tool; NaN is also saved as null) opens with the default size rather than failing
 /// as damaged.

crates/geom/src/morph.rs

@@ -126,6 +126,21 @@ fn split_curve(c: &[Point], n: usize, out: &mut Vec<Point>) {
     out.extend([p1, p2, p3]);
 }
 
+/// A piece length ordered totally, so it can sit in a heap.
+#[derive(PartialEq)]
+struct Share(f64);
+impl Eq for Share {}
+impl PartialOrd for Share {
+    fn partial_cmp(&self, o: &Self) -> Option<std::cmp::Ordering> {
+        Some(self.cmp(o))
+    }
+}
+impl Ord for Share {
+    fn cmp(&self, o: &Self) -> std::cmp::Ordering {
+        self.0.total_cmp(&o.0)
+    }
+}
+
 /// Brings a contour to `n` curves. Unlike manim (which splits every curve equally often), the extra
 /// splits go to the longest pieces, so a long side gets more points than a short one.
 fn refine(c: &Contour, n: usize) -> Contour {
@@ -136,11 +151,15 @@ fn refine(c: &Contour, n: usize) -> Contour {
     let curves: Vec<&[Point]> = (0..have).filter_map(|k| c.pts.get(3 * k..3 * k + 4)).collect();
     let len: Vec<f64> = curves.iter().map(|q| curve_length(q) + 1e-9).collect();
     let mut parts = vec![1usize; curves.len()];
+    // The curve with the longest piece gets the next split (the lowest index on a tie); a heap keeps
+    // this O(n log n) instead of rescanning every curve for each split.
+    let mut heap: std::collections::BinaryHeap<(Share, std::cmp::Reverse<usize>)> =
+        len.iter().enumerate().map(|(k, l)| (Share(*l), std::cmp::Reverse(k))).collect();
     for _ in 0..n - have {
-        let share = |k: usize| len.get(k).copied().unwrap_or(0.0) / parts.get(k).copied().unwrap_or(1) as f64;
-        let best = (1..curves.len()).fold(0, |b, k| if share(k) > share(b) { k } else { b });
+        let Some((_, std::cmp::Reverse(best))) = heap.pop() else { break };
         if let Some(p) = parts.get_mut(best) {
             *p += 1;
+            heap.push((Share(len.get(best).copied().unwrap_or(0.0) / *p as f64), std::cmp::Reverse(best)));
         }
     }
     let mut out = Vec::with_capacity(1 + 3 * n);
@@ -420,6 +439,16 @@ mod tests {
         assert_eq!(contours(&to_path(&cs)), cs);
     }
 
+    #[test]
+    fn refine_many_curves_finishes_at_the_asked_count() {
+        let mut c = Contour { closed: false, pts: vec![Point::ZERO] };
+        for i in 1..=20_000 {
+            line_to(&mut c.pts, Point::new(f64::from(i), f64::from(i % 7)));
+        }
+        let r = refine(&c, 40_000);
+        assert_eq!(r.curves(), 40_000);
+    }
+
     #[test]
     fn refine_splits_the_longest_curves_and_keeps_the_shape() {
         let c = Contour { closed: false, pts: vec![Point::ZERO, Point::new(1.0, 0.0), Point::new(2.0, 0.0), Point::new(3.0, 0.0)] };

crates/geom/src/warp.rs

@@ -928,11 +928,25 @@ impl Warp {
             k_fill = 1.0;
         }
         zoom = zoom.max(k_fill);
+        // Per band, measured once: its widest line and its first and last lines' baselines.
+        let mut stats: Vec<Option<(f64, f64, f64)>> = vec![None; nb];
+        for (l, &b) in lines.iter().zip(&band_of) {
+            let w = l.extent.1 - l.extent.0;
+            if let Some(slot) = stats.get_mut(b) {
+                match slot {
+                    Some((widest, _, last)) => {
+                        *widest = widest.max(w);
+                        *last = l.ref_y;
+                    }
+                    None => *slot = Some((0.0f64.max(w), l.ref_y, l.ref_y)),
+                }
+            }
+        }
         let mut maps = Vec::with_capacity(n);
         let mut offsets = Vec::new();
         for (i, l) in lines.iter().enumerate() {
             let b = band_of.get(i).copied().unwrap_or(0);
-            let in_band = |j: &usize| band_of.get(*j) == Some(&b);
+            let band = stats.get(b).copied().flatten();
             match self.bands.get(b) {
                 Some(Band::Fill { .. }) | None => {
                     let (y0, y1) = band_y.get(b).copied().flatten().unwrap_or((0.0, 1.0));
@@ -941,16 +955,12 @@ impl Warp {
                 }
                 Some(Band::Follow { path, anchor }) => {
                     let len = path.length();
-                    let widest = (0..n).filter(in_band).filter_map(|j| lines.get(j)).map(|l| l.extent.1 - l.extent.0).fold(0.0, f64::max);
+                    let widest = band.map_or(0.0, |s| s.0);
                     let k = if widest > len && widest > 1e-9 { len / widest } else { 1.0 };
-                    let members: Vec<&WarpLine> = (0..n).filter(in_band).filter_map(|j| lines.get(j)).collect();
                     let ref_y = match anchor {
-                        LineAnchor::Last => members.last().map(|l| l.ref_y),
-                        LineAnchor::First => members.first().map(|l| l.ref_y),
-                        LineAnchor::Middle => match (members.first(), members.last()) {
-                            (Some(a), Some(z)) => Some((a.ref_y + z.ref_y) / 2.0),
-                            _ => None,
-                        },
+                        LineAnchor::Last => band.map(|s| s.2),
+                        LineAnchor::First => band.map(|s| s.1),
+                        LineAnchor::Middle => band.map(|s| (s.1 + s.2) / 2.0),
                     }
                     .unwrap_or(l.ref_y);
                     // Lines off the guide run on a parallel curve at their natural length.

crates/geom/src/warp/tests.rs

@@ -319,3 +319,20 @@ fn arch_and_inflate_handles_follow_the_pointer() {
     assert!(more > adjust_defaults("textInflate")[0], "{more}");
     assert!((more - 20_000.0).abs() < 1.0, "{more}");
 }
+
+#[test]
+fn many_lines_on_a_follow_band_are_mapped_from_one_measurement() {
+    // 50,000 lines on an arch: each line's scale and anchor come from the band measured once.
+    let w = warp("textArchUp", &[], rect()).unwrap();
+    let inner = Rect::new(7.2, 3.6, W - 7.2, H - 3.6);
+    let lines: Vec<WarpLine> = (0..50_000)
+        .map(|i| {
+            let y = i as f64 * 0.01;
+            WarpLine { ink: Some(Rect::new(190.0, y, 230.0, y + 1.0)), extent: (190.0, 230.0), ref_y: y + 1.0 }
+        })
+        .collect();
+    let m = w.mapper(&lines, inner);
+    // The last line sits on the arc, as with two lines.
+    let last = lines.len() - 1;
+    assert!(m.map(last, Point::new(210.0, lines[last].ref_y)).y.abs() < 0.05);
+}

crates/hevc/src/slice.rs

@@ -326,7 +326,9 @@ impl SliceHeader {
 
     /// entry_point_offset list (tiles / wavefront substreams).
     fn parse_entry_points(&mut self, r: &mut BitReader, pps: &Pps, sps: &Sps) -> Result<()> {
-        self.entry_points.clear();
+        // A fresh list, not `clear()`: a dependent segment starts as a copy of its independent
+        // segment's header, and clearing would keep that copy's allocation for every segment.
+        self.entry_points = Vec::new();
         if pps.tiles_enabled || pps.entropy_coding_sync {
             let n = r.read_ue()?;
             ensure!(n <= sps.pic_width_in_ctbs() * sps.pic_height_in_ctbs(), "num_entry_point_offsets out of range");

crates/model/src/chart.rs

@@ -758,17 +758,20 @@ impl Chart {
     }
 
     fn stacked_value_range(&self, n: usize) -> (f64, f64) {
-        let mut lo: f64 = 0.0;
-        let mut hi: f64 = 0.0;
-        for i in 0..n {
-            let (mut p, mut m) = (0.0, 0.0);
-            for s in &self.series {
-                let v = s.values.get(i).copied().flatten().unwrap_or(0.0);
-                if v >= 0.0 { p += v } else { m += v }
+        // Sums per category, from the values the series hold (an absent one adds nothing).
+        let (mut pos, mut neg) = (vec![0.0f64; n], vec![0.0f64; n]);
+        for s in &self.series {
+            for (i, v) in s.values.iter().enumerate().take(n) {
+                let v = v.unwrap_or(0.0);
+                if v >= 0.0 {
+                    pos[i] += v;
+                } else {
+                    neg[i] += v;
+                }
             }
-            hi = hi.max(p);
-            lo = lo.min(m);
         }
+        let hi = pos.iter().fold(0.0f64, |a, &p| a.max(p));
+        let lo = neg.iter().fold(0.0f64, |a, &m| a.min(m));
         (lo, hi)
     }
 
@@ -1348,40 +1351,50 @@ impl Chart {
     /// The box chart's groups (distinct category labels in order of appearance; one unnamed
     /// group without categories) and, per series, each group's summary (None when it has no
     /// points).
+    ///
+    /// Each value is put in its group's bucket once (groups are found by name in a map), and the
+    /// series x groups result is held to [`MAX_BOX_CELLS`]: groups past it are left out.
     pub fn box_groups(&self) -> (Vec<String>, Vec<Vec<Option<BoxStats>>>) {
+        let max_groups = (MAX_BOX_CELLS / self.series.len().max(1)).max(1);
         let mut groups: Vec<String> = Vec::new();
+        let mut index: std::collections::HashMap<&str, usize> = std::collections::HashMap::new();
         for c in &self.categories {
-            if !groups.contains(c) {
+            if !index.contains_key(c.as_str()) && groups.len() < max_groups {
+                index.insert(c, groups.len());
                 groups.push(c.clone());
             }
         }
         if groups.is_empty() {
             groups.push(String::new());
+            index.insert("", 0);
         }
+        // A value past the categories belongs to the unnamed group, when there is one.
+        let past_end = index.get("").copied();
         let stats = self
             .series
             .iter()
             .map(|s| {
-                groups
-                    .iter()
-                    .map(|g| {
-                        let pts: Vec<f64> = s
-                            .values
-                            .iter()
-                            .enumerate()
-                            .filter(|(i, _)| self.categories.get(*i).map_or(g.is_empty() || self.categories.is_empty(), |c| c == g))
-                            .filter_map(|(_, v)| *v)
-                            .filter(|v| v.is_finite())
-                            .collect();
-                        box_stats_by(pts, self.inclusive_quartiles)
-                    })
-                    .collect()
+                let mut buckets: Vec<Vec<f64>> = vec![Vec::new(); groups.len()];
+                for (i, v) in s.values.iter().enumerate() {
+                    let Some(v) = v.filter(|v| v.is_finite()) else { continue };
+                    let g = match self.categories.get(i) {
+                        Some(c) => index.get(c.as_str()).copied(),
+                        None => past_end,
+                    };
+                    if let Some(b) = g.and_then(|g| buckets.get_mut(g)) {
+                        b.push(v);
+                    }
+                }
+                buckets.into_iter().map(|pts| box_stats_by(pts, self.inclusive_quartiles)).collect()
             })
             .collect();
         (groups, stats)
     }
 }
 
+/// Most series x group summaries [`Chart::box_groups`] makes.
+pub const MAX_BOX_CELLS: usize = 1_000_000;
+
 /// Widens the (min, max) extent `ext` to include `v`.
 fn widen(ext: &mut (f64, f64), v: f64) {
     ext.0 = ext.0.min(v);
@@ -1454,33 +1467,41 @@ impl Chart {
         let n = self.categories.len().max(s.values.len());
         let levels: Vec<&Vec<String>> = self.category_levels.iter().take(MAX_LEVELS).collect();
         // Each leaf's path from the top level down, blanks filled from the row above.
-        let mut last: Vec<String> = vec![String::new(); levels.len()];
-        let paths: Vec<Vec<String>> = (0..n)
+        // Labels are shared, not copied: an outer label given once stands for every leaf under it.
+        use std::rc::Rc;
+        let empty: Rc<str> = Rc::from("");
+        let mut last: Vec<Rc<str>> = vec![empty.clone(); levels.len()];
+        let paths: Vec<Vec<Rc<str>>> = (0..n)
             .map(|i| {
                 let mut path = Vec::with_capacity(levels.len() + 1);
                 for (d, lv) in levels.iter().enumerate().rev() {
                     let l = lv.get(i).map(|x| x.trim()).unwrap_or("");
                     if !l.is_empty() {
-                        last[d] = l.to_string();
+                        last[d] = Rc::from(l);
                         // A new outer label starts fresh inner groups.
                         for inner in last.iter_mut().take(d) {
-                            inner.clear();
+                            *inner = empty.clone();
                         }
                     }
                     path.push(last[d].clone());
                 }
-                path.push(self.categories.get(i).cloned().unwrap_or_default());
+                path.push(self.categories.get(i).map_or_else(|| empty.clone(), |c| Rc::from(c.as_str())));
                 path
             })
             .collect();
         let value = |i: usize| s.values.get(i).copied().flatten().filter(|v| v.is_finite()).unwrap_or(0.0).max(0.0);
-        fn build(rows: &[(usize, &[String])], value: &dyn Fn(usize) -> f64) -> Vec<TreeNode> {
+        fn build(rows: &[(usize, &[std::rc::Rc<str>])], value: &dyn Fn(usize) -> f64) -> Vec<TreeNode> {
             let mut out: Vec<TreeNode> = Vec::new();
             let mut i = 0;
             while i < rows.len() {
                 let (idx, path) = rows[i];
                 if path.len() <= 1 {
-                    out.push(TreeNode { name: path.first().cloned().unwrap_or_default(), value: value(idx), leaf: Some(idx), children: vec![] });
+                    out.push(TreeNode {
+                        name: path.first().map(|p| p.to_string()).unwrap_or_default(),
+                        value: value(idx),
+                        leaf: Some(idx),
+                        children: vec![],
+                    });
                     i += 1;
                     continue;
                 }
@@ -1489,14 +1510,14 @@ impl Chart {
                 while j < rows.len() && rows[j].1.len() > 1 && &rows[j].1[0] == head {
                     j += 1;
                 }
-                let sub: Vec<(usize, &[String])> = rows[i..j].iter().map(|(k, p)| (*k, &p[1..])).collect();
+                let sub: Vec<(usize, &[std::rc::Rc<str>])> = rows[i..j].iter().map(|(k, p)| (*k, &p[1..])).collect();
                 let children = build(&sub, value);
-                out.push(TreeNode { name: head.clone(), value: children.iter().map(|c| c.value).sum(), leaf: None, children });
+                out.push(TreeNode { name: head.to_string(), value: children.iter().map(|c| c.value).sum(), leaf: None, children });
                 i = j;
             }
             out
         }
-        let rows: Vec<(usize, &[String])> = paths.iter().enumerate().map(|(i, p)| (i, p.as_slice())).collect();
+        let rows: Vec<(usize, &[Rc<str>])> = paths.iter().enumerate().map(|(i, p)| (i, p.as_slice())).collect();
         build(&rows, &value)
     }
 }
@@ -1607,6 +1628,40 @@ mod chartex_tests {
         assert!(c.category_tree().iter().all(|n| n.leaf.is_some()));
     }
 
+    #[test]
+    fn large_box_hierarchy_and_stacked_charts_take_linear_work() {
+        // 50,000 distinct categories in one series: grouped through a map, one pass.
+        let n = 50_000;
+        let mut c = Chart::sample(ChartType::BoxWhisker);
+        c.series.truncate(1);
+        c.categories = (0..n).map(|i| format!("g{i}")).collect();
+        c.series[0].values = (0..n).map(|i| Some(i as f64)).collect();
+        let (groups, stats) = c.box_groups();
+        assert_eq!((groups.len(), stats[0].len()), (n, n));
+        assert!(stats[0].iter().all(Option::is_some));
+        // 2,000 series cap the groups so the result stays within MAX_BOX_CELLS.
+        c.series = vec![c.series[0].clone(); 2000];
+        let (groups, stats) = c.box_groups();
+        assert_eq!(groups.len(), MAX_BOX_CELLS / 2000);
+        assert!(stats.iter().all(|s| s.len() == groups.len()));
+        // One long outer label over 50,000 leaves is shared, not copied per leaf.
+        let mut t = Chart::sample(ChartType::Treemap);
+        t.series.truncate(1);
+        t.categories = (0..n).map(|i| format!("c{i}")).collect();
+        t.series[0].values = (0..n).map(|_| Some(1.0)).collect();
+        let mut outer = vec![String::new(); n];
+        outer[0] = "o".repeat(1 << 16);
+        t.category_levels = vec![outer];
+        let tree = t.category_tree();
+        assert_eq!(tree.len(), 1);
+        assert_eq!(tree[0].children.len(), n);
+        // Stacked sums over many sparse series.
+        let mut st = Chart::sample(ChartType::StackedBar);
+        st.categories = (0..n).map(|i| i.to_string()).collect();
+        st.series = (0..2000).map(|k| Series { values: vec![Some(1.0); if k == 0 { n } else { 1 }], ..Default::default() }).collect();
+        assert!(st.value_range().1 >= 2000.0, "{:?}", st.value_range());
+    }
+
     #[test]
     fn box_groups_follow_category_labels() {
         let c = Chart::sample(ChartType::BoxWhisker);

crates/model/src/edit.rs

@@ -78,45 +78,57 @@ pub fn insert(body: &mut TextBody, pos: Pos, text: &str, props: Option<RunProps>
     if body.paragraphs.is_empty() {
         body.paragraphs.push(Paragraph::default());
     }
-    let (mut pi, mut ch) = clamp(body, pos);
-    let props = props.unwrap_or_else(|| props_at(body, (pi, ch)));
+    let (pi0, mut ch) = clamp(body, pos);
+    let props = props.unwrap_or_else(|| props_at(body, (pi0, ch)));
     let text = text.replace("\r\n", "\n").replace('\r', "\n");
+    // Work on the paragraph being edited apart from the body, so each new paragraph is pushed to a
+    // list and the body's vector is spliced once instead of shifted for every `\n`.
+    let Some(slot) = body.paragraphs.get_mut(pi0) else { return (pi0, ch) };
+    let mut cur = std::mem::take(slot);
+    let mut done: Vec<Paragraph> = Vec::new();
     let mut first = true;
     for part in text.split('\n') {
         if !first {
-            // Split paragraph pi at ch.
-            let Some(p) = body.paragraphs.get_mut(pi) else { break };
-            let idx = split_at(p, ch);
-            let tail: Vec<Run> = p.runs.drain(idx..).collect();
-            let newp =
-                Paragraph { level: p.level, props: p.props.clone(), runs: tail, def_props: p.def_props.clone(), end_props: p.end_props.clone() };
-            p.end_props = props.clone();
-            body.paragraphs.insert(pi + 1, newp);
-            pi += 1;
+            // Split the current paragraph at ch.
+            let idx = split_at(&mut cur, ch);
+            let tail: Vec<Run> = cur.runs.drain(idx..).collect();
+            let newp = Paragraph {
+                level: cur.level,
+                props: cur.props.clone(),
+                runs: tail,
+                def_props: cur.def_props.clone(),
+                end_props: cur.end_props.clone(),
+            };
+            cur.end_props = props.clone();
+            done.push(std::mem::replace(&mut cur, newp));
             ch = 0;
         }
         first = false;
+        // The run index just after the last insertion: the next one lands there with no rescan.
+        let mut next: Option<usize> = None;
         for (k, seg) in part.split('\u{b}').enumerate() {
-            let Some(p) = body.paragraphs.get_mut(pi) else { break };
             if k > 0 {
-                let idx = split_at(p, ch);
-                p.runs.insert(idx, Run { text: String::new(), props: props.clone(), kind: RunKind::Break });
+                let idx = next.unwrap_or_else(|| split_at(&mut cur, ch));
+                cur.runs.insert(idx, Run { text: String::new(), props: props.clone(), kind: RunKind::Break });
                 ch += 1;
+                next = Some(idx + 1);
             }
             if seg.is_empty() {
                 continue;
             }
-            let idx = split_at(p, ch);
-            p.runs.insert(idx, Run::with(seg, props.clone()));
+            let idx = next.unwrap_or_else(|| split_at(&mut cur, ch));
+            cur.runs.insert(idx, Run::with(seg, props.clone()));
             ch += seg.chars().count();
+            next = Some(idx + 1);
         }
-        if let Some(p) = body.paragraphs.get_mut(pi) {
-            p.normalize();
-            if p.runs.is_empty() {
-                p.end_props = props.clone();
-            }
+        cur.normalize();
+        if cur.runs.is_empty() {
+            cur.end_props = props.clone();
         }
     }
+    let pi = pi0 + done.len();
+    done.push(cur);
+    body.paragraphs.splice(pi0..=pi0, done);
     (pi, ch)
 }
 
@@ -252,8 +264,16 @@ pub fn slice(body: &TextBody, a: Pos, b: Pos) -> TextBody {
 /// Insert a formatted body at `pos` (paste): first paragraph merges into the current one.
 pub fn insert_body(body: &mut TextBody, pos: Pos, src: &TextBody) -> Pos {
     let mut caret = clamp(body, pos);
+    // Plain text runs go straight in at the run index after the previous one and the paragraph is
+    // normalized once, not rescanned and merged for every source run.
+    let mut next: Option<usize> = None;
+    let mut dirty = false;
     for (k, sp) in src.paragraphs.iter().enumerate() {
         if k > 0 {
+            if let (true, Some(p)) = (dirty, body.paragraphs.get_mut(caret.0)) {
+                p.normalize();
+            }
+            (next, dirty) = (None, false);
             caret = insert(body, caret, "\n", None);
             if let Some(p) = body.paragraphs.get_mut(caret.0) {
                 p.level = sp.level;
@@ -261,6 +281,22 @@ pub fn insert_body(body: &mut TextBody, pos: Pos, src: &TextBody) -> Pos {
             }
         }
         for r in &sp.runs {
+            if r.kind == RunKind::Text
+                && !r.text.is_empty()
+                && !r.text.contains(['\n', '\r', '\u{b}'])
+                && let Some(p) = body.paragraphs.get_mut(caret.0)
+            {
+                let idx = next.unwrap_or_else(|| split_at(p, caret.1));
+                p.runs.insert(idx, Run::with(&r.text, r.props.clone()));
+                caret.1 += r.text.chars().count();
+                (next, dirty) = (Some(idx + 1), true);
+                continue;
+            }
+            // Anything else takes the general path, after the pending runs are merged.
+            if let (true, Some(p)) = (dirty, body.paragraphs.get_mut(caret.0)) {
+                p.normalize();
+            }
+            (next, dirty) = (None, false);
             match r.kind {
                 RunKind::Text => caret = insert(body, caret, &r.text, Some(r.props.clone())),
                 RunKind::Break => caret = insert(body, caret, "\u{b}", Some(r.props.clone())),
@@ -274,6 +310,9 @@ pub fn insert_body(body: &mut TextBody, pos: Pos, src: &TextBody) -> Pos {
             }
         }
     }
+    if let (true, Some(p)) = (dirty, body.paragraphs.get_mut(caret.0)) {
+        p.normalize();
+    }
     caret
 }
 
@@ -568,6 +607,74 @@ mod tests {
         assert_eq!(caret, (0, 5));
     }
 
+    /// The paste as it ran before the fast path: one `insert` (and normalize) per source run.
+    fn insert_body_by_runs(body: &mut TextBody, pos: Pos, src: &TextBody) -> Pos {
+        let mut caret = clamp(body, pos);
+        for (k, sp) in src.paragraphs.iter().enumerate() {
+            if k > 0 {
+                caret = insert(body, caret, "\n", None);
+                if let Some(p) = body.paragraphs.get_mut(caret.0) {
+                    p.level = sp.level;
+                    p.props = sp.props.clone();
+                }
+            }
+            for r in &sp.runs {
+                match r.kind {
+                    RunKind::Text => caret = insert(body, caret, &r.text, Some(r.props.clone())),
+                    RunKind::Break => caret = insert(body, caret, "\u{b}", Some(r.props.clone())),
+                    _ => {
+                        if let Some(p) = body.paragraphs.get_mut(caret.0) {
+                            let idx = split_at(p, caret.1);
+                            p.runs.insert(idx, r.clone());
+                            caret.1 += r.char_len();
+                        }
+                    }
+                }
+            }
+        }
+        caret
+    }
+
+    #[test]
+    fn paste_matches_inserting_run_by_run() {
+        let bold = |t: &str| Run::with(t, RunProps { bold: Some(true), ..Default::default() });
+        let mut src = body("");
+        src.paragraphs = vec![
+            Paragraph {
+                runs: vec![Run::with("ab", RunProps::default()), Run::with("cd", RunProps::default()), bold("ef"), bold("g")],
+                ..Default::default()
+            },
+            Paragraph {
+                runs: vec![
+                    bold("h"),
+                    Run { text: String::new(), props: RunProps::default(), kind: RunKind::Break },
+                    Run::with("i", RunProps::default()),
+                ],
+                level: 1,
+                ..Default::default()
+            },
+            Paragraph { runs: vec![Run::with("jk", RunProps::default())], ..Default::default() },
+        ];
+        for at in [0, 1, 3, 6] {
+            let mut dest = body("XYZabc");
+            format(&mut dest, (0, 2), (0, 4), &|p| p.italic = Some(true));
+            let mut want = dest.clone();
+            let want_caret = insert_body_by_runs(&mut want, (0, at), &src);
+            let caret = insert_body(&mut dest, (0, at), &src);
+            assert_eq!(caret, want_caret, "caret at {at}");
+            assert_eq!(format!("{:?}", dest.paragraphs), format!("{:?}", want.paragraphs), "paste at {at}");
+        }
+    }
+
+    #[test]
+    fn multiline_insert_splits_into_paragraphs() {
+        let mut b = body("abcd");
+        let c = insert(&mut b, (0, 2), "x\ny\u{b}z\n\nw", None);
+        assert_eq!(c, (3, 1));
+        let texts: Vec<String> = b.paragraphs.iter().map(Paragraph::text).collect();
+        assert_eq!(texts, ["abx", "y\u{b}z", "", "wcd"]);
+    }
+
     #[test]
     fn words_and_moves() {
         let b = body("Hello brave world");

crates/model/src/numfmt.rs

@@ -143,9 +143,14 @@ fn group(digits: &str, sep: char) -> String {
     out
 }
 
+/// Longest number format applied, as in Excel (255 characters); a longer one formats as
+/// General, so a chart cannot make every label expand a huge format.
+pub const MAX_CODE_LEN: usize = 255;
+
 /// `v` formatted with the Excel number format `code` in language `lang` (axis labels: the text
 /// section of a format doesn't apply).
 pub fn format(code: &str, v: f64, lang: Option<&str>) -> String {
+    let code = if code.len() > MAX_CODE_LEN * 4 || code.chars().count() > MAX_CODE_LEN { "General" } else { code };
     let (sep, dec) = marks(lang);
     if !v.is_finite() {
         return String::new();
@@ -299,6 +304,14 @@ mod tests {
 
     const RUB: &str = r#"_-* #\ ##0\ "₽"_-;\-* #\ ##0\ "₽"_-;_-* "-"??\ "₽"_-;_-@_-"#;
 
+    #[test]
+    fn an_overlong_format_is_general() {
+        let code = "0".repeat(100_000);
+        assert_eq!(format(&code, 12.5, None), format("General", 12.5, None));
+        let ok = "0".repeat(MAX_CODE_LEN);
+        assert_eq!(format(&ok, 7.0, None).len(), MAX_CODE_LEN);
+    }
+
     #[test]
     fn scientific_subnormal() {
         assert_eq!(format("0.00E+00", 5e-324, None), "4.94E-324");

crates/ogg/src/lib.rs

@@ -415,6 +415,11 @@ impl CaptureScanner {
 }
 
 fn read_parts(src: &(impl ByteSource + ?Sized), parts: &[(u64, u32)]) -> Result<Vec<u8>> {
+    // Ranges come from a scan of some source; check them against this one before sizing a buffer.
+    let len = src.len();
+    if parts.iter().any(|&(o, n)| o.checked_add(u64::from(n)).is_none_or(|end| end > len)) {
+        return Err(Error::Invalid("packet range lies outside the source".into()));
+    }
     let mut v = Vec::with_capacity(parts.iter().map(|p| p.1 as usize).sum());
     for &(o, n) in parts {
         let a = v.len();
@@ -508,6 +513,7 @@ impl OpusTiming {
                     c = timing_add(c, i64::from(durations[k]))?;
                     ends[k] = Some(c);
                 }
+                cursor = Some(c);
                 break;
             }
             let Some(g) = stream.packets[j].granule else { break };

crates/ogg/src/tests.rs

@@ -183,6 +183,27 @@ fn opus_toc_durations() {
     assert_eq!(opus_packet_samples([0xF8, 0], 0), None);
 }
 
+#[test]
+fn opus_timing_includes_packets_after_the_last_known_granule() {
+    let f = opus_file(6, 312, 0);
+    let o = open(&f).unwrap();
+    let mut stream = o.streams[0].clone();
+    // Missing granules on complete-packet pages are non-conforming. The existing recovery
+    // fallback still assigns their packet positions; total must include the same samples.
+    stream.packets.last_mut().unwrap().granule = None;
+    let timing = OpusTiming::of(&stream, 312).unwrap();
+    assert_eq!(timing.starts, vec![-312, 648, 1608, 2568, 3528, 4488]);
+    assert_eq!(timing.total, 6 * 960 - 312);
+
+    // With no usable granule, every complete packet still contributes its TOC duration.
+    for packet in &mut stream.packets {
+        packet.granule = None;
+    }
+    let timing = OpusTiming::of(&stream, 312).unwrap();
+    assert_eq!(timing.starts, vec![-312, 648, 1608, 2568, 3528, 4488]);
+    assert_eq!(timing.total, 6 * 960 - 312);
+}
+
 #[test]
 fn opus_timing_rejects_a_granule_that_overflows() {
     let packet = |granule: i64| Stream {
@@ -274,3 +295,13 @@ fn a_budget_too_small_to_search_is_spent() {
     let f = opus_file(6, 312, 0);
     assert_eq!(scanner.find(&f, 0, f.len() as u64).unwrap(), None);
 }
+
+#[test]
+fn read_packet_checks_its_ranges_against_the_source_before_allocating() {
+    let f = opus_file(10, 312, 500);
+    let o = open(&f).unwrap();
+    let s = o.stream_of(Codec::Opus).unwrap();
+    // The last packet lies past the end of a source cut short: an error, not a read of missing bytes.
+    let short = &f[..f.len() / 2];
+    assert!(matches!(o.read_packet(&short, s, 9), Err(Error::Invalid(_))));
+}

crates/pdf/src/lib.rs

@@ -307,7 +307,7 @@ pub fn master_text_pieces(pres: &Presentation, m: &deckcraft_model::Master, pape
                 .body
                 .paragraphs
                 .get(run.para)
-                .map(|p| p.runs.iter().map(|r| r.text.as_str()).collect::<String>())
+                .map(|p| p.runs.iter().map(|r| r.content()).collect::<String>())
                 .unwrap_or_default()
                 .chars()
                 .skip(run.chars.0)
@@ -522,7 +522,8 @@ impl Exporter<'_> {
         let k = b.width() / sw;
         // Raster at the requested dpi relative to the box size on paper.
         let scale = raster_scale(b.width(), (sw, sh), self.opts.dpi);
-        let ropts = RenderOpts { scale, threads: 4, ..Default::default() };
+        // One clock reading for the raster and the text layer, so a date field cannot differ between them.
+        let ropts = RenderOpts { scale, threads: 4, now: deckcraft_text::datetime::DateTime::now_local(), ..Default::default() };
         // Two rasters per slide: the backdrop (background, master and layout graphics) is the same
         // on every slide that shares its layout, so the writer stores it once, and the slide's own
         // shapes draw over it (#845).
@@ -563,7 +564,7 @@ impl Exporter<'_> {
         }
         if self.opts.text_layer {
             let view = Affine::translate((b.x0, b.y0)) * Affine::scale(k);
-            for pt in deckcraft_render::place_slide(pres, i).texts {
+            for pt in deckcraft_render::place_slide_with(pres, i, &ropts).texts {
                 self.text_layer(s, &pt, view, false)?;
             }
             let _ = sh;
@@ -581,7 +582,7 @@ impl Exporter<'_> {
                 .body
                 .paragraphs
                 .get(run.para)
-                .map(|p| p.runs.iter().map(|r| r.text.as_str()).collect::<String>())
+                .map(|p| p.runs.iter().map(|r| r.content()).collect::<String>())
                 .unwrap_or_default()
                 .chars()
                 .skip(run.chars.0)

crates/pdf/src/tests.rs

@@ -269,8 +269,6 @@ fn unembeddable_font_returns_error_instead_of_a_pdf_missing_text() {
 #[cfg_attr(not(target_arch = "wasm32"), test)]
 fn supported_unicode_is_shaped_and_recovered_from_the_page_text_layer() {
     use deckcraft_model::{Shape, ShapeId, Xfrm};
-    use hayro_syntax::content::ops::TypedInstruction;
-    use hayro_syntax::object::{Dict, Object, Stream};
 
     let text = "Café Ελληνικά Привет";
     let face = FontDb::global().face("Ubuntu", "Regular");
@@ -292,8 +290,17 @@ fn supported_unicode_is_shaped_and_recovered_from_the_page_text_layer() {
     assert!(runs.iter().all(|run| run.face.family == "Ubuntu" && !run.glyphs.is_empty() && run.glyphs.iter().all(|glyph| glyph.0 != 0)));
 
     let bytes = export(&p, &opts(PageLayout::Slides)).unwrap();
-    let pdf = hayro_syntax::Pdf::new(bytes.clone()).unwrap();
-    let page = &pdf.pages()[0];
+    assert_eq!(page_text(&bytes, 0), text);
+}
+
+/// The text of page `index`, read the way a PDF reader does: the content stream's text-showing
+/// operators decoded through the page font's ToUnicode map.
+fn page_text(bytes: &[u8], index: usize) -> String {
+    use hayro_syntax::content::ops::TypedInstruction;
+    use hayro_syntax::object::{Dict, Object, Stream};
+
+    let pdf = hayro_syntax::Pdf::new(bytes.to_vec()).unwrap();
+    let page = &pdf.pages()[index];
     let resources = page.raw().get::<Dict<'_>>(b"Resources").unwrap();
     let fonts = resources.get::<Dict<'_>>(b"Font").unwrap();
     assert_eq!(fonts.len(), 1);
@@ -344,7 +351,51 @@ fn supported_unicode_is_shaped_and_recovered_from_the_page_text_layer() {
             _ => {}
         }
     }
-    assert_eq!(extracted, text);
+    extracted
+}
+
+fn ubuntu_runs(runs: Vec<deckcraft_model::text::Run>) -> TextBody {
+    let paragraph = deckcraft_model::text::Paragraph { runs, ..Default::default() };
+    let mut body = TextBody { paragraphs: vec![paragraph], ..Default::default() };
+    for run in &mut body.paragraphs[0].runs {
+        run.props.font = Some("Ubuntu".into());
+        run.props.size = Some(20.0);
+    }
+    body
+}
+
+fn deck_with_body(n: usize, body: TextBody) -> Presentation {
+    use deckcraft_model::{Shape, ShapeId, Xfrm};
+    let mut p = deck(n);
+    for slide in &mut p.slides {
+        Arc::make_mut(slide).shapes =
+            vec![Shape { id: ShapeId(9001), xfrm: Some(Xfrm::new(20.0, 20.0, 920.0, 100.0)), text: Some(body.clone()), ..Default::default() }];
+    }
+    p
+}
+
+#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test::wasm_bindgen_test)]
+#[cfg_attr(not(target_arch = "wasm32"), test)]
+fn slide_number_field_is_recovered_from_the_page_text_layer() {
+    use deckcraft_model::text::{Run, RunKind};
+    let mut field = Run::new("<#>");
+    field.kind = RunKind::Field { field: "slidenum".into() };
+    let p = deck_with_body(3, ubuntu_runs(vec![Run::new("Page "), field]));
+    let bytes = export(&p, &opts(PageLayout::Slides)).unwrap();
+    for (i, want) in ["Page 1", "Page 2", "Page 3"].into_iter().enumerate() {
+        assert_eq!(page_text(&bytes, i), want);
+    }
+}
+
+#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test::wasm_bindgen_test)]
+#[cfg_attr(not(target_arch = "wasm32"), test)]
+fn line_break_keeps_the_text_layer_aligned_with_the_layout() {
+    use deckcraft_model::text::{Run, RunKind};
+    let mut brk = Run::new("");
+    brk.kind = RunKind::Break;
+    let p = deck_with_body(1, ubuntu_runs(vec![Run::new("one"), brk, Run::new("two")]));
+    let bytes = export(&p, &opts(PageLayout::Slides)).unwrap();
+    assert_eq!(page_text(&bytes, 0), "onetwo");
 }
 
 /// Notes pages and handouts print on the chosen paper, landscape included, with every slide box

crates/pptx/src/opc.rs

@@ -171,6 +171,7 @@ fn rels_of(doc: &xml::Doc, part: &str) -> Rels {
         let external = r.attr("TargetMode").is_some_and(|m| m.eq_ignore_ascii_case("external"));
         let target_raw = target.to_string();
         let target = if external { target_raw.clone() } else { resolve(&base, target) };
+        out.by_id.entry(id.to_string()).or_insert(out.items.len());
         out.items.push(Rel {
             id: id.to_string(),
             kind: ty.rsplit('/').next().unwrap_or(ty).to_string(),
@@ -211,11 +212,13 @@ pub struct Rel {
 #[derive(Clone, Debug, Default)]
 pub struct Rels {
     pub items: Vec<Rel>,
+    /// Id → index of its first relationship in `items`.
+    by_id: HashMap<String, usize>,
 }
 
 impl Rels {
     pub fn get(&self, id: &str) -> Option<&Rel> {
-        self.items.iter().find(|r| r.id == id)
+        self.by_id.get(id).and_then(|&i| self.items.get(i))
     }
     pub fn target(&self, id: &str) -> Option<&str> {
         self.get(id).map(|r| r.target.as_str())
@@ -339,23 +342,29 @@ pub fn relative(from: &str, to: &str) -> String {
 #[derive(Default)]
 pub struct RelsOut {
     pub items: Vec<(String, String, String, bool)>,
+    /// (type, target, external) → id of the relationship [`RelsOut::add`] made for it.
+    added: HashMap<(String, String, bool), String>,
 }
 
 impl RelsOut {
     /// Add (or reuse) a relationship; `kind` is a full type URI or a suffix of the standard base.
     pub fn add(&mut self, kind: &str, target: &str, external: bool) -> String {
         let ty = if kind.starts_with("http") { kind.to_string() } else { format!("{RT_BASE}{kind}") };
-        if let Some((id, ..)) = self.items.iter().find(|(_, t, tg, e)| *t == ty && tg == target && *e == external) {
+        let key = (ty, target.to_string(), external);
+        if let Some(id) = self.added.get(&key) {
             return id.clone();
         }
         let id = format!("rId{}", self.items.len() + 1);
-        self.items.push((id.clone(), ty, target.to_string(), external));
+        self.items.push((id.clone(), key.0.clone(), key.1.clone(), external));
+        self.added.insert(key, id.clone());
         id
     }
     /// Always add a new relationship even if an identical one exists.
     pub fn add_new(&mut self, kind: &str, target: &str, external: bool) -> String {
         let ty = if kind.starts_with("http") { kind.to_string() } else { format!("{RT_BASE}{kind}") };
         let id = format!("rId{}", self.items.len() + 1);
+        // `add` reuses the first relationship for a target, whichever call made it.
+        self.added.entry((ty.clone(), target.to_string(), external)).or_insert_with(|| id.clone());
         self.items.push((id.clone(), ty, target.to_string(), external));
         id
     }
@@ -500,6 +509,27 @@ mod tests {
         assert!(p.get("e").is_some());
     }
 
+    #[test]
+    fn many_relationships_are_found_by_index_and_first_id_wins() {
+        let n = 50_000;
+        let mut x = String::from(r#"<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">"#);
+        for i in 0..n {
+            x.push_str(&format!(r#"<Relationship Id="rId{i}" Type="{RT_BASE}image" Target="../media/image{i}.png"/>"#));
+        }
+        x.push_str(&format!(r#"<Relationship Id="rId0" Type="{RT_BASE}image" Target="../media/dup.png"/></Relationships>"#));
+        let rels = rels_from_bytes(x.as_bytes(), "ppt/slides/slide1.xml");
+        assert_eq!(rels.target("rId0"), Some("ppt/media/image0.png"), "the first of a repeated id wins");
+        assert!((0..n).all(|i| rels.target(&format!("rId{i}")) == Some(&*format!("ppt/media/image{i}.png"))));
+
+        let mut out = RelsOut::default();
+        let ids: Vec<String> = (0..n).map(|i| out.add("hyperlink", &format!("https://example.com/{i}"), true)).collect();
+        assert_eq!(out.add("hyperlink", "https://example.com/7", true), ids[7], "an identical target reuses its id");
+        assert_eq!(out.add("hyperlink", "https://example.com/7", false), format!("rId{}", n + 1), "internal is distinct");
+        let fresh = out.add_new("image", "../media/a.png", false);
+        assert_ne!(out.add_new("image", "../media/a.png", false), fresh);
+        assert_eq!(out.add("image", "../media/a.png", false), fresh, "add reuses the first add_new made");
+    }
+
     #[test]
     fn backslash_zip_entry_names_are_found() {
         let z = zip_of(&[("PPT\\Slides\\Slide1.xml", 3)]);

crates/pptx/src/read.rs

@@ -46,6 +46,9 @@ pub struct Imp<'a> {
     pub tag_bytes: usize,
     /// The tag budget ran out and the warning was given.
     pub tags_capped: bool,
+    /// Whether a part has relationships of its own, by normalized part name: looked up once
+    /// however many embedded objects point at the part.
+    pub has_rels: HashMap<String, bool>,
 }
 
 impl Imp<'_> {
@@ -446,6 +449,7 @@ pub fn import_theme(bytes: &[u8]) -> Result<(deckcraft_model::theme::Theme, Vec<
         tags_by_part: HashMap::new(),
         tag_bytes: 0,
         tags_capped: false,
+        has_rels: HashMap::new(),
     };
     let part = Part::new(&pkg, &theme_path, &doc);
     let theme = theme::read_theme(&mut imp, &part, &doc.root);
@@ -487,6 +491,7 @@ pub fn import_checked(bytes: &[u8]) -> Result<(Presentation, Vec<String>), PptxE
         tags_by_part: HashMap::new(),
         tag_bytes: 0,
         tags_capped: false,
+        has_rels: HashMap::new(),
     };
     // Slide ids first so hyperlinks anywhere can point at slides.
     let slide_ids = register_slides(&mut imp, &docs, &slide_entries, &mut lost_slides);
@@ -663,52 +668,55 @@ fn read_slides(
     let pkg = imp.pkg;
     let fallback_layout = p.masters.first().and_then(|m| m.layouts.first()).map(|l| l.id).unwrap_or_default();
     let mut file_slide_ids: HashMap<u32, SlideId> = HashMap::new();
-    let mut notes_by_target: HashMap<String, TextBody> = HashMap::new();
+    // A notes or comments part belongs to one slide; one shared by many must not be read (and
+    // copied) once per slide that names it.
+    let mut owned_parts: HashSet<String> = HashSet::new();
     for (file_id, path, id) in slide_ids {
         let Some(doc) = docs.get(&opc::norm(path)) else { continue };
         let part = Part::new(pkg, path, doc);
         let layout = part.rels.first_of("slideLayout").and_then(|r| layout_by_part.get(&opc::norm(&r.target)).copied()).unwrap_or(fallback_layout);
         let mut slide = read_slide(imp, &part, doc, *id, layout);
-        if let Some(notes) = slide_notes(imp, &part, &mut notes_by_target) {
+        if let Some(notes) = slide_notes(imp, &part, &mut owned_parts) {
             slide.notes = notes;
         }
-        read_slide_comments(pkg, pres_part, &part, &mut slide);
+        read_slide_comments(pkg, pres_part, &part, &mut slide, &mut owned_parts);
         file_slide_ids.insert(*file_id, *id);
         p.slides.push(Arc::new(slide));
     }
     file_slide_ids
 }
 
-/// The slide's notes text, read once per notes part.
-fn slide_notes(imp: &mut Imp, part: &Part, cache: &mut HashMap<String, TextBody>) -> Option<TextBody> {
+/// The slide's notes text. A notes part is the notes of the first slide that names it.
+fn slide_notes(imp: &mut Imp, part: &Part, owned: &mut HashSet<String>) -> Option<TextBody> {
     let n = part.rels.first_of("notesSlide")?;
-    let key = opc::norm(&n.target);
-    if let Some(cached) = cache.get(&key) {
-        return Some(cached.clone());
+    if !owned.insert(opc::norm(&n.target)) {
+        log::warn!("pptx: notes part {} is named by more than one slide; kept on the first", n.target);
+        return None;
     }
     let pkg = imp.pkg;
     let nd = load(pkg, &n.target)?;
     let np = Part::new(pkg, &n.target, &nd);
-    let notes = read_notes(imp, &np, &nd.root);
-    cache.insert(key, notes.clone());
-    Some(notes)
+    Some(read_notes(imp, &np, &nd.root))
 }
 
 /// Comments. A modern part and the legacy part can describe the same threads (PowerPoint
 /// writes both): the modern one wins, its flattened legacy copy is skipped.
-fn read_slide_comments(pkg: &Package, pres_part: &Part, part: &Part, slide: &mut Slide) {
-    let mut parts: Vec<(Doc, bool)> = vec![];
+/// Each comments part is read once, for the first slide that names it.
+fn read_slide_comments(pkg: &Package, pres_part: &Part, part: &Part, slide: &mut Slide, owned: &mut HashSet<String>) {
+    let mut parts: Vec<(Doc, bool, bool)> = vec![];
     for c in part.rels.all_of("comments") {
+        // An already-owned part is not re-read, but its kind still decides modern precedence.
+        let fresh = owned.insert(opc::norm(&c.target));
         if let Some(cd) = pkg.xml(&c.target) {
             // The content type names the modern part; a package that types it only through a
             // Default entry instead of an Override is still modern when its root is p188.
             let modern = pkg.content_type(&c.target).as_deref() == Some(crate::write::CT_COMMENTS_MODERN) || cd.root.prefix() == "p188";
-            parts.push((cd, modern));
+            parts.push((cd, modern, fresh));
         }
     }
-    let has_modern = parts.iter().any(|(_, m)| *m);
-    for (cd, modern) in parts {
-        if has_modern && !modern {
+    let has_modern = parts.iter().any(|(_, m, _)| *m);
+    for (cd, modern, fresh) in parts {
+        if !fresh || (has_modern && !modern) {
             continue;
         }
         slide.comments.extend(read_comments(pkg, pres_part, &cd.root, modern));
@@ -1343,6 +1351,7 @@ fn read_show(sp: &El, shows: &HashMap<String, String>) -> ShowSettings {
         without_narration: sp.bool("showNarration") == Some(false),
         without_animation: sp.bool("showAnimation") == Some(false),
         use_timings: sp.bool("useTimings").unwrap_or(true),
+        show_media_controls: sp.find("showMediaCtrls").and_then(|e| e.bool("val")).unwrap_or(true),
         ..Default::default()
     };
     if sp.child("browse").is_some() {

crates/pptx/src/read/dml.rs

@@ -664,12 +664,22 @@ fn push_text_runs(para: &mut Paragraph, props: RunProps, text: &str) {
 /// Appends an Office Math (a14:m) run: its plain text and its OMML.
 fn push_math_run(para: &mut Paragraph, part: &Part, e: &El) {
     if para.runs.len() < MAX_PARAGRAPH_RUNS {
-        let mut text = String::new();
-        let mut ts = vec![];
-        e.find_all("t", &mut ts);
-        for t in ts {
-            text.push_str(&t.text());
+        // The text of the outermost `t` elements: a `t` nested in another is already part of
+        // the outer one's text, and taking it again would copy it once per nesting level.
+        fn outer_t(e: &El, depth: usize, text: &mut String) {
+            if depth > crate::xml::MAX_DEPTH {
+                return;
+            }
+            for c in e.elements() {
+                if c.is("t") {
+                    text.push_str(&c.text());
+                } else {
+                    outer_t(c, depth + 1, text);
+                }
+            }
         }
+        let mut text = String::new();
+        outer_t(e, 0, &mut text);
         let omml = e.elements().map(|c| part.keep_inner(c)).collect::<String>();
         para.runs.push(Run { text, props: RunProps::default(), kind: RunKind::Math { omml } });
     }
@@ -714,6 +724,17 @@ mod tests {
     use super::*;
     use crate::xml::parse;
 
+    #[test]
+    fn nested_math_text_is_taken_once() {
+        // 200 `m:t` nested in each other around one word: the word, not 200 copies of it.
+        let x = format!(r#"<a14:m xmlns:a14="a" xmlns:m="m"><m:oMath>{}word{}</m:oMath></a14:m>"#, "<m:t>".repeat(200), "</m:t>".repeat(200));
+        let d = parse(x.as_bytes()).unwrap();
+        let part = Part { name: "ppt/slides/slide1.xml".into(), rels: Default::default(), ns: vec![], inner_ns: vec![] };
+        let mut para = Paragraph::default();
+        push_math_run(&mut para, &part, &d.root);
+        assert_eq!(para.runs[0].text, "word");
+    }
+
     #[test]
     fn colors_and_transforms() {
         let d = parse(

crates/pptx/src/read/shapes.rs

@@ -475,7 +475,8 @@ fn frame(imp: &mut Imp, part: &Part, ctx: &mut IdCtx, e: &El, depth: usize) -> S
         .into_iter()
         .map(|id| {
             let rel = part.rels.get(&id).filter(|r| !r.external)?;
-            if !imp.pkg.rels(&rel.target).items.is_empty() {
+            let pkg = imp.pkg;
+            if *imp.has_rels.entry(crate::opc::norm(&rel.target)).or_insert_with(|| !pkg.rels(&rel.target).items.is_empty()) {
                 return None;
             }
             let (kind, target) = (rel.ty.clone(), rel.target.clone());

crates/pptx/src/tables.rs

@@ -210,13 +210,20 @@ pub fn table_styles_xml(used: &[String], defs: &[deckcraft_model::table::TableSt
     let mut w = W::new();
     w.open("a:tblStyleLst", A::new().a("xmlns:a", NS_A).a("def", "{5C22544A-7EE6-4342-B048-85BDC9FD1C3A}"));
     let names = deckcraft_model::table::table_styles();
-    let mut done: Vec<&str> = vec![];
+    // Indexes instead of scans: written ids (as given and ASCII lower-case), and the file's
+    // definitions by lower-case id (the first wins).
+    let mut done: std::collections::HashSet<&str> = std::collections::HashSet::new();
+    let mut done_lower: std::collections::HashSet<String> = std::collections::HashSet::new();
+    let mut def_of: std::collections::HashMap<String, &deckcraft_model::table::TableStyleDef> = std::collections::HashMap::new();
+    for d in defs {
+        def_of.entry(d.id.to_ascii_lowercase()).or_insert(d);
+    }
     for s in used {
-        if done.contains(&s.as_str()) {
+        if !done.insert(s.as_str()) {
             continue;
         }
-        done.push(s);
-        if let Some(d) = defs.iter().find(|d| d.id.eq_ignore_ascii_case(s))
+        done_lower.insert(s.to_ascii_lowercase());
+        if let Some(d) = def_of.get(&s.to_ascii_lowercase())
             && crate::xml::parse(d.raw.as_bytes()).is_ok_and(|x| x.root.is("tblStyle"))
         {
             w.raw(&d.raw);
@@ -231,11 +238,11 @@ pub fn table_styles_xml(used: &[String], defs: &[deckcraft_model::table::TableSt
     }
     // Styles the file defined but no table uses still belong to the deck.
     for d in defs {
-        if done.iter().any(|s| s.eq_ignore_ascii_case(&d.id)) {
+        if done_lower.contains(&d.id.to_ascii_lowercase()) {
             continue;
         }
         if crate::xml::parse(d.raw.as_bytes()).is_ok_and(|x| x.root.is("tblStyle")) {
-            done.push(&d.id);
+            done_lower.insert(d.id.to_ascii_lowercase());
             w.raw(&d.raw);
         }
     }

crates/pptx/src/write.rs

@@ -53,6 +53,8 @@ pub struct Exp<'a> {
     pub p: &'a Presentation,
     pub pkg: PackageOut,
     media_parts: HashMap<MediaId, String>,
+    /// Each media id's item in `p.media` (the first with the id, as `Presentation::media`).
+    media_at: HashMap<MediaId, usize>,
     n_image: u32,
     n_media: u32,
     n_chart: u32,
@@ -63,6 +65,8 @@ pub struct Exp<'a> {
     n_kept: u32,
     pub slide_parts: HashMap<SlideId, String>,
     pub table_styles: Vec<String>,
+    /// The ids in `table_styles`, for checking membership without a scan.
+    pub table_style_set: std::collections::HashSet<String>,
     placeholder: Option<String>,
 }
 
@@ -119,12 +123,17 @@ fn ext_for(content_type: &str, name: &str, data: &[u8]) -> String {
     if !e.is_empty() && e.len() <= 5 && e.chars().all(|c| c.is_ascii_alphanumeric()) { e } else { "bin".into() }
 }
 
-impl Exp<'_> {
+impl<'a> Exp<'a> {
+    /// The media item `id`, found through the index rather than a scan of every item.
+    pub fn media(&self, id: MediaId) -> Option<&'a deckcraft_model::MediaItem> {
+        let p: &'a Presentation = self.p;
+        self.media_at.get(&id).and_then(|&i| p.media.get(i))
+    }
     fn media_part(&mut self, id: MediaId) -> Option<String> {
         if let Some(p) = self.media_parts.get(&id) {
             return Some(p.clone());
         }
-        let m = self.p.media(id)?;
+        let m = self.media(id)?;
         if m.data.is_empty() {
             return None;
         }
@@ -147,7 +156,7 @@ impl Exp<'_> {
     }
     /// A relationship from `o` to a media item (embedded part, or external link).
     pub fn media_rel(&mut self, o: &mut Out, id: MediaId, kind: &str) -> Option<String> {
-        let m = self.p.media(id)?;
+        let m = self.media(id)?;
         if m.data.is_empty() {
             let link = m.link.clone()?;
             return Some(o.rels.add(kind, &link, true));
@@ -156,7 +165,7 @@ impl Exp<'_> {
         Some(o.rels.add(kind, &opc::relative(&o.name, &part), false))
     }
     pub fn media_rel_new(&mut self, o: &mut Out, id: MediaId, kind: &str) -> Option<String> {
-        let m = self.p.media(id)?;
+        let m = self.media(id)?;
         if m.data.is_empty() {
             return None;
         }
@@ -489,7 +498,8 @@ fn valid_date(s: &str) -> bool {
 /// A copy of the presentation with every slide pointing at a layout that exists.
 fn sanitized(p: &Presentation) -> std::borrow::Cow<'_, Presentation> {
     let mut need = p.masters.is_empty() || p.masters.iter().any(|m| m.layouts.is_empty());
-    need |= p.slides.iter().any(|s| p.layout(s.layout).is_none());
+    let layouts: std::collections::HashSet<_> = p.masters.iter().flat_map(|m| m.layouts.iter().map(|l| l.id)).collect();
+    need |= p.slides.iter().any(|s| !layouts.contains(&s.layout));
     if !need {
         return std::borrow::Cow::Borrowed(p);
     }
@@ -532,6 +542,13 @@ pub fn export(p: &Presentation, main_ct: &str) -> Result<Vec<u8>, PptxError> {
         p,
         pkg: PackageOut::default(),
         media_parts: HashMap::new(),
+        media_at: {
+            let mut m = HashMap::new();
+            for (i, item) in p.media.iter().enumerate() {
+                m.entry(item.id).or_insert(i);
+            }
+            m
+        },
         n_image: 0,
         n_media: 0,
         n_chart: 0,
@@ -541,6 +558,7 @@ pub fn export(p: &Presentation, main_ct: &str) -> Result<Vec<u8>, PptxError> {
         n_kept: 0,
         slide_parts: HashMap::new(),
         table_styles: vec![],
+        table_style_set: Default::default(),
         placeholder: None,
     };
     for (i, s) in p.slides.iter().enumerate() {
@@ -959,9 +977,16 @@ fn section_slides(p: &Presentation) -> Vec<(String, Vec<usize>)> {
     if out.is_empty() {
         return out;
     }
+    // Each slide's first section, found once: a section may name a slide many times.
+    let mut first: HashMap<SlideId, usize> = HashMap::new();
+    for (k, sec) in p.sections.iter().enumerate() {
+        for id in &sec.slides {
+            first.entry(*id).or_insert(k);
+        }
+    }
     let mut cur = 0usize;
     for (i, s) in p.slides.iter().enumerate() {
-        if let Some(k) = p.sections.iter().position(|sec| sec.slides.contains(&s.id))
+        if let Some(&k) = first.get(&s.id)
             && k >= cur
         {
             cur = k;
@@ -1027,7 +1052,7 @@ fn write_embedded_fonts(x: &mut Exp, o: &mut Out) -> Vec<WrittenFont> {
         if let Some(rid) = seen_part.get(&id) {
             return Some(rid.clone());
         }
-        let m = x.p.media(id)?;
+        let m = x.media(id)?;
         if m.data.is_empty() || m.data.len() > 32 * 1024 * 1024 {
             return None;
         }
@@ -1181,6 +1206,14 @@ fn pres_props_xml(p: &Presentation) -> Vec<u8> {
     w.open0("p:penClr");
     w.val("a:srgbClr", s.pen_color.hex());
     w.close("p:penClr");
+    if !s.show_media_controls {
+        // "Show media controls" is PowerPoint's p14 extension; absent means shown.
+        w.open0("p:extLst");
+        w.open("p:ext", A::new().a("uri", "{2FDB2607-1784-4EEB-B798-7EB5836EED8A}"));
+        w.empty("p14:showMediaCtrls", A::new().a("xmlns:p14", NS_P14).a("val", 0));
+        w.close("p:ext");
+        w.close("p:extLst");
+    }
     w.close("p:showPr");
     w.close("p:presentationPr");
     w.finish()

crates/pptx/src/write/dml.rs

@@ -100,7 +100,7 @@ pub fn fill(w: &mut W, x: &mut Exp, o: &mut Out, f: &Fill) {
 pub fn blip_fill(w: &mut W, x: &mut Exp, o: &mut Out, tag: &str, pf: &PictureFill) {
     // An image that lives outside the package is a linked picture: `a:blip` names it through
     // `r:link`; `r:embed` may only reference a part inside the package.
-    let linked = x.p.media(pf.media).is_some_and(|m| m.data.is_empty() && m.link.is_some());
+    let linked = x.media(pf.media).is_some_and(|m| m.data.is_empty() && m.link.is_some());
     let rid = x.media_rel(o, pf.media, "image").unwrap_or_else(|| x.placeholder_rel(o));
     w.open(tag, A::new().a("rotWithShape", if pf.upright { "0" } else { "1" }));
     let adj = &pf.adjust;
@@ -449,7 +449,7 @@ pub fn hyperlink(w: &mut W, x: &mut Exp, o: &mut Out, tag: &str, h: &Hyperlink)
         return;
     };
     w.open(tag, attrs);
-    let name = x.p.media(sound_id).map(|m| sound_label(&m.name)).unwrap_or_else(|| "sound.wav".into());
+    let name = x.media(sound_id).map(|m| sound_label(&m.name)).unwrap_or_else(|| "sound.wav".into());
     w.empty("a:snd", A::new().a("r:embed", sound_rid).a("name", name));
     w.close(tag);
 }
@@ -601,7 +601,7 @@ pub fn ppr(w: &mut W, x: &mut Exp, o: &mut Out, tag: &str, level: Option<u8>, p:
         Some(Bullet::Picture { media }) => match x.media_rel(o, *media, "image") {
             Some(rid) => {
                 w.open0("a:buBlip");
-                let a = if x.p.media(*media).is_some_and(|m| m.data.is_empty() && m.link.is_some()) {
+                let a = if x.media(*media).is_some_and(|m| m.data.is_empty() && m.link.is_some()) {
                     A::new().a("r:link", &rid)
                 } else {
                     A::new().a("r:embed", &rid)
@@ -762,17 +762,27 @@ pub fn text_body(w: &mut W, x: &mut Exp, o: &mut Out, tag: &str, tb: &TextBody,
 }
 
 fn run_text(w: &mut W, x: &mut Exp, o: &mut Out, text: &str, props: &RunProps) {
+    // The run's properties are the same for every piece and line break: serialize them once.
+    let mut rpr_xml: Option<String> = None;
+    let mut put_rpr = |w: &mut W| match &rpr_xml {
+        Some(xml) => w.s.push_str(xml),
+        None => {
+            let start = w.s.len();
+            rpr(w, x, o, "a:rPr", props);
+            rpr_xml = Some(w.s[start..].to_string());
+        }
+    };
     for (i, piece) in text.split(['\n', '\u{b}']).enumerate() {
         if i > 0 {
             w.open0("a:br");
-            rpr(w, x, o, "a:rPr", props);
+            put_rpr(w);
             w.close("a:br");
         }
         if piece.is_empty() && i > 0 {
             continue;
         }
         w.open0("a:r");
-        rpr(w, x, o, "a:rPr", props);
+        put_rpr(w);
         w.elt("a:t", piece);
         w.close("a:r");
     }

crates/pptx/src/write/shapes.rs

@@ -446,7 +446,7 @@ pub fn shape(w: &mut W, x: &mut Exp, o: &mut Out, cx: &mut Ctx, s: &Shape, depth
 }
 
 fn model_rel(x: &mut Exp, o: &mut Out, media: deckcraft_model::MediaId) -> Option<String> {
-    if x.p.media(media).is_none_or(|m| m.data.is_empty()) {
+    if x.media(media).is_none_or(|m| m.data.is_empty()) {
         return None;
     }
     x.media_rel(o, media, crate::opc::RT_MODEL3D)
@@ -479,7 +479,7 @@ fn write_model(
         return;
     };
     let id = cx.id_for(s);
-    let poster = poster.filter(|p| x.p.media(*p).is_some_and(|m| !m.data.is_empty()));
+    let poster = poster.filter(|p| x.media(*p).is_some_and(|m| !m.data.is_empty()));
     let Some(poster) = poster else {
         write_model_part(w, x, o, id, s, &rid);
         return;
@@ -700,7 +700,7 @@ fn table(w: &mut W, x: &mut Exp, o: &mut Out, t: &Table) {
     t.normalize();
     w.open0("a:tbl");
     let (guid, _) = crate::tables::guid_for_style(&t.style);
-    if !x.table_styles.contains(&t.style) {
+    if x.table_style_set.insert(t.style.clone()) {
         x.table_styles.push(t.style.clone());
     }
     w.open(
@@ -884,7 +884,7 @@ fn opaque(
         p.name = label.to_string();
     }
     match preview {
-        Some(m) if x.p.media(m).is_some() => {
+        Some(m) if x.media(m).is_some() => {
             p.kind = ShapeKind::Picture { fill: deckcraft_model::style::PictureFill { media: m, ..Default::default() } };
             p.ph = None;
             shape_with_id(w, x, o, cx, &p, id);

crates/pptx/src/write/timing.rs

@@ -1,7 +1,7 @@
 //! Transitions and the animation timing tree.
 
 use deckcraft_model::anim::{AnimClass, AnimStart, Animation, BuildRole, TextBuild, Transition, build_filled, paragraph_build_roles};
-use deckcraft_model::{Shape, ShapeId, ShapeKind, find_shape};
+use deckcraft_model::{Shape, ShapeId, ShapeKind};
 
 use super::shapes::IdMap;
 use super::{Exp, Out};
@@ -16,7 +16,7 @@ pub fn transition(w: &mut W, x: &mut Exp, o: &mut Out, t: &Transition) {
         601..=900 => "med",
         _ => "slow",
     };
-    let sound = t.sound.and_then(|m| x.media_rel(o, m, "audio").map(|r| (r, x.p.media(m).map(|i| i.name.clone()).unwrap_or_default())));
+    let sound = t.sound.and_then(|m| x.media_rel(o, m, "audio").map(|r| (r, x.media(m).map(|i| i.name.clone()).unwrap_or_default())));
     let snd = |w: &mut W| {
         if let Some((r, name)) = &sound {
             w.open0("p:sndAc");
@@ -577,6 +577,21 @@ fn click_pars(w: &mut W, x: &mut Exp, ids: &mut Ids, clicks: &Groups, interactiv
     }
 }
 
+/// Most effects one slide's timing writes; animations past it are left out.
+const MAX_EFFECTS: usize = 100_000;
+
+/// The shapes of the tree by id, the first in document order for a repeated id (as `find_shape`
+/// finds it), so each animation resolves its shape without a tree walk.
+fn shape_index<'a>(shapes: &'a [Shape], depth: usize, out: &mut std::collections::HashMap<ShapeId, &'a Shape>) {
+    if depth > 64 {
+        return;
+    }
+    for s in shapes {
+        out.entry(s.id).or_insert(s);
+        shape_index(s.children(), depth + 1, out);
+    }
+}
+
 /// Write `p:timing` for a slide's animations.
 pub fn timing(w: &mut W, x: &mut Exp, anims: &[Animation], shapes: &[Shape], idmap: &IdMap) {
     let mut grp_count: std::collections::HashMap<u32, u32> = Default::default();
@@ -585,16 +600,31 @@ pub fn timing(w: &mut W, x: &mut Exp, anims: &[Animation], shapes: &[Shape], idm
     let mut bld: Vec<(u32, u32, bool)> = vec![];
     // The last paragraph effect written: (shape, class, trigger, grpId).
     let mut prev_para: Option<(ShapeId, AnimClass, Option<ShapeId>, u32)> = None;
+    let mut by_id = std::collections::HashMap::new();
+    shape_index(shapes, 0, &mut by_id);
+    let mut roles_of: std::collections::HashMap<ShapeId, Vec<BuildRole>> = Default::default();
+    let mut effect_count = 0usize;
+    let mut warned = false;
     for a in anims.iter().take(10_000) {
+        if effect_count >= MAX_EFFECTS {
+            if !warned {
+                log::warn!("pptx: more than {MAX_EFFECTS} animation effects; the rest are left out");
+            }
+            break;
+        }
         let Some(spid) = idmap.get(a.shape) else {
             log::warn!("pptx: animation on missing shape {} skipped", a.shape);
             continue;
         };
-        let Some(shape) = find_shape(shapes, a.shape) else { continue };
+        let Some(&shape) = by_id.get(&a.shape) else { continue };
         let text_sp = matches!(shape.kind, ShapeKind::Shape) && shape.text.is_some();
         let is_text_sp = matches!(shape.kind, ShapeKind::Shape) && shape.text.as_ref().is_some_and(|t| !t.is_empty());
         let text = shape.text.as_ref().filter(|_| a.text_build == TextBuild::ByParagraph && is_text_sp);
-        let roles = text.map(paragraph_build_roles).unwrap_or_default();
+        let no_roles = Vec::new();
+        let roles = match text {
+            Some(t) => roles_of.entry(a.shape).or_insert_with(|| paragraph_build_roles(t)),
+            None => &no_roles,
+        };
         let by_para = roles.contains(&BuildRole::Top);
         // PowerPoint keeps a shape's consecutive paragraph effects in one build (`grpId`) marked
         // `build="p"`; the reader turns them back into a by-paragraph build only if that plays them
@@ -632,11 +662,19 @@ pub fn timing(w: &mut W, x: &mut Exp, anims: &[Animation], shapes: &[Shape], idm
                     _ => continue,
                 };
                 let Ok(pi) = u32::try_from(i) else { break };
+                if effect_count + effs.len() >= MAX_EFFECTS {
+                    if !warned {
+                        log::warn!("pptx: more than {MAX_EFFECTS} animation effects; the rest are left out");
+                        warned = true;
+                    }
+                    break;
+                }
                 effs.push(Eff { a, spid, start, paragraph: Some(pi), grp });
             }
         } else {
             effs.push(Eff { a, spid, start: a.start, paragraph: a.paragraph, grp });
         }
+        effect_count += effs.len();
         if text_sp && !joins {
             bld.push((spid, grp, by_para || para_effect));
         }

crates/pptx/tests/it/comments.rs

@@ -146,6 +146,33 @@ fn comments_on_several_slides_round_trip() {
     assert_eq!(q.slides[2].comments[0].text, "Slide three");
 }
 
+/// A slide that names a modern part another slide already owns, plus its own legacy part, must
+/// not import the legacy copy: modern precedence holds even when the modern part is not re-read.
+#[test]
+fn owned_modern_part_still_suppresses_later_legacy() {
+    let mut p = deck();
+    let layout = p.slides[0].layout;
+    let s2 = defaults::new_slide(&mut p, layout).expect("slide");
+    p.slides.push(Arc::new(s2));
+    Arc::make_mut(&mut p.slides[1]).comments = vec![Comment { author: "Cara".into(), text: "Slide two".into(), ..Default::default() }];
+    let bytes = deckcraft_pptx::export(&p).expect("export");
+    let rels2 = part(&bytes, "ppt/slides/_rels/slide2.xml.rels").replace("modernComment2.xml", "modernComment1.xml");
+    let mut z = zip::ZipArchive::new(std::io::Cursor::new(&bytes)).expect("zip");
+    let mut out = zip::ZipWriter::new(std::io::Cursor::new(Vec::new()));
+    for i in 0..z.len() {
+        let mut f = z.by_index(i).expect("entry");
+        out.start_file(f.name(), zip::write::SimpleFileOptions::default()).expect("start");
+        if f.name() == "ppt/slides/_rels/slide2.xml.rels" {
+            std::io::Write::write_all(&mut out, rels2.as_bytes()).expect("write");
+        } else {
+            std::io::copy(&mut f, &mut out).expect("copy");
+        }
+    }
+    let q = deckcraft_pptx::import(&out.finish().expect("finish").into_inner()).expect("import");
+    assert_eq!(q.slides[0].comments.len(), 2);
+    assert!(q.slides[1].comments.is_empty(), "{:?}", q.slides[1].comments);
+}
+
 /// A legacy-only package (what older tools read and write) still imports: 1/8 pt positions,
 /// flattened replies.
 #[test]

crates/pptx/tests/it/export_scale.rs

@@ -0,0 +1,31 @@
+//! Export looks media, layouts, sections and table styles up by id: a deck with many of each and
+//! many references to the last ones exports in time linear in its size.
+
+use std::sync::Arc;
+
+use deckcraft_model::style::PictureFill;
+use deckcraft_model::{Section, Shape, ShapeId, ShapeKind, defaults};
+
+#[test]
+fn many_media_sections_and_table_styles_export() {
+    let mut p = defaults::new_presentation(None);
+    // 5,000 media items; 5,000 pictures of the last one.
+    let mut last = None;
+    for i in 0..5_000u32 {
+        last = p.add_media(&format!("m{i}.png"), "image/png", i.to_le_bytes().to_vec());
+    }
+    let last = last.unwrap();
+    let pic = |k: u32| Shape {
+        id: ShapeId(100_000 + k),
+        kind: ShapeKind::Picture { fill: PictureFill { media: last, ..Default::default() } },
+        ..Default::default()
+    };
+    Arc::make_mut(&mut p.slides[0]).shapes = (0..5_000).map(pic).collect();
+    // A section naming the slide 50,000 times, after 2,000 empty sections.
+    let id = p.slides[0].id;
+    p.sections = (0..2_000).map(|i| Section { name: format!("s{i}"), slides: vec![] }).collect();
+    p.sections.push(Section { name: "last".into(), slides: vec![id; 50_000] });
+    let bytes = deckcraft_pptx::export(&p).expect("export");
+    let q = deckcraft_pptx::import(&bytes).expect("import");
+    assert_eq!(q.slides[0].shapes.iter().filter(|s| matches!(s.kind, ShapeKind::Picture { .. })).count(), 5_000);
+}

crates/pptx/tests/it/main.rs

@@ -9,6 +9,7 @@ mod corpus_kinds;
 mod corpus_media;
 mod corpus_style;
 mod corpus_themes;
+mod export_scale;
 mod fills;
 mod kept_parts;
 mod locks;

crates/pptx/tests/it/malformed.rs

@@ -287,3 +287,34 @@ fn unreadable_slide_is_reported() {
     assert_eq!(lost, vec!["ppt/slides/slide2.xml".to_string()]);
     assert_eq!(deckcraft_pptx::import(&broken).expect("import").slides.len(), 1);
 }
+
+/// Many slides naming one notes part: it is read for the first slide only, not copied onto every
+/// slide that names it.
+#[test]
+fn a_shared_notes_part_is_read_once() {
+    use std::sync::Arc;
+    let mut p = defaults::new_presentation(None);
+    let layout = p.slides[0].layout;
+    for _ in 0..3 {
+        let s = defaults::new_slide(&mut p, layout).expect("slide");
+        p.slides.push(Arc::new(s));
+    }
+    for (i, s) in p.slides.iter_mut().enumerate() {
+        Arc::make_mut(s).notes = deckcraft_model::text::TextBody::from_text(&format!("notes {i}"));
+    }
+    let mut es = entries(&deckcraft_pptx::export(&p).expect("export"));
+    for (n, d) in es.iter_mut() {
+        if n.starts_with("ppt/slides/_rels/") {
+            let x = String::from_utf8(d.clone()).expect("utf8");
+            let x = x
+                .replace("notesSlide2.xml", "notesSlide1.xml")
+                .replace("notesSlide3.xml", "notesSlide1.xml")
+                .replace("notesSlide4.xml", "notesSlide1.xml");
+            *d = x.into_bytes();
+        }
+    }
+    let q = deckcraft_pptx::import(&rezip(&es)).expect("import");
+    assert_eq!(q.slides.len(), 4);
+    assert_eq!(q.slides[0].notes.text(), "notes 0");
+    assert!(q.slides[1..].iter().all(|s| s.notes.text().is_empty()), "a shared notes part is not copied");
+}

crates/pptx/tests/it/roundtrip.rs

@@ -2258,6 +2258,34 @@ fn default_durations_match_powerpoint() {
     }
 }
 
+/// Show media controls is PowerPoint's `p14:showMediaCtrls` extension inside `p:showPr`: off is
+/// written there, under its extension uri and with the p14 namespace declared on the element;
+/// on (the default) writes nothing.
+#[test]
+fn hidden_media_controls_survive_save_and_reopen() {
+    let props = |p: &Presentation| {
+        let bytes = deckcraft_pptx::export(p).expect("export");
+        let mut zip = zip::ZipArchive::new(std::io::Cursor::new(bytes)).expect("zip");
+        let mut x = String::new();
+        std::io::Read::read_to_string(&mut zip.by_name("ppt/presProps.xml").expect("presProps"), &mut x).expect("read");
+        x
+    };
+    let mut p = Presentation::default();
+    p.show.show_media_controls = false;
+    let xml = props(&p);
+    let show = xml.split("<p:showPr").nth(1).and_then(|r| r.split("</p:showPr>").next()).expect("p:showPr");
+    assert!(
+        show.contains(
+            "<p:ext uri=\"{2FDB2607-1784-4EEB-B798-7EB5836EED8A}\"><p14:showMediaCtrls xmlns:p14=\"http://schemas.microsoft.com/office/powerpoint/2010/main\" val=\"0\"/></p:ext>"
+        ),
+        "{xml}"
+    );
+    assert!(!round(&p).show.show_media_controls);
+    let default = Presentation::default();
+    assert!(!props(&default).contains("showMediaCtrls"));
+    assert!(round(&default).show.show_media_controls);
+}
+
 #[test]
 fn reflection_angles_and_skews_out_of_range_are_written_inside_the_schema() {
     let mut p = Presentation::default();

crates/render/src/chart.rs

@@ -1,5 +1,7 @@
 //! Charts: title, plot area with axes and gridlines, series marks, legend.
 
+use std::collections::HashMap;
+
 use deckcraft_color::{ColorTransform, Rgba, SchemeSlot};
 use deckcraft_model::Shape;
 use deckcraft_model::chart::{Chart, ChartType, TrendlineType, axis_scale};
@@ -85,9 +87,9 @@ fn bar_outline(ctx: &Ctx, s: &deckcraft_model::chart::Series) -> Option<(Rgba, f
 /// Paint of one bar: a `<c:dPt>` fill wins, and a single-series chart that varies colours by point uses one accent per point
 /// (not waterfalls, which are never read from a `<c:barChart>`). Pattern fills draw as patterns and
 /// `a:noFill` leaves the bar empty, as in PowerPoint.
-fn bar_paint(ctx: &Ctx, c: &Chart, si: usize, pi: usize, s: &deckcraft_model::chart::Series) -> Paint {
-    if let Some((_, f)) = s.point_fills.iter().find(|(k, _)| *k == pi) {
-        return paint_of(ctx, Some(f), series_fill(ctx, c, si, Some(s)));
+fn bar_paint(ctx: &Ctx, c: &Chart, si: usize, pi: usize, s: &deckcraft_model::chart::Series, fills: Option<&HashMap<usize, &Fill>>) -> Paint {
+    if let Some(f) = fills.and_then(|m| m.get(&pi)) {
+        return paint_of(ctx, Some(*f), series_fill(ctx, c, si, Some(s)));
     }
     if c.vary_colors && c.series.len() == 1 && s.fill.is_none() && c.kind != ChartType::Waterfall {
         return Paint::Color(series_color(ctx, c, pi));
@@ -883,6 +885,8 @@ fn draw_lines(ctx: &mut RenderContext, draw: &mut LineDrawing<'_, '_>) {
         let col = if area_kind { series_fill(rctx, c, si, Some(s)) } else { series_line(rctx, c, si, s) };
         let series_stats = s.error_bars.as_ref().map(|_| deckcraft_model::chart::SeriesStats::of(&s.values));
         let mut pts = vec![];
+        // Whether the series has any x value, found once rather than per point.
+        let any_x = s.x_values.iter().flatten().next().is_some();
         for i in 0..ncat {
             let Some(v) = s.values.get(i).copied().flatten() else { continue };
             let v = if stacked {
@@ -896,11 +900,11 @@ fn draw_lines(ctx: &mut RenderContext, draw: &mut LineDrawing<'_, '_>) {
             };
             let x = match kind {
                 ChartType::Scatter | ChartType::Bubble => {
-                    match (s.x_values.get(i).copied().flatten().and_then(to_x), s.x_values.iter().flatten().next()) {
+                    match (s.x_values.get(i).copied().flatten().and_then(to_x), any_x) {
                         (Some(x), _) => x,
                         // No x values at all: the points are numbered 1, 2, 3...
-                        (None, None) => to_x(i as f64 + 1.0).unwrap_or(plot.x0 + band * (slot(i) + 0.5)),
-                        (None, Some(_)) => continue,
+                        (None, false) => to_x(i as f64 + 1.0).unwrap_or(plot.x0 + band * (slot(i) + 0.5)),
+                        (None, true) => continue,
                     }
                 }
                 _ => plot.x0 + band * (slot(i) + 0.5),
@@ -970,6 +974,19 @@ fn draw_bars(ctx: &mut RenderContext, draw: &BarDrawing<'_, '_>) -> Vec<(f64, f6
         let group = bar + step * (n - 1.0);
         // Error bars need each series' mean and spread: worked out once, not per point.
         let stats: Vec<deckcraft_model::chart::SeriesStats> = bars.iter().map(|(_, s)| deckcraft_model::chart::SeriesStats::of(&s.values)).collect();
+        // Each series' per-point fills by point (the first for a point wins), not searched per bar.
+        let point_fills: Vec<HashMap<usize, &Fill>> = bars
+            .iter()
+            .map(|(_, s)| {
+                let mut m = HashMap::new();
+                for (k, f) in &s.point_fills {
+                    m.entry(*k).or_insert(f);
+                }
+                m
+            })
+            .collect();
+        // A waterfall's running bars, worked out once for all its categories.
+        let waterfall_bars = if waterfall { c.waterfall_bars() } else { Vec::new() };
         for i in 0..ncat {
             let mut pos_acc = 0.0;
             let mut neg_acc = 0.0;
@@ -983,7 +1000,7 @@ fn draw_bars(ctx: &mut RenderContext, draw: &BarDrawing<'_, '_>) -> Vec<(f64, f6
                 let v = s.values.get(i).copied().flatten().unwrap_or(0.0) / total;
                 let start = band * slot(i) + (band - group) / 2.0 + if stacked { 0.0 } else { step * bi as f64 };
                 let (a, b) = if waterfall {
-                    c.waterfall_bars().get(i).copied().unwrap_or_default()
+                    waterfall_bars.get(i).copied().unwrap_or_default()
                 } else if stacked {
                     if v >= 0.0 {
                         let r = (pos_acc, pos_acc + v);
@@ -1015,7 +1032,7 @@ fn draw_bars(ctx: &mut RenderContext, draw: &BarDrawing<'_, '_>) -> Vec<(f64, f6
                     };
                     Paint::Color(series_color(rctx, c, slot))
                 } else {
-                    bar_paint(rctx, c, *si, i, s)
+                    bar_paint(rctx, c, *si, i, s, point_fills.get(bi))
                 };
                 fill_with(ctx, &paint, r.abs(), m);
                 if !waterfall && let Some((oc, ow)) = bar_outline(rctx, s).filter(|o| o.1 > 0.0) {

crates/render/src/images.rs

@@ -37,7 +37,8 @@ struct Cache {
     bad_order: VecDeque<usize>,
     bad_bytes: usize,
     /// GIFs by bytes address and adjustments (`None`: not animated); the bytes stay alive with them.
-    anims: HashMap<(usize, u64), (Arc<Vec<u8>>, Option<Arc<Anim>>)>,
+    /// Decoded animations by (bytes, adjustments), each with the clock of its last use.
+    anims: HashMap<(usize, u64), (Arc<Vec<u8>>, Option<Arc<Anim>>, u64)>,
 }
 
 /// Longest side, total decoded size and frame count kept for one animated GIF; the largest canvas
@@ -432,16 +433,33 @@ fn anim(bytes: &Arc<Vec<u8>>, adj: &PictureAdjust) -> Option<Arc<Anim>> {
         return None;
     }
     let key = (Arc::as_ptr(bytes) as usize, adjust_key(adj));
-    if let Some(a) = with(|c| c.anims.get(&key).map(|e| e.1.clone())) {
+    let hit = with(|c| {
+        c.clock += 1;
+        let clock = c.clock;
+        c.anims.get_mut(&key).map(|e| {
+            e.2 = clock;
+            e.1.clone()
+        })
+    });
+    if let Some(a) = hit {
         return a;
     }
     let a = decode_anim(bytes, adj).map(Arc::new);
     with(|c| {
-        let held: usize = c.anims.values().filter_map(|e| e.1.as_ref()).map(|a| a.bytes()).sum();
-        if held + a.as_ref().map_or(0, |a| a.bytes()) > GIF_CACHE_BUDGET || c.anims.len() >= 64 {
-            c.anims.clear();
+        // Make room by dropping the least recently used animations, not every one of them, so a
+        // slide whose animations overflow the cache does not decode all of them again each frame.
+        let new = a.as_ref().map_or(0, |a| a.bytes());
+        loop {
+            let held: usize = c.anims.values().filter_map(|e| e.1.as_ref()).map(|a| a.bytes()).sum();
+            if held + new <= GIF_CACHE_BUDGET && c.anims.len() < 64 {
+                break;
+            }
+            let Some(oldest) = c.anims.iter().min_by_key(|(_, e)| e.2).map(|(k, _)| *k) else { break };
+            c.anims.remove(&oldest);
         }
-        c.anims.insert(key, (bytes.clone(), a.clone()));
+        c.clock += 1;
+        let clock = c.clock;
+        c.anims.insert(key, (bytes.clone(), a.clone(), clock));
     });
     a
 }
@@ -535,6 +553,26 @@ mod tests {
         out.into_inner()
     }
 
+    /// A two-frame GIF whose first pixel is `n`, so each one has its own bytes.
+    fn gif(n: u8) -> Arc<Vec<u8>> {
+        use image::codecs::gif::GifEncoder;
+        let frame = |c: u8| image::Frame::new(image::RgbaImage::from_pixel(2, 2, image::Rgba([n, c, 0, 255])));
+        let mut out = Vec::new();
+        GifEncoder::new(&mut out).encode_frames([frame(0), frame(255)]).expect("encode");
+        Arc::new(out)
+    }
+
+    #[test]
+    fn a_full_animation_cache_drops_the_oldest_entry_not_all_of_them() {
+        let adj = PictureAdjust::default();
+        let gifs: Vec<_> = (0..70).map(gif).collect();
+        for g in &gifs {
+            assert!(anim(g, &adj).is_some());
+        }
+        let (len, newest) = with(|c| (c.anims.len(), c.anims.contains_key(&(Arc::as_ptr(&gifs[69]) as usize, adjust_key(&adj)))));
+        assert!(newest && len >= 32, "{len} cached");
+    }
+
     #[test]
     fn rgba_conversion_is_refused_past_the_cap() {
         let png = grey_png(100, 50);

crates/render/src/lib.rs

@@ -54,7 +54,7 @@ pub use images::{decode as decode_image, gif_frame};
 pub use morph_path::PathMorph;
 pub use morph_text::TextMorph;
 pub use pattern::{is_fg as pattern_is_fg, presets as pattern_presets, tile as pattern_tile};
-pub use placed::{Placed, PlacedLink, PlacedShape, PlacedText, place_master_texts, place_slide, text_outline};
+pub use placed::{Placed, PlacedLink, PlacedShape, PlacedText, place_master_texts, place_slide, place_slide_with, text_outline};
 pub use table::cell_body as table_cell_body;
 pub use table::cell_rects as table_cell_rects;
 pub use table::row_heights as table_row_heights;

crates/render/src/morph_text.rs

@@ -76,16 +76,12 @@ fn tokens(l: &TextLayout, chars: bool) -> (Vec<Token>, Vec<(usize, usize)>) {
 
 /// For each token of `b`, the token of `a` with the same text, in reading order, each used once.
 fn matches(a: &[Token], b: &[Token]) -> Vec<Option<usize>> {
-    let mut used = vec![false; a.len()];
-    b.iter()
-        .map(|tb| {
-            let i = a.iter().enumerate().position(|(i, ta)| !used.get(i).copied().unwrap_or(true) && ta.key == tb.key)?;
-            if let Some(u) = used.get_mut(i) {
-                *u = true;
-            }
-            Some(i)
-        })
-        .collect()
+    // Unused tokens of `a` by text, in reading order, so each lookup is a pop rather than a scan.
+    let mut free: std::collections::HashMap<&str, std::collections::VecDeque<usize>> = std::collections::HashMap::new();
+    for (i, ta) in a.iter().enumerate() {
+        free.entry(ta.key.as_str()).or_default().push_back(i);
+    }
+    b.iter().map(|tb| free.get_mut(tb.key.as_str())?.pop_front()).collect()
 }
 
 fn layout(ctx: &Ctx, s: &Shape, x: Xfrm, fields: &dyn Fields) -> Option<TextLayout> {
@@ -228,3 +224,19 @@ pub(crate) fn draw(
 pub(crate) fn token_keys(l: &TextLayout, chars: bool) -> Vec<String> {
     tokens(l, chars).0.into_iter().map(|t| t.key).collect()
 }
+
+#[cfg(test)]
+mod match_tests {
+    use super::*;
+
+    fn tok(k: &str) -> Token {
+        Token { key: k.into(), glyphs: Vec::new(), origin: Point::ZERO, run: 0 }
+    }
+
+    #[test]
+    fn each_source_token_is_used_once_in_reading_order() {
+        let a: Vec<Token> = ["a", "b", "a"].map(tok).into();
+        let b: Vec<Token> = ["a", "a", "a", "b", "c"].map(tok).into();
+        assert_eq!(matches(&a, &b), vec![Some(0), Some(2), None, Some(1), None]);
+    }
+}

crates/render/src/placed.rs

@@ -2,9 +2,9 @@
 //! that put real text over a raster (PDF text layer, links) and for text extraction.
 
 use deckcraft_model::resolve::{self, Ctx};
-use deckcraft_model::text::{Hyperlink, TextBody};
+use deckcraft_model::text::{Hyperlink, RunKind, TextBody};
 use deckcraft_model::{Presentation, Shape, ShapeId, ShapeKind};
-use deckcraft_text::{Opts, TextLayout};
+use deckcraft_text::{Fields, Opts, TextLayout};
 use kurbo::{Affine, Rect};
 
 use crate::{SlideFields, shape_geometry, table};
@@ -52,10 +52,16 @@ pub struct Placed {
 
 /// Text and links of slide `index` (master and layout graphics first, as rendered).
 pub fn place_slide(pres: &Presentation, index: usize) -> Placed {
+    place_slide_with(pres, index, &crate::RenderOpts::default())
+}
+
+/// [`place_slide`] with the render options the slide was drawn with, so date fields take the same
+/// date and time as the raster (`opts.now`).
+pub fn place_slide_with(pres: &Presentation, index: usize, opts: &crate::RenderOpts) -> Placed {
     let mut out = Placed::default();
     let Some(slide) = pres.slides.get(index) else { return out };
     let Some(rctx) = Ctx::for_slide(pres, slide) else { return out };
-    let fields = SlideFields::new(pres.slide_number(index), pres.header_footer.footer_text.clone(), &crate::RenderOpts::default());
+    let fields = SlideFields::new(pres.slide_number(index), pres.header_footer.footer_text.clone(), opts);
     let (show_layout, show_master) = resolve::show_master_shapes(slide, rctx.layout);
     if show_master {
         let mctx = Ctx::for_master(pres, rctx.master);
@@ -131,9 +137,11 @@ fn place(out: &mut Placed, rctx: &Ctx, fields: &SlideFields, s: &Shape, parent:
         }
         ShapeKind::Table(t) => {
             // Cell text, laid out exactly as the table draws it.
+            // The table's style is looked up once, not once per cell.
+            let def = table::resolve_style(rctx, t);
             for (r, c, rect) in table::cell_rects(t, &table::row_heights(rctx, t, fields)) {
                 let Some(cell) = t.cell(r, c).filter(|cell| !cell.text.is_empty()) else { continue };
-                let body = table::cell_body(rctx, t, r, c, cell);
+                let body = table::cell_body_with_def(rctx, def, t, r, c, cell);
                 let tmp = Shape::table_cell(body.clone());
                 place_text(out, rctx, fields, s.id, &tmp, &body, rect, m);
             }
@@ -152,9 +160,24 @@ fn place(out: &mut Placed, rctx: &Ctx, fields: &SlideFields, s: &Shape, parent:
 fn place_text(out: &mut Placed, rctx: &Ctx, fields: &SlideFields, owner: ShapeId, s: &Shape, body: &TextBody, tr: Rect, m: Affine) {
     let layout = deckcraft_text::layout(rctx, s, body, &Opts { rect: tr, fields, prompt_color: None, no_shrink: false });
     let m = crate::text_transform(m, tr, layout.rotation);
+    // Field runs carry their saved text (`‹#›`); the layout drew their values, so the body that
+    // goes with it (character offsets, text layer) must hold the same values.
+    let mut placed = body.clone();
+    for (pi, para) in body.paragraphs.iter().enumerate() {
+        for (ri, run) in para.runs.iter().enumerate() {
+            let RunKind::Field { field } = &run.kind else { continue };
+            let lang = resolve::run(rctx, s, para, &run.props).lang;
+            if let Some(v) = fields.field_in(field, lang.as_deref())
+                && let Some(out_run) = placed.paragraphs.get_mut(pi).and_then(|p| p.runs.get_mut(ri))
+            {
+                out_run.text = v;
+                out_run.kind = RunKind::Text;
+            }
+        }
+    }
     // Text hyperlinks: one box per line segment of a linked run.
     for run in layout.runs.iter().filter(|r| r.link && !r.glyphs.is_empty()) {
-        let Some(link) = run_link(body, run.para, run.chars.0) else { continue };
+        let Some(link) = run_link(&placed, run.para, run.chars.0) else { continue };
         let Some(line) = layout.lines.iter().find(|l| l.para == run.para && l.start <= run.chars.0 && run.chars.0 <= l.end) else { continue };
         // The run's visual extent (right-to-left runs run from right to left).
         let first = run.glyphs.first().map(|g| g.1).unwrap_or(0.0);
@@ -162,7 +185,7 @@ fn place_text(out: &mut Placed, rctx: &Ctx, fields: &SlideFields, owner: ShapeId
         let r = Rect::new(x0, line.top, x1, line.bottom);
         out.links.push(PlacedLink { rect: m.transform_rect_bbox(r), link, shape: owner, text: true });
     }
-    out.texts.push(PlacedText { layout, transform: m, body: body.clone() });
+    out.texts.push(PlacedText { layout, transform: m, body: placed });
 }
 
 /// The hyperlink of the model run containing character `at` of paragraph `para`.

crates/render/src/renderer.rs

@@ -33,6 +33,10 @@ pub struct Renderer {
     /// Visits spent on outer-shadow silhouette passes, kept apart so they cannot use up the budget
     /// of the normal drawing that follows.
     shadow_work: usize,
+    /// `RenderOpts::skip` as a set, with the slice (address, length) it was built from: the
+    /// slice can be as long as the slide, and is tested for every shape drawn. Forgotten when a
+    /// frame starts, so another frame's slice at the same address is never mistaken for it.
+    skip: Option<(usize, usize, std::collections::HashSet<ShapeId>)>,
 }
 
 impl Default for Renderer {
@@ -48,6 +52,7 @@ impl Default for Renderer {
             in_shadow_pass: false,
             render_work: 0,
             shadow_work: 0,
+            skip: None,
         }
     }
 }
@@ -163,6 +168,7 @@ impl Renderer {
     pub(crate) fn slide(&mut self, pres: &Presentation, slide: &Slide, index: usize, opts: &RenderOpts) -> Image {
         self.render_work = 0;
         self.shadow_work = 0;
+        self.skip = None;
         self.in_shadow_pass = false;
         let (mut ctx, w, h, view) = Self::canvas(pres, opts, needs_filters(pres, slide));
         let f = Frame { pres, opts, fields: Self::fields(pres, index, opts) };
@@ -178,6 +184,7 @@ impl Renderer {
     pub(crate) fn slide_part(&mut self, pres: &Presentation, slide: &Slide, index: usize, part: SlidePart, opts: &RenderOpts) -> Image {
         self.render_work = 0;
         self.shadow_work = 0;
+        self.skip = None;
         self.in_shadow_pass = false;
         let (mut ctx, w, h, view) = Self::canvas(pres, opts, needs_filters(pres, slide));
         let f = Frame { pres, opts, fields: Self::fields(pres, index, opts) };
@@ -212,6 +219,7 @@ impl Renderer {
         let mix = if mix.is_finite() { mix.clamp(0.0, 1.0) } else { 1.0 };
         self.render_work = 0;
         self.shadow_work = 0;
+        self.skip = None;
         self.in_shadow_pass = false;
         let (mut ctx, w, h, view) = Self::canvas(pres, opts, needs_filters(pres, old.0) || needs_filters(pres, new.0));
         let (Some(co), Some(cn)) = (Ctx::for_slide(pres, old.0), Ctx::for_slide(pres, new.0)) else { return self.finish(ctx, w, h) };
@@ -260,6 +268,7 @@ impl Renderer {
     pub(crate) fn layout(&mut self, pres: &Presentation, mi: usize, li: Option<usize>, opts: &RenderOpts) -> Image {
         self.render_work = 0;
         self.shadow_work = 0;
+        self.skip = None;
         self.in_shadow_pass = false;
         let (w, h) = output_size(pres, opts);
         let mut ctx = RenderContext::new_with(w, h, vello_cpu::RenderSettings { num_threads: 0, ..Default::default() });
@@ -393,8 +402,25 @@ impl Renderer {
         geo
     }
 
+    /// Whether `id` is in `skip`, looked up in a set built once per frame and slice.
+    fn skipped(&mut self, skip: &[ShapeId], id: ShapeId) -> bool {
+        if skip.is_empty() {
+            return false;
+        }
+        let key = (skip.as_ptr() as usize, skip.len());
+        match &self.skip {
+            Some((p, n, set)) if (*p, *n) == key => set.contains(&id),
+            _ => {
+                let set: std::collections::HashSet<ShapeId> = skip.iter().copied().collect();
+                let hit = set.contains(&id);
+                self.skip = Some((key.0, key.1, set));
+                hit
+            }
+        }
+    }
+
     fn shape_at(&mut self, ctx: &mut RenderContext, f: &Frame, rctx: &Ctx, s: &Shape, parent: Affine, depth: usize) {
-        if depth > 32 || (s.hidden && !f.opts.show_hidden) || f.opts.skip.contains(&s.id) {
+        if depth > 32 || (s.hidden && !f.opts.show_hidden) || self.skipped(f.opts.skip, s.id) {
             return;
         }
         let work = if self.in_shadow_pass { &mut self.shadow_work } else { &mut self.render_work };

crates/render/src/stroke.rs

@@ -191,7 +191,8 @@ pub(crate) fn limit_dash_count(path: &BezPath, pat: Vec<f64>) -> Vec<f64> {
         return pat;
     }
     let len: f64 = path.segments().map(|s| s.arclen(1e-2)).sum();
-    let dashes = len / period;
+    // Every dash of the pattern counts, not each repeat of it: a custom pattern can hold many.
+    let dashes = len / period * pat.len().div_ceil(2) as f64;
     if !len.is_finite() {
         return vec![];
     }

crates/render/src/tests.rs

@@ -1,7 +1,7 @@
 use super::{
     Ctx, Fields, Fill, Image, Opts, PathMorph, Point, RENDERER, Rect, Region, RenderOpts, Renderer, Rgba, ShapeState, SlideFields, TextMorph,
     crop_dest, dpi_for_scale, gif_frame, image_dpi, images, morph_path, morph_text, needs_filters, parse_path, pasteboard_region, place_slide,
-    render_blend, render_shapes, render_slide, render_slide_drawn, slide_extent, text_transform,
+    place_slide_with, render_blend, render_shapes, render_slide, render_slide_drawn, slide_extent, text_transform,
 };
 use deckcraft_model::chart::{ChartType, Trendline, TrendlineType};
 use deckcraft_model::style::ColorRef;
@@ -2971,6 +2971,27 @@ fn empty_bullet_is_gray_only_while_editing_and_never_in_exports() {
     assert!(changed.iter().all(|(px, _)| px[0] >= 179 && px[0] == px[1] && px[1] == px[2]));
 }
 
+#[test]
+fn placed_text_holds_the_field_value_not_the_saved_placeholder() {
+    let mut p = deck_with(vec![field_shape(Some("slidenum"), "<#>")]);
+    let second = p.slides[0].clone();
+    p.slides.push(second);
+    let placed = place_slide(&p, 1);
+    assert_eq!(placed.texts.len(), 1);
+    assert_eq!(placed.texts[0].body.text(), "2");
+    // The layout was drawn from the same value, so the offsets agree with the body.
+    assert_eq!(placed.texts[0].layout.runs.iter().map(|r| r.chars.1).max(), Some(1));
+}
+
+#[test]
+fn placed_text_takes_its_date_from_the_given_render_options() {
+    use deckcraft_text::datetime::DateTime;
+    let p = deck_with(vec![field_shape(Some("datetime1"), "1/1/2000")]);
+    let at = |now: DateTime| place_slide_with(&p, 0, &RenderOpts { now: Some(now), ..Default::default() });
+    assert_eq!(at(DateTime::new(2026, 10, 9, 20, 5, 7)).texts[0].body.text(), "10/9/2026");
+    assert_eq!(at(DateTime::new(2027, 3, 4, 0, 0, 0)).texts[0].body.text(), "3/4/2027");
+}
+
 /// A chart that has no text colour of its own takes PowerPoint's default, the theme's text colour
 /// at 65 % plus 35 %: light on Nocturne's dark slides (it used to be a fixed grey, near-invisible
 /// there), 595959 grey on Harbor's light ones.

crates/render/src/tests_wild.rs

@@ -990,4 +990,37 @@ fn a_tiny_dash_on_a_huge_shape_draws_without_running_out_of_memory() {
     p.line_to((4.0e6, 0.0));
     let pat = limit_dash_count(&p, vec![1.0, 1.0]);
     assert!((4.0e6 / (pat[0] + pat[1]) - MAX_DASHES).abs() < 1.0, "{pat:?}");
+    // A custom pattern of 1,000 dashes counts each of them: the limit is on dashes drawn.
+    let pat = limit_dash_count(&p, vec![1.0; 2000]);
+    let period: f64 = pat.iter().sum();
+    assert!((4.0e6 / period * 1000.0 - MAX_DASHES).abs() < 1.0, "{}", period);
+}
+
+/// A bar chart with 20,000 points, each with its own fill, and a sparse scatter of the same size:
+/// the per-point fills and the scatter's "has any x" are looked up, not searched per point.
+#[test]
+fn many_point_fills_and_sparse_scatter_x_render() {
+    use deckcraft_model::ShapeKind;
+    use deckcraft_model::chart::{Chart, ChartType};
+    use deckcraft_model::style::Fill;
+    let n = 20_000;
+    let chart = |kind: ChartType| {
+        let mut c = Chart::sample(kind);
+        c.series.truncate(1);
+        c.categories = (0..n).map(|i| i.to_string()).collect();
+        c.series[0].values = (0..n).map(|i| Some(i as f64)).collect();
+        c
+    };
+    let mut bars = chart(ChartType::Column);
+    bars.series[0].point_fills = (0..n).rev().map(|i| (i, Fill::solid(ColorRef::rgb(Rgba::rgb(200, 0, 0))))).collect();
+    let mut scatter = chart(ChartType::Scatter);
+    scatter.series[0].x_values = (0..n).map(|i| (i + 1 == n).then_some(1.0)).collect();
+    let shape = |id: u32, c: Chart| Shape {
+        id: ShapeId(id),
+        xfrm: Some(Xfrm::new(10.0, 10.0, 400.0, 300.0)),
+        kind: ShapeKind::Chart(Box::new(c)),
+        ..Default::default()
+    };
+    let img = render(vec![shape(2, bars), shape(3, scatter)]);
+    assert!(img.width > 0);
 }

crates/render/src/text_draw.rs

@@ -35,22 +35,30 @@ pub(crate) fn prompt_body(rctx: &Ctx, s: &Shape, kind: PhType) -> TextBody {
     t
 }
 
+/// Most path elements this thread's glyph cache retains. Its entries are shared with the font
+/// cache, but they stay alive here after that cache evicts them, so they are bounded by elements.
+const GLYPH_CACHE_MAX_ELEMENTS: usize = 1 << 22;
+
 thread_local! {
-    static GLYPH_CACHE: std::cell::RefCell<HashMap<(u32, u32), Arc<BezPath>>> = std::cell::RefCell::new(HashMap::new());
+    /// The cached outlines, and the path elements they hold.
+    static GLYPH_CACHE: std::cell::RefCell<(HashMap<(u32, u32), Arc<BezPath>>, usize)> = std::cell::RefCell::new((HashMap::new(), 0));
 }
 
 pub(crate) fn glyph(face: &deckcraft_fonts::FontFace, gid: u32) -> Arc<BezPath> {
     let key = (face.id(), gid);
-    if let Some(p) = GLYPH_CACHE.with(|c| c.borrow().get(&key).cloned()) {
+    if let Some(p) = GLYPH_CACHE.with(|c| c.borrow().0.get(&key).cloned()) {
         return p;
     }
     let p = FontDb::global().outline(face, gid);
     GLYPH_CACHE.with(|c| {
         let mut c = c.borrow_mut();
-        if c.len() > 200_000 {
-            c.clear();
+        let n = p.elements().len();
+        if c.0.len() > 200_000 || c.1.saturating_add(n) > GLYPH_CACHE_MAX_ELEMENTS {
+            c.0.clear();
+            c.1 = 0;
         }
-        c.insert(key, p.clone());
+        c.1 += n;
+        c.0.insert(key, p.clone());
     });
     p
 }
@@ -105,6 +113,7 @@ pub fn draw_layout(ctx: &mut RenderContext, l: &deckcraft_text::TextLayout, tr:
 pub fn draw_layout_with(ctx: &mut RenderContext, l: &deckcraft_text::TextLayout, tr: Rect, m: Affine, paras: &[(usize, ParaState)]) {
     let para = |i: usize| paras.iter().find(|(p, _)| *p == i).map(|(_, s)| *s).unwrap_or_default();
     let m = text_transform(m, tr, l.rotation);
+    let lines_of = LineIndex::new(l);
     let deco = |ctx: &mut RenderContext, d: &deckcraft_text::Deco| {
         let ps = para(d.para);
         if !ps.visible || ps.opacity <= 0.001 {
@@ -144,7 +153,7 @@ pub fn draw_layout_with(ctx: &mut RenderContext, l: &deckcraft_text::TextLayout,
                 draw_glyph(ctx, run, *gid, at, ps.opacity);
                 continue;
             };
-            let li = line_at(l, run.para, *y);
+            let li = lines_of.line_at(run.para, *y);
             if !grads.iter().any(|(i, _)| *i == li) {
                 let scheme = deckcraft_color::ColorScheme { name: String::new(), colors: [Rgba::BLACK; 12] };
                 let stops = g.stops.iter().map(|s| (s.pos, s.color.resolve(&scheme, None))).collect();
@@ -191,8 +200,78 @@ pub(crate) fn fill_deco(ctx: &mut RenderContext, d: &deckcraft_text::Deco) {
     }
 }
 
-/// The line of paragraph `para` holding a glyph on baseline `y` (the nearest baseline).
-fn line_at(l: &deckcraft_text::TextLayout, para: usize, y: f64) -> usize {
+/// Finds the line of a paragraph holding a glyph on baseline `y` without scanning the paragraph's
+/// lines for every glyph. A paragraph whose lines are ordered top to bottom (every layout the text
+/// crate produces) is searched by bisection; any other falls back to a scan with the same answer.
+pub(crate) struct LineIndex<'a> {
+    l: &'a deckcraft_text::TextLayout,
+    /// Per paragraph: its lines' tops, bottoms and baselines all rise with the line index.
+    ordered: Vec<bool>,
+}
+
+impl<'a> LineIndex<'a> {
+    pub(crate) fn new(l: &'a deckcraft_text::TextLayout) -> Self {
+        let ordered = l
+            .para_lines
+            .iter()
+            .map(|&(first, count)| {
+                let end = first.saturating_add(count).min(l.lines.len());
+                l.lines.get(first..end).is_some_and(|ls| {
+                    ls.iter().all(|a| a.top <= a.bottom)
+                        && ls.windows(2).all(|w| w[0].top <= w[1].top && w[0].bottom <= w[1].bottom && w[0].baseline <= w[1].baseline)
+                })
+            })
+            .collect();
+        LineIndex { l, ordered }
+    }
+
+    /// The nearest line baseline to `y` among `lines` (the first of equals), as an index into `lines`.
+    fn nearest(lines: &[deckcraft_text::LineInfo], y: f64) -> Option<usize> {
+        let i = lines.partition_point(|li| li.baseline < y);
+        let best = match (i.checked_sub(1), lines.get(i)) {
+            (Some(p), Some(n)) => {
+                if (lines[p].baseline - y).abs() <= (n.baseline - y).abs() {
+                    p
+                } else {
+                    i
+                }
+            }
+            (Some(p), None) => p,
+            (None, Some(_)) => i,
+            (None, None) => return None,
+        };
+        let b = lines[best].baseline;
+        Some(lines.partition_point(|li| li.baseline < b))
+    }
+
+    /// The paragraph's lines when they are ordered, with the index of the first.
+    fn ordered_lines(&self, para: usize) -> Option<(usize, &[deckcraft_text::LineInfo])> {
+        let &(first, count) = self.l.para_lines.get(para)?;
+        let end = first.saturating_add(count).min(self.l.lines.len());
+        (self.ordered[para] && first < end).then(|| (first, &self.l.lines[first..end]))
+    }
+
+    /// The line of paragraph `para` holding a glyph on baseline `y` (the nearest baseline).
+    pub(crate) fn line_at(&self, para: usize, y: f64) -> usize {
+        if let Some((first, ls)) = self.ordered_lines(para) {
+            return Self::nearest(ls, y).map_or(0, |i| first + i);
+        }
+        line_at_scan(self.l, para, y)
+    }
+
+    /// The first line of paragraph `para` whose box holds `y`, else the nearest baseline's line.
+    pub(crate) fn line_of(&self, para: usize, y: f64) -> Option<usize> {
+        let Some((first, ls)) = self.ordered_lines(para) else { return crate::warp::line_of_scan(self.l, para, y) };
+        let i = ls.partition_point(|li| li.bottom + 0.01 < y);
+        if ls.get(i).is_some_and(|li| y >= li.top - 0.01) {
+            return Some(first + i);
+        }
+        Self::nearest(ls, y).map(|i| first + i)
+    }
+}
+
+/// The line of paragraph `para` holding a glyph on baseline `y` (the nearest baseline), by scanning.
+fn line_at_scan(l: &deckcraft_text::TextLayout, para: usize, y: f64) -> usize {
     if let Some(&(first, count)) = l.para_lines.get(para) {
         if count == 0 {
             return 0;
@@ -318,3 +397,38 @@ fn draw_glyph_with(
         ctx.stroke_path(&path);
     }
 }
+
+#[cfg(test)]
+mod line_index_tests {
+    use super::*;
+    use deckcraft_text::{LineInfo, TextLayout};
+
+    fn layout(ordered: bool) -> TextLayout {
+        let line = |para, top: f64| LineInfo { para, top, baseline: top + 8.0, bottom: top + 10.0, ..Default::default() };
+        let mut lines: Vec<LineInfo> = (0..40).map(|i| line(usize::from(i >= 25), f64::from(i) * 10.0)).collect();
+        if !ordered {
+            lines.swap(3, 7);
+        }
+        TextLayout { lines, para_lines: vec![(0, 25), (25, 15)], ..Default::default() }
+    }
+
+    #[test]
+    fn bisection_matches_the_scan() {
+        for ordered in [true, false] {
+            let l = layout(ordered);
+            let idx = LineIndex::new(l_ref(&l));
+            assert_eq!(idx.ordered, vec![ordered, true]);
+            for para in 0..2 {
+                for k in -20..450 {
+                    let y = f64::from(k) * 0.9;
+                    assert_eq!(idx.line_at(para, y), line_at_scan(&l, para, y), "line_at {para} {y}");
+                    assert_eq!(idx.line_of(para, y), crate::warp::line_of_scan(&l, para, y), "line_of {para} {y}");
+                }
+            }
+        }
+    }
+
+    fn l_ref(l: &TextLayout) -> &TextLayout {
+        l
+    }
+}

crates/render/src/warp.rs

@@ -9,13 +9,14 @@ use deckcraft_text::{GlyphRun, TextLayout};
 use kurbo::{Affine, BezPath, PathEl, Point, Rect, Shape as _};
 use vello_cpu::{RenderContext, peniko};
 
+use crate::text_draw::LineIndex;
 use crate::{ParaState, color, glyph, scale_of, text_transform};
 
 /// Most points one warped glyph may have (a hostile size or zoom can't explode the work).
 const MAX_POINTS: usize = 40_000;
 
-/// The line of `l` a glyph of paragraph `para` on baseline `y` belongs to.
-fn line_of(l: &TextLayout, para: usize, y: f64) -> Option<usize> {
+/// The line of `l` a glyph of paragraph `para` on baseline `y` belongs to, by scanning.
+pub(crate) fn line_of_scan(l: &TextLayout, para: usize, y: f64) -> Option<usize> {
     if let Some(&(first, count)) = l.para_lines.get(para) {
         if count == 0 {
             return None;
@@ -110,6 +111,7 @@ pub(crate) fn draw(ctx: &mut RenderContext, l: &TextLayout, tr: Rect, m: Affine,
     let para = |i: usize| paras.iter().find(|(p, _)| *p == i).map(|(_, s)| *s).unwrap_or_default();
     let m = text_transform(m, tr, l.rotation);
     let n = l.lines.len();
+    let lines_of = LineIndex::new(l);
     let mut ink: Vec<Option<Rect>> = vec![None; n];
     let mut off: Vec<Option<f64>> = vec![None; n];
     let mut items: Vec<Item> = Vec::new();
@@ -117,7 +119,7 @@ pub(crate) fn draw(ctx: &mut RenderContext, l: &TextLayout, tr: Rect, m: Affine,
         let k = run.size / run.face.upem.max(1.0);
         let skew = if run.fake_italic { Affine::new([1.0, 0.0, -0.2, 1.0, 0.0, 0.0]) } else { Affine::IDENTITY };
         for (gid, x, y) in &run.glyphs {
-            let Some(li) = line_of(l, run.para, *y) else { continue };
+            let Some(li) = lines_of.line_of(run.para, *y) else { continue };
             if let Some(o) = off.get_mut(li) {
                 *o = Some(o.map_or(ref_offset(run), |v| v.max(ref_offset(run))));
             }
@@ -156,7 +158,7 @@ pub(crate) fn draw(ctx: &mut RenderContext, l: &TextLayout, tr: Rect, m: Affine,
             return;
         }
         let y = (d.rect.y0 + d.rect.y1) / 2.0;
-        let Some(li) = line_of(l, d.para, y) else { return };
+        let Some(li) = lines_of.line_of(d.para, y) else { return };
         ctx.set_transform(m * Affine::translate(ps.offset));
         ctx.set_paint(color(d.color, ps.opacity));
         for r in d.pieces() {

crates/text/src/breaking.rs

@@ -260,12 +260,15 @@ pub(crate) struct Tab {
     align: TabAlign,
 }
 
+/// The paragraph's tab stops in position order (a stop at no finite position is left out), so
+/// [`tab_advance`] finds the next one by binary search instead of a scan per tab.
 pub(crate) fn tabs_of(props: &ParaProps) -> Vec<Tab> {
-    props
+    let mut tabs: Vec<Tab> = props
         .tabs
         .as_ref()
         .map(|t| {
             t.iter()
+                .filter(|s| s.pos.is_finite())
                 .map(|s| Tab {
                     pos: s.pos,
                     align: match s.align.as_str() {
@@ -277,7 +280,9 @@ pub(crate) fn tabs_of(props: &ParaProps) -> Vec<Tab> {
                 })
                 .collect()
         })
-        .unwrap_or_default()
+        .unwrap_or_default();
+    tabs.sort_by(|a, b| a.pos.total_cmp(&b.pos));
+    tabs
 }
 
 /// Width of the text after the tab at cell `i` up to the next tab or line break, and the width of
@@ -301,18 +306,30 @@ pub(crate) fn tab_segment(cells: &[Cell], i: usize) -> (f64, f64) {
 /// (`seg`: its width, and its width before the decimal point) as the stop aligns it but never
 /// moving back, as PowerPoint does; past the last stop, to the next default stop.
 pub(crate) fn tab_advance(x: f64, stops: &[Tab], default_tab: f64, seg: (f64, f64)) -> f64 {
-    for s in stops {
-        if s.pos > x + 0.5 {
-            let to = s.pos - x;
-            return match s.align {
-                TabAlign::Left => to,
-                TabAlign::Right => (to - seg.0).max(0.0),
-                TabAlign::Center => (to - seg.0 / 2.0).max(0.0),
-                TabAlign::Decimal => (to - seg.1).max(0.0),
-            };
-        }
+    // `stops` is in position order (`tabs_of`): the next stop is the first past x.
+    // A NaN `x` (a NaN spacing upstream) skips the lookup and takes the finite default-stop path.
+    if let Some(s) = stops.get(stops.partition_point(|s| s.pos <= x + 0.5)).filter(|_| !x.is_nan()) {
+        let to = s.pos - x;
+        return match s.align {
+            TabAlign::Left => to,
+            TabAlign::Right => (to - seg.0).max(0.0),
+            TabAlign::Center => (to - seg.0 / 2.0).max(0.0),
+            TabAlign::Decimal => (to - seg.1).max(0.0),
+        };
     }
     let d = if default_tab > 1.0 { default_tab } else { 72.0 };
     let next = ((x / d).floor() + 1.0) * d;
     (next - x).max(1.0)
 }
+
+#[cfg(test)]
+mod tab_tests {
+    use super::*;
+
+    #[test]
+    fn a_nan_position_takes_the_finite_default_stop() {
+        let stops = [Tab { pos: 100.0, align: TabAlign::Left }];
+        assert!(tab_advance(f64::NAN, &stops, 72.0, (0.0, 0.0)).is_finite());
+        assert_eq!(tab_advance(10.0, &stops, 72.0, (0.0, 0.0)), 90.0);
+    }
+}

crates/text/src/run.rs

@@ -22,7 +22,7 @@ pub struct GlyphRun {
     pub link: bool,
     /// Opacity of the fill on top of `color`'s own alpha (0 for no fill).
     pub alpha: f64,
-    pub gradient: Option<deckcraft_model::style::Gradient>,
+    pub gradient: Option<std::sync::Arc<deckcraft_model::style::Gradient>>,
     /// Shadow and glow behind the glyphs (`a:rPr/a:effectLst`).
     pub effects: Option<RunEffects>,
     /// East Asian vertical text (`eaVert`): each glyph stands upright, turned a quarter turn

crates/text/src/style.rs

@@ -46,7 +46,7 @@ pub(crate) struct Style {
     pub(crate) highlight: Option<Rgba>,
     pub(crate) outline: Option<(Rgba, f64)>,
     pub(crate) link: bool,
-    pub(crate) gradient: Option<deckcraft_model::style::Gradient>,
+    pub(crate) gradient: Option<std::sync::Arc<deckcraft_model::style::Gradient>>,
     pub(crate) effects: Option<RunEffects>,
     /// "Regular", "Bold"… for the slot and fallback faces.
     pub(crate) style_name: &'static str,
@@ -136,7 +136,7 @@ pub(crate) fn make_style(ctx: &Ctx, r: &RunProps, scale: f64, prompt: Option<Rgb
             for s in &mut g.stops {
                 s.color = deckcraft_model::ColorRef::rgb(ctx.color(&s.color, None));
             }
-            (g.stops.first().map(|s| ctx.color(&s.color, None)).unwrap_or(Rgba::BLACK), 1.0, Some(g))
+            (g.stops.first().map(|s| ctx.color(&s.color, None)).unwrap_or(Rgba::BLACK), 1.0, Some(std::sync::Arc::new(g)))
         }
         Some(Fill::None) => (Rgba::TRANSPARENT, 0.0, None),
         _ => (resolve::text_color(ctx, r), 1.0, None),

crates/text/src/tests.rs

@@ -1416,6 +1416,16 @@ fn tab_stops_align_the_text_after_them() {
     assert!((l.lines[0].edges[4].0 - x0(&l) - 72.0).abs() < 0.01);
 }
 
+#[test]
+fn many_tabs_over_many_stops_lay_out_by_position() {
+    // 20,000 stops given out of order, and 2,000 tabs: each tab finds the next stop by position.
+    let mut stops: Vec<(f64, &str)> = (1..=20_000).rev().map(|k| (k as f64 * 0.05 + 30.0, "l")).collect();
+    stops.push((f64::NAN, "l"));
+    let text = "a\t".repeat(2_000);
+    let l = tabbed(&text, &stops, 1.0e6);
+    assert!((l.lines[0].edges[2].0 - l.inner.x0 - 30.05).abs() < 0.01, "{:?}", &l.lines[0].edges[..3]);
+}
+
 #[test]
 fn a_tab_past_the_end_moves_to_the_next_line() {
     // PowerPoint: "abcdefghij\tk\tl\tm…" in a narrow box puts the tab that doesn't fit on the next

crates/ui-egui/Cargo.toml

@@ -19,6 +19,7 @@ deckcraft-anim = { workspace = true }
 deckcraft-engine = { workspace = true }
 deckcraft-media = { workspace = true }
 egui = { workspace = true, features = ["default_fonts", "monochrome_emoji_fonts"] }
+egui_extras = { workspace = true }
 craft-ui = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }

crates/ui-egui/src/app.rs

@@ -106,6 +106,7 @@ impl SlideApp {
             twisting: false,
             next_file_id: 1,
             pending_files: Vec::new(),
+            host_start: None,
             ime_tracker: egui::ime_context::ImeContextTracker::new(),
             ime_pending: None,
             ime_frame_viewport: None,

crates/ui-egui/src/app/commands.rs

@@ -20,6 +20,11 @@ impl SlideApp {
     pub fn run(&mut self, id: &str, params: Value) -> Result<Value, String> {
         let r = if UI_COMMANDS.iter().any(|c| c.0 == id) {
             self.run_ui(id, &params)
+        } else if id == "file.save" && self.services.host_save.is_some() && params.get("path").is_none() {
+            // A page that keeps the files (`?host=parent`): Save by id (the command palette) goes
+            // to the page like Ctrl+S. The engine would write to the presentation's path, which a
+            // browser can't.
+            self.save_to_host(None).map(|name| json!({"path": name}))
         } else {
             self.session.execute(id, &params).map_err(|e| e.to_string())
         };

crates/ui-egui/src/app/files.rs

@@ -462,6 +462,8 @@ impl SlideApp {
                     Err(e) => self.set_status(e.to_string()),
                 }
             }
+        } else if self.services.host_save.is_some() {
+            let _ = self.save_to_host(Some(ext));
         } else if let Some(dl) = self.services.download.as_mut()
             && let Some(d) = self.session.active()
         {
@@ -487,6 +489,10 @@ impl SlideApp {
     }
 
     pub fn save(&mut self) {
+        if self.services.host_save.is_some() {
+            let _ = self.save_to_host(None);
+            return;
+        }
         if self.session.active().and_then(|d| d.path.clone()).is_some() {
             match self.session.execute("file.save", &json!({})) {
                 Ok(_) => self.set_status("Saved"),
@@ -497,6 +503,85 @@ impl SlideApp {
         }
     }
 
+    /// Saves to the page that keeps the files ([`Services::host_save`](crate::Services::host_save)).
+    /// Save (`ext` `None`) writes the presentation's own file (the one the page sent, or the
+    /// last one saved there) in that file's format, as the desktop app does; a presentation with
+    /// no file of its own is a new `.deckcraft` file, the name Save suggests on the desktop. Save
+    /// As (`pptx`, `deckcraft`) is a new file named after the presentation. Once the page has the
+    /// bytes, the presentation is saved and that name is its file. Returns the name, or why it
+    /// wasn't saved (also shown in the status bar).
+    pub(super) fn save_to_host(&mut self, ext: Option<&str>) -> Result<String, String> {
+        use deckcraft_engine::cmd::file::{format_for_path, mark_saved, save_bytes};
+        let Some(d) = self.session.active() else { return Err("no presentation is open".into()) };
+        let own = d.path.as_deref().and_then(|p| std::path::Path::new(p).file_name()).map(|n| n.to_string_lossy().to_string());
+        let (name, save_as) = match (ext, own) {
+            (None, Some(own)) => (own, false),
+            (ext, _) => (format!("{}.{}", d.title(), ext.unwrap_or("deckcraft")), true),
+        };
+        let saved = save_bytes(&d.doc, format_for_path(&name)).map_err(|e| e.to_string()).and_then(|bytes| {
+            let host = self.services.host_save.as_mut().ok_or("no page to save to")?;
+            host(&name, &bytes, save_as).map_err(|e| format!("Couldn't save {name}: {e}"))?;
+            mark_saved(&mut self.session, Some(name.clone())).map_err(|e| e.to_string())
+        });
+        match saved {
+            Ok(()) => {
+                self.set_status(format!("Saved {name}"));
+                Ok(name)
+            }
+            Err(e) => {
+                self.set_status(e.clone());
+                Err(e)
+            }
+        }
+    }
+
+    /// A file the page that keeps the files sent (`?host=parent`), with the name it sent, if any.
+    /// It opens as File › Open opens it on the desktop: a presentation as itself, an outline
+    /// (.txt, .md, .rtf) as a new untitled presentation. The name is the presentation's file only
+    /// when the page sent one with a presentation extension and the file is an intact
+    /// presentation, so Save hands it back under that name and format; anything else (no name, an
+    /// outline, a damaged file opened as a repaired copy) is untitled, and its first Save is a new
+    /// file. The first presentation that opens takes the place of the empty one host mode started
+    /// with ([`Self::start_for_host`]), if that one is still open, untitled and unchanged; later
+    /// files open beside the others.
+    pub fn open_from_host(&mut self, name: Option<&str>, bytes: &[u8]) {
+        let blank = self.host_start.filter(|&uid| self.session.documents().iter().any(|d| d.uid == uid && d.path.is_none() && !d.is_dirty()));
+        let before = self.session.documents().len();
+        let shown = name.unwrap_or("Presentation");
+        let named = name.is_some_and(|n| is_presentation_name(&n.to_ascii_lowercase()));
+        let opened = deckcraft_engine::cmd::file::loaded_file(shown, bytes).and_then(|mut f| {
+            // `file.adopt` keeps the path only for a native file; a name the page didn't send
+            // for a presentation must not become one.
+            f.native &= named;
+            let token = self.session.stage_loaded(f);
+            self.session.execute("file.adopt", &json!({"path": shown, "token": token}))
+        });
+        if let Err(e) = opened {
+            self.notify(e.to_string());
+        }
+        self.drain_requests();
+        if self.session.documents().len() <= before {
+            return;
+        }
+        self.host_start = None;
+        if let Some(opened) = self.session.active().map(|d| d.uid)
+            && let Some(i) = self.session.documents().iter().position(|d| Some(d.uid) == blank)
+        {
+            self.session.close_document(i);
+            if let Some(i) = self.session.documents().iter().position(|d| d.uid == opened) {
+                self.session.set_active(i);
+            }
+        }
+    }
+
+    /// Host mode (`?host=parent`) starts with an empty presentation instead of the sample, for
+    /// the first file the page sends to take its place ([`Self::open_from_host`]).
+    pub fn start_for_host(&mut self) -> Result<(), String> {
+        self.run("file.new", json!({}))?;
+        self.host_start = self.session.active().map(|d| d.uid);
+        Ok(())
+    }
+
     /// Act on requests commands left for the UI.
     pub(super) fn drain_requests(&mut self) {
         for r in std::mem::take(&mut self.session.ui_requests) {

crates/ui-egui/src/app/playback.rs

@@ -144,6 +144,10 @@ impl SlideApp {
         let visible = show::viewport_visible(ctx);
         let Some(doc) = self.session.active().map(|d| d.doc.clone()) else { return };
         let Some(show) = self.show.as_mut() else { return };
+        if show.presenter_grid && self.services.presenter.as_ref().is_some_and(|host| !host.is_open()) {
+            // A web popup closed with its grid open must not hold auto-advance while this tab is hidden (#1866).
+            show.presenter_grid = false;
+        }
         if visible {
             // A visible logic-only pass (`run_logic`) carries the last full frame's input time.
             // Anchoring that stale time to `now` would move the hidden clock backwards if the

crates/ui-egui/src/backstage.rs

@@ -249,7 +249,8 @@ fn act(app: &mut SlideApp, nav: Nav, current: Page) -> Option<Page> {
     match nav {
         Nav::Page(p) => Some(p),
         Nav::Save => {
-            let web = app.services.pick_save.is_none() && app.services.download.is_some();
+            // A page that keeps the files (`host_save`) saves as the desktop does.
+            let web = app.services.pick_save.is_none() && app.services.download.is_some() && app.services.host_save.is_none();
             let has_path = app.session.active().is_some_and(|d| d.path.is_some());
             if !has_path && !web {
                 // A presentation that was never saved goes to Save As first, as in PowerPoint.

crates/ui-egui/src/backstage/info.rs

@@ -166,15 +166,28 @@ pub(super) fn save_as(app: &mut SlideApp, ui: &mut Ui, bs: &mut Backstage, out:
             })
             .response
             .widget_info(|| egui::WidgetInfo::labeled(egui::Role::ComboBox, true, "Save as type"));
-        let web = app.services.pick_save.is_none();
+        // A page that keeps the files (`host_save`) saves; plain web downloads.
+        let web = app.services.pick_save.is_none() && app.services.host_save.is_none();
         let label = if web { "Download" } else { "Save" };
         let save = ui.add(egui::Button::new(RichText::new(label).color(t.accent_text)).fill(t.accent).min_size(vec2(84.0, 26.0)));
-        if save.on_hover_text(if web { "Download the file" } else { "Choose where to save" }).clicked() {
+        if save
+            .on_hover_text(if web {
+                "Download the file"
+            } else if app.services.host_save.is_some() {
+                "Save to the page"
+            } else {
+                "Choose where to save"
+            })
+            .clicked()
+        {
             let fmt = bs.file_type;
             let done = if matches!(fmt, "pptx" | "deckcraft") {
-                let before = app.session.active().map(|d| (d.path.clone(), d.is_dirty()));
+                // A save bumps the revision, also one under the same name that leaves the path
+                // and the dirty flag as they were; a cancelled dialog or a failed save doesn't.
+                let snapshot = |app: &SlideApp| app.session.active().map(|d| (d.path.clone(), d.is_dirty(), d.revision));
+                let before = snapshot(app);
                 app.save_as_dialog(fmt);
-                web || app.session.active().map(|d| (d.path.clone(), d.is_dirty())) != before
+                web || snapshot(app) != before
             } else {
                 app.export_as(fmt, json!({}))
             };

crates/ui-egui/src/backstage/print.rs

@@ -207,7 +207,8 @@ fn preview(app: &mut SlideApp, ui: &mut Ui, bs: &mut Backstage, doc: &deckcraft_
     let mut budget = 4u32;
     let mut draw_slide = |ui: &mut Ui, i: usize, r: Rect| {
         let px = (r.width() * ui.ctx().pixels_per_point()).round().clamp(16.0, 1600.0) as u32;
-        match app.textures.thumb(ui.ctx(), doc, i, px, &mut budget) {
+        // Print preview matches the actual exported PDF output (always full color).
+        match app.textures.thumb(ui.ctx(), doc, i, px, false, &mut budget) {
             Some(tex) => {
                 ui.painter().image(tex.id(), r, Rect::from_min_max(pos2(0.0, 0.0), pos2(1.0, 1.0)), Color32::WHITE);
             }

crates/ui-egui/src/backstage/tests.rs

@@ -393,6 +393,64 @@ fn ctrl_w_asks_before_closing_unsaved_changes() {
     assert_eq!(h.state().dialog.as_ref().map(|d| d.id.as_str()), Some("close"));
 }
 
+/// Framed by a page that keeps the files (`?host=parent`), the Close prompt's Save is a real save:
+/// when the page doesn't get the file the presentation stays open with its changes, and when it
+/// does the presentation closes. (A plain browser download closes either way.)
+#[test]
+fn host_close_prompt_keeps_the_presentation_when_the_save_fails() {
+    for fail in [true, false] {
+        let services = Services {
+            host_save: Some(Box::new(move |_: &str, _: &[u8], _: bool| if fail { Err("the page is gone".into()) } else { Ok(()) })),
+            download: Some(Box::new(|_: &str, _: &[u8]| {})),
+            ..Default::default()
+        };
+        let mut h = harness(SlideApp::new(Session::with_new(), services));
+        h.state_mut().run("slide.new", json!({})).unwrap();
+        h.run_steps(2);
+        h.key_press_modifiers(Modifiers::COMMAND, Key::W);
+        h.run_steps(3);
+        assert_eq!(h.state().dialog.as_ref().map(|d| d.id.as_str()), Some("close"));
+        // Enter is the prompt's Save.
+        h.key_press(Key::Enter);
+        h.run_steps(3);
+        assert!(h.state().dialog.is_none(), "fail={fail}");
+        let open = h.state().session.documents().len();
+        assert_eq!(open, usize::from(fail), "fail={fail}: open presentations");
+        if fail {
+            assert!(h.state().session.active().unwrap().is_dirty());
+        }
+    }
+}
+
+/// Framed by a page that keeps the files, Save As › Save under the presentation's own name goes
+/// back to the slide once the page has the file. The bug this prevents: that save leaves the
+/// file and the dirty flag as they were, so the Save As page stayed open and a second click sent
+/// the file again.
+#[test]
+fn host_save_as_under_the_same_name_returns_to_the_slide() {
+    let got: Rc<RefCell<Vec<(String, bool)>>> = Default::default();
+    let saves = got.clone();
+    let services = Services {
+        host_save: Some(Box::new(move |name: &str, _: &[u8], save_as: bool| {
+            saves.borrow_mut().push((name.to_string(), save_as));
+            Ok(())
+        })),
+        download: Some(Box::new(|_: &str, _: &[u8]| {})),
+        ..Default::default()
+    };
+    let mut app = SlideApp::new(Session::new(), services);
+    app.start_for_host().unwrap();
+    let deck = deckcraft_engine::cmd::file::save_bytes(&Session::with_new().doc().unwrap().doc, "pptx").unwrap();
+    app.open_from_host(Some("deck.pptx"), &deck);
+    let mut h = harness(app);
+    h.state_mut().run("app.backstage", json!({"page": "saveAs"})).unwrap();
+    h.run_steps(3);
+    click_on_page(&h, "Save");
+    h.run_steps(3);
+    assert_eq!(*got.borrow(), [("deck.pptx".to_string(), true)]);
+    assert!(h.state().backstage.is_none(), "the save returns to the slide");
+}
+
 /// Info shows the presentation's counts and properties, and edits them through file.properties.
 #[test]
 fn info_shows_and_edits_the_properties() {

crates/ui-egui/src/canvas.rs

@@ -299,7 +299,7 @@ pub fn show(app: &mut SlideApp, ui: &mut Ui) {
             vec2(w as f32 * scale, h as f32 * scale),
         );
         let mut budget = 2;
-        if let Some(tex) = app.textures.thumb(ui.ctx(), &doc, idx, (r.width() * ppp).round().max(1.0) as u32, &mut budget) {
+        if let Some(tex) = app.textures.thumb(ui.ctx(), &doc, idx, (r.width() * ppp).round().max(1.0) as u32, app.ui.grayscale, &mut budget) {
             painter.image(tex.id(), r, Rect::from_min_max(pos2(0.0, 0.0), pos2(1.0, 1.0)), Color32::WHITE);
         }
     }

crates/ui-egui/src/dialogs/about.rs

@@ -1,7 +1,7 @@
 use super::{Color32, CornerRadius, Rect, Sense, SlideApp, Stroke, Tokens, Ui, pos2, theme, vec2};
 
 /// Room the About credits need for their table; the About tab keeps its compact size.
-pub(super) const CREDITS_SIZE: egui::Vec2 = vec2(640.0, 380.0);
+pub(super) const CREDITS_SIZE: egui::Vec2 = vec2(820.0, 380.0);
 
 /// The Contributors / Models body in a block of its own fixed size, below the tab row. Sizing the
 /// dialog's `ui` instead (`set_min_size` / `set_max_height`) squeezed the tab row and the first

crates/ui-egui/src/dialogs/body.rs

@@ -339,8 +339,9 @@ fn dlg_close(app: &mut SlideApp, ui: &mut Ui, _d: &mut Dialog) -> bool {
             let save = ui.add(egui::Button::new(egui::RichText::new("Save").color(t.accent_text)).fill(t.accent).min_size(vec2(72.0, 24.0)));
             if save.clicked() || ui.input(|i| i.key_pressed(egui::Key::Enter)) {
                 app.save();
-                // In the browser a save is a download: the presentation stays "unsaved".
-                let web = app.services.pick_save.is_none() && app.services.download.is_some();
+                // In the browser a save is a download: the presentation stays "unsaved". A page
+                // that keeps the files saves it for real, so a failed save keeps it open.
+                let web = app.services.pick_save.is_none() && app.services.download.is_some() && app.services.host_save.is_none();
                 if web || app.session.active().is_some_and(|d| !d.is_dirty()) {
                     run(app, "file.close", json!({}));
                 }

crates/ui-egui/src/dialogs/credits.rs

@@ -246,12 +246,14 @@ pub fn contributors_ui(ui: &mut egui::Ui) {
     let list = sorted(CONTRIBUTORS, v.names, v.key, v.ascending);
     ui.label(RichText::new(format!("{} contributors · {} commits", list.len(), group(TOTAL_COMMITS))).small().weak());
     ui.separator();
-    egui::ScrollArea::both().auto_shrink([false, false]).show(ui, |ui| {
-        if list.is_empty() {
-            ui.label("No contributor data was built into this copy.");
-        } else if v.table {
-            table(ui, &list, &mut v);
-        } else {
+    if list.is_empty() {
+        ui.label("No contributor data was built into this copy.");
+    } else if v.table {
+        // The table scrolls vertically itself, under a fixed header; it only scrolls sideways
+        // once its columns are dragged wider than the dialog.
+        egui::ScrollArea::horizontal().auto_shrink([false, false]).show(ui, |ui| table(ui, &list, &mut v));
+    } else {
+        egui::ScrollArea::vertical().auto_shrink([false, false]).show(ui, |ui| {
             ui.horizontal_wrapped(|ui| {
                 for (i, c) in list.iter().enumerate() {
                     if i > 0 {
@@ -260,39 +262,153 @@ pub fn contributors_ui(ui: &mut egui::Ui) {
                     ui.hyperlink_to(c.name(v.names), format!("https://github.com/{}", c.login)).on_hover_text(c.summary());
                 }
             });
-        }
-    });
+        });
+    }
     ui.data_mut(|d| d.insert_temp(id, v));
 }
 
-fn table(ui: &mut egui::Ui, list: &[&Contributor], v: &mut View) {
-    egui::Grid::new("credits_table").striped(true).num_columns(SortKey::ALL.len()).show(ui, |ui| {
-        for k in SortKey::ALL {
-            let arrow = if v.key == k { if v.ascending { " ▲" } else { " ▼" } } else { "" };
-            if ui.button(RichText::new(format!("{}{arrow}", k.label().1)).strong()).on_hover_text(k.label().0).clicked() {
-                if v.key == k {
-                    v.ascending = !v.ascending;
-                } else {
-                    v.key = k;
-                    v.ascending = k.default_ascending();
-                }
+/// How the contributor table's spare width is shared out: all of it to Name.
+const CONTRIBUTOR_GROW: [f32; 10] = [1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0];
+
+/// How the model table's spare width is shared out: to Company and Model, the text columns.
+const MODEL_GROW: [f32; 6] = [1.0, 2.0, 0.0, 0.0, 0.0, 0.0];
+
+/// The narrowest a column can be dragged.
+const MIN_COLUMN: f32 = 28.0;
+
+/// The width a column needs for its header and its widest cell.
+fn natural(ui: &egui::Ui, header: RichText, cells: impl Iterator<Item = String>) -> f32 {
+    let measure = |text: egui::WidgetText| text.into_galley(ui, Some(egui::TextWrapMode::Extend), f32::INFINITY, egui::TextStyle::Body).size().x;
+    let widest = cells.map(|c| measure(c.into())).fold(measure(header.into()), f32::max);
+    widest + 2.0 * ui.spacing().button_padding.x
+}
+
+/// Opening column widths: each column's natural width, with the spare room shared out by `grow`,
+/// so the columns fill `room` exactly. When there is too little room, only the growing columns
+/// give way, each in proportion to its width above [`MIN_COLUMN`], and none goes below that.
+fn fit_widths(natural: &[f32], grow: &[f32], room: f32) -> Vec<f32> {
+    let spare = room - natural.iter().sum::<f32>();
+    let weight = grow.iter().sum::<f32>();
+    let slack = |w: f32| (w - MIN_COLUMN).max(0.0);
+    let flexible: f32 = natural.iter().zip(grow).filter(|(_, g)| **g > 0.0).map(|(w, _)| slack(*w)).sum();
+    natural
+        .iter()
+        .zip(grow)
+        .map(|(w, g)| {
+            if *g > 0.0 && spare >= 0.0 {
+                w + spare * g / weight
+            } else if *g > 0.0 && flexible > 0.0 {
+                w - (-spare).min(flexible) * slack(*w) / flexible
+            } else {
+                *w
             }
-        }
-        ui.end_row();
-        for c in list {
-            ui.hyperlink_to(c.name(v.names), format!("https://github.com/{}", c.login)).on_hover_text(c.summary());
-            ui.label(group(c.prs));
-            ui.label(group(c.commits));
-            ui.label(group(c.lines_added));
-            ui.label(group(c.lines_deleted));
-            ui.label(signed(c.lines_delta()));
-            ui.label(group(c.binary_added));
-            ui.label(group(c.binary_deleted));
-            ui.label(day(c.first_commit));
-            ui.label(day(c.last_commit));
-            ui.end_row();
-        }
-    });
+        })
+        .collect()
+}
+
+/// A striped table whose columns open at [`fit_widths`], so it fills the width and nothing scrolls
+/// sideways. Every column, the last included, can be dragged wider or narrower at its right edge:
+/// only a table dragged wider than the window scrolls sideways. Text too long for its column is
+/// clipped. When a column's natural width or the window changes, the columns go back to a new fit,
+/// dropping any dragged widths.
+fn fitted_table<'a>(ui: &'a mut egui::Ui, id: &str, natural: &[f32], grow: &[f32]) -> egui_extras::TableBuilder<'a> {
+    // Every cell is followed by the item gap, and the vertical scrollbar keeps its margins.
+    let s = ui.spacing();
+    let gaps = s.item_spacing.x * natural.len() as f32;
+    let bar = s.scroll.bar_width + s.scroll.bar_inner_margin + s.scroll.bar_outer_margin;
+    let widths = fit_widths(natural, grow, (ui.available_width() - gaps - bar).max(0.0));
+    // The table keeps its own column widths, so a change in what they were fitted to has to clear
+    // them. A longer name can leave the fit itself unchanged, and scrolling can nudge the available
+    // width, so this compares the natural widths and the clip rect, which scrolling never moves.
+    let fit = egui::Id::unique(("credits_fit", id));
+    let measured = (natural.to_vec(), ui.clip_rect().width());
+    let refit = ui.data_mut(|d| d.get_temp::<(Vec<f32>, f32)>(fit)).as_ref() != Some(&measured);
+    ui.data_mut(|d| d.insert_temp(fit, measured));
+    let mut t =
+        egui_extras::TableBuilder::new(ui).id_salt(id).striped(true).resizable(true).auto_shrink([false, false]).max_scroll_height(f32::INFINITY);
+    if refit {
+        t.reset();
+    }
+    for w in widths {
+        t = t.column(egui_extras::Column::initial(w).at_least(MIN_COLUMN).clip(true));
+    }
+    t
+}
+
+/// Add a cell's widget right-aligned (counts, dates) or left-aligned (names), vertically centred.
+fn aligned<R>(ui: &mut egui::Ui, right: bool, add: impl FnOnce(&mut egui::Ui) -> R) -> R {
+    let layout = if right { egui::Layout::right_to_left(egui::Align::Center) } else { egui::Layout::left_to_right(egui::Align::Center) };
+    ui.with_layout(layout, add).inner
+}
+
+fn row_height(ui: &egui::Ui) -> f32 {
+    ui.text_style_height(&egui::TextStyle::Body) + 6.0
+}
+
+/// One contributor's table cells after the name, in `SortKey::ALL` order.
+fn cells(c: &Contributor) -> [String; 9] {
+    [
+        group(c.prs),
+        group(c.commits),
+        group(c.lines_added),
+        group(c.lines_deleted),
+        signed(c.lines_delta()),
+        group(c.binary_added),
+        group(c.binary_deleted),
+        day(c.first_commit).to_string(),
+        day(c.last_commit).to_string(),
+    ]
+}
+
+/// A contributor-table header. The sorted column is highlighted; its direction shows on the
+/// toolbar's sort-order button, so no arrow widens the column.
+fn header_text(k: SortKey) -> RichText {
+    RichText::new(k.label().1).strong()
+}
+
+fn table(ui: &mut egui::Ui, list: &[&Contributor], v: &mut View) {
+    let h = row_height(ui);
+    let rows: Vec<[String; 9]> = list.iter().map(|c| cells(c)).collect();
+    let widths: Vec<f32> = SortKey::ALL
+        .iter()
+        .enumerate()
+        .map(|(i, &k)| match i.checked_sub(1) {
+            None => natural(ui, header_text(k), list.iter().map(|c| c.name(v.names))),
+            Some(col) => natural(ui, header_text(k), rows.iter().filter_map(|r| r.get(col).cloned())),
+        })
+        .collect();
+    fitted_table(ui, "credits_table", &widths, &CONTRIBUTOR_GROW)
+        .header(h + 4.0, |mut header| {
+            for k in SortKey::ALL {
+                header.col(|ui| {
+                    let r = aligned(ui, k != SortKey::Name, |ui| ui.selectable_label(v.key == k, header_text(k))).on_hover_text(k.label().0);
+
+                    if r.clicked() {
+                        if v.key == k {
+                            v.ascending = !v.ascending;
+                        } else {
+                            v.key = k;
+                            v.ascending = k.default_ascending();
+                        }
+                    }
+                });
+            }
+        })
+        .body(|mut body| {
+            for (c, cells) in list.iter().zip(rows) {
+                body.row(h, |mut row| {
+                    row.col(|ui| {
+                        aligned(ui, false, |ui| ui.hyperlink_to(c.name(v.names), format!("https://github.com/{}", c.login)))
+                            .on_hover_text(c.summary());
+                    });
+                    for text in cells {
+                        row.col(|ui| {
+                            aligned(ui, true, |ui| ui.label(text));
+                        });
+                    }
+                });
+            }
+        });
 }
 
 /// About ▸ Models: AI models credited in Co-Authored-By trailers.
@@ -302,22 +418,48 @@ pub fn models_ui(ui: &mut egui::Ui) {
         return;
     }
     let assisted: u64 = MODELS.iter().map(|m| m.commits).max().unwrap_or(0).max(1);
-    egui::ScrollArea::both().auto_shrink([false, false]).show(ui, |ui| {
-        egui::Grid::new("credits_models").striped(true).num_columns(6).show(ui, |ui| {
-            for h in ["Company", "Model", "Version", "Commits", "% of all commits", "Lines +/−"] {
-                ui.label(RichText::new(h).strong());
-            }
-            ui.end_row();
-            for m in MODELS {
-                ui.label(m.company);
-                ui.label(m.model);
-                ui.label(m.version);
-                ui.label(group(m.commits));
-                ui.label(format!("{:.0}%", 100.0 * m.commits as f64 / TOTAL_COMMITS.max(assisted) as f64));
-                ui.label(format!("+{} / −{}", group(m.lines_added), group(m.lines_deleted)));
-                ui.end_row();
-            }
-        });
+    let h = row_height(ui);
+    let titles = ["Company", "Model", "Version", "Commits", "% of all commits", "Lines +/−"];
+    // Company, Model and Version read as text; the counts line up on the right.
+    let right = [false, false, false, true, true, true];
+    let rows: Vec<[String; 6]> = MODELS
+        .iter()
+        .map(|m| {
+            [
+                m.company.to_string(),
+                m.model.to_string(),
+                m.version.to_string(),
+                group(m.commits),
+                format!("{:.0}%", 100.0 * m.commits as f64 / TOTAL_COMMITS.max(assisted) as f64),
+                format!("+{} / −{}", group(m.lines_added), group(m.lines_deleted)),
+            ]
+        })
+        .collect();
+    let widths: Vec<f32> = titles
+        .iter()
+        .enumerate()
+        .map(|(i, title)| natural(ui, RichText::new(*title).strong(), rows.iter().filter_map(|r| r.get(i).cloned())))
+        .collect();
+    egui::ScrollArea::horizontal().id_salt("credits_models").auto_shrink([false, false]).show(ui, |ui| {
+        fitted_table(ui, "credits_models", &widths, &MODEL_GROW)
+            .header(h + 4.0, |mut header| {
+                for (title, r) in titles.into_iter().zip(right) {
+                    header.col(|ui| {
+                        aligned(ui, r, |ui| ui.label(RichText::new(title).strong()));
+                    });
+                }
+            })
+            .body(|mut body| {
+                for cells in rows {
+                    body.row(h, |mut row| {
+                        for (text, r) in cells.into_iter().zip(right) {
+                            row.col(|ui| {
+                                aligned(ui, r, |ui| ui.label(text));
+                            });
+                        }
+                    });
+                }
+            });
     });
 }
 
@@ -397,4 +539,131 @@ mod tests {
         assert_eq!(day("2026-10-07T18:45:23Z"), "2026-10-07");
         assert_eq!(day(""), "—");
     }
+
+    #[test]
+    fn columns_fill_the_room_and_spare_width_goes_to_growing_columns() {
+        assert_eq!(fit_widths(&[100.0, 40.0, 60.0], &[1.0, 0.0, 0.0], 300.0), [200.0, 40.0, 60.0]);
+        assert_eq!(fit_widths(&[100.0, 40.0, 60.0], &[1.0, 2.0, 0.0], 230.0), [110.0, 60.0, 60.0]);
+        let w = fit_widths(&[123.0, 45.5, 67.25], &[1.0, 0.0, 2.0], 512.0);
+        assert!((w.iter().sum::<f32>() - 512.0).abs() < 0.01, "a fitted table neither scrolls nor leaves a gap: {w:?}");
+    }
+
+    #[test]
+    fn too_little_room_shrinks_only_growing_columns() {
+        assert_eq!(fit_widths(&[100.0, 40.0, 60.0], &[1.0, 0.0, 0.0], 150.0), [50.0, 40.0, 60.0]);
+        assert_eq!(fit_widths(&[100.0, 40.0, 60.0], &[1.0, 0.0, 0.0], 0.0), [MIN_COLUMN, 40.0, 60.0]);
+        assert_eq!(fit_widths(&[100.0, 40.0], &[0.0, 0.0], 50.0), [100.0, 40.0]);
+    }
+
+    #[test]
+    fn a_column_at_the_minimum_leaves_the_shortfall_to_the_others() {
+        let w = fit_widths(&[100.0, 300.0, 50.0], &[1.0, 1.0, 0.0], 140.0);
+        assert!((w.iter().sum::<f32>() - 140.0).abs() < 0.01, "the columns still fit the room: {w:?}");
+        assert!(w.iter().all(|c| *c >= MIN_COLUMN), "no column goes below the minimum: {w:?}");
+        assert_eq!(fit_widths(&[100.0, 300.0, 50.0], &[1.0, 1.0, 0.0], 0.0), [MIN_COLUMN, MIN_COLUMN, 50.0]);
+    }
+
+    const WINDOW: f32 = 640.5;
+    const NATURAL: [f32; 3] = [120.0, 80.0, 80.0];
+    const GROW: [f32; 3] = [1.0, 0.0, 0.0];
+
+    /// One frame of a table long enough to scroll; the rects of its header cells.
+    fn table_frame(ctx: &egui::Context, width: f32, natural: &[f32], events: Vec<egui::Event>) -> Vec<egui::Rect> {
+        scrolled_frame(ctx, width, natural, 0.0, events)
+    }
+
+    /// [`table_frame`], scrolled `offset` points sideways.
+    fn scrolled_frame(ctx: &egui::Context, width: f32, natural: &[f32], offset: f32, events: Vec<egui::Event>) -> Vec<egui::Rect> {
+        let screen_rect = Some(egui::Rect::from_min_size(egui::Pos2::ZERO, egui::vec2(width, 300.0)));
+        let raw = egui::RawInput { screen_rect, events, ..Default::default() };
+        let mut cells = Vec::new();
+        let out = ctx.run_ui(raw, |ui| {
+            cells.clear();
+            egui::ScrollArea::horizontal().auto_shrink([false, false]).horizontal_scroll_offset(offset).show(ui, |ui| {
+                fitted_table(ui, "test", natural, &GROW)
+                    .header(20.0, |mut header| {
+                        for _ in natural {
+                            header.col(|ui| cells.push(ui.max_rect()));
+                        }
+                    })
+                    .body(|mut body| {
+                        for _ in 0..40 {
+                            body.row(20.0, |mut row| {
+                                for _ in natural {
+                                    row.col(|ui| {
+                                        ui.label("x");
+                                    });
+                                }
+                            });
+                        }
+                    });
+            });
+        });
+        out.drop_without_applying_deltas();
+        cells
+    }
+
+    /// A new context with the table open and settled, and the rects of its header cells.
+    fn opened_table() -> (egui::Context, Vec<egui::Rect>) {
+        let ctx = egui::Context::default();
+        table_frame(&ctx, WINDOW, &NATURAL, Vec::new());
+        let cells = table_frame(&ctx, WINDOW, &NATURAL, Vec::new());
+        (ctx, cells)
+    }
+
+    /// Drags a column's right edge, which runs midway through the gap after `cell`, then lets go.
+    fn drag_edge(ctx: &egui::Context, cell: egui::Rect, by: f32) {
+        use egui::{Event, Modifiers, PointerButton};
+        let start = egui::pos2(cell.right() + 4.0, cell.center().y);
+        let halfway = start + egui::vec2(by / 2.0, 0.0);
+        let end = start + egui::vec2(by, 0.0);
+        let moved = Event::PointerMoved;
+        let button = |pos, pressed| Event::PointerButton { pos, button: PointerButton::Primary, pressed, modifiers: Modifiers::NONE };
+        for event in [moved(start), button(start, true), moved(halfway), moved(end), button(end, false)] {
+            table_frame(ctx, WINDOW, &NATURAL, vec![event]);
+        }
+    }
+
+    #[test]
+    fn every_column_can_be_dragged_at_its_right_edge_and_stays_there() {
+        let (_, opened) = opened_table();
+        for (dragged, cell) in opened.iter().enumerate() {
+            let (ctx, _) = opened_table();
+            drag_edge(&ctx, *cell, -30.0);
+            table_frame(&ctx, WINDOW, &NATURAL, Vec::new());
+            let after = table_frame(&ctx, WINDOW, &NATURAL, Vec::new());
+            for (column, (was, now)) in opened.iter().zip(&after).enumerate() {
+                let want = if column == dragged { was.width() - 30.0 } else { was.width() };
+                assert!((now.width() - want).abs() < 1.0, "dragging column {dragged}: column {column} is {now:?}, was {was:?}");
+            }
+        }
+    }
+
+    #[test]
+    fn a_changed_fit_replaces_the_column_widths() {
+        let (ctx, opened) = opened_table();
+        drag_edge(&ctx, opened[0], -30.0);
+        let longer_name = table_frame(&ctx, WINDOW, &[200.0, 80.0, 80.0], Vec::new());
+        assert!((longer_name[0].width() - opened[0].width()).abs() < 1.0, "a longer name drops a dragged width: {longer_name:?}");
+        let wider = table_frame(&ctx, WINDOW, &[120.0, 200.0, 80.0], Vec::new());
+        let widths: Vec<f32> = wider.iter().map(|c| c.width().round()).collect();
+        assert!(widths.ends_with(&[200.0, 80.0]), "a longer cell widens its column: {widths:?}");
+        assert!(wider[2].right() < WINDOW, "the table still fits the window: {wider:?}");
+        let narrower = table_frame(&ctx, 400.0, &NATURAL, Vec::new());
+        assert!(narrower[2].right() < 400.0, "a narrower window refits the table: {narrower:?}");
+    }
+
+    #[test]
+    fn scrolling_sideways_keeps_dragged_widths() {
+        let (ctx, opened) = opened_table();
+        drag_edge(&ctx, opened[0], 100.0);
+        table_frame(&ctx, WINDOW, &NATURAL, Vec::new());
+        let dragged = table_frame(&ctx, WINDOW, &NATURAL, Vec::new());
+        assert!((dragged[0].width() - opened[0].width() - 100.0).abs() < 1.0, "the drag took: {dragged:?}");
+        for offset in [13.3, 27.77, 41.1, 0.6] {
+            scrolled_frame(&ctx, WINDOW, &NATURAL, offset, Vec::new());
+            let scrolled = scrolled_frame(&ctx, WINDOW, &NATURAL, offset, Vec::new());
+            assert!((scrolled[0].width() - dragged[0].width()).abs() < 1.0, "scrolled {offset}: {scrolled:?}");
+        }
+    }
 }

crates/ui-egui/src/host_save_tests.rs

@@ -0,0 +1,213 @@
+//! The web build framed by a page that keeps the files (`?host=parent`): what Save, Save As,
+//! the exports and Print hand that page, under which name, and whether it is a new file.
+#![allow(clippy::unwrap_used, clippy::expect_used)]
+
+use std::cell::RefCell;
+use std::rc::Rc;
+
+use serde_json::json;
+
+use super::{Services, SlideApp};
+use crate::Session;
+
+/// What the page was handed: (name, Save As, bytes).
+type Got = Rc<RefCell<Vec<(String, bool, Vec<u8>)>>>;
+
+/// The web app inside such a page, with `host_save` and `download` pointed at it as the bridge
+/// does; `fail` makes every save miss the page.
+fn host_app(fail: bool) -> (SlideApp, Got) {
+    let got: Got = Rc::default();
+    let (saves, downloads) = (got.clone(), got.clone());
+    let services = Services {
+        host_save: Some(Box::new(move |name: &str, bytes: &[u8], save_as: bool| {
+            if fail {
+                return Err("the page is gone".into());
+            }
+            saves.borrow_mut().push((name.to_string(), save_as, bytes.to_vec()));
+            Ok(())
+        })),
+        download: Some(Box::new(move |name: &str, bytes: &[u8]| downloads.borrow_mut().push((name.to_string(), false, bytes.to_vec())))),
+        ..Default::default()
+    };
+    // Host mode starts as the web shell starts it: an empty presentation for the page's file.
+    let mut app = SlideApp::new(Session::new(), services);
+    app.start_for_host().unwrap();
+    (app, got)
+}
+
+/// A .pptx with `slides` slides, as the page would send it.
+fn pptx(slides: usize) -> Vec<u8> {
+    let mut s = Session::with_new();
+    while s.doc().unwrap().doc.slides.len() < slides {
+        s.execute("slide.new", &json!({})).unwrap();
+    }
+    deckcraft_engine::cmd::file::save_bytes(&s.doc().unwrap().doc, "pptx").unwrap()
+}
+
+fn edit(app: &mut SlideApp) {
+    app.session.execute("slide.new", &json!({})).unwrap();
+    assert!(app.session.active().unwrap().is_dirty());
+}
+
+fn calls(got: &Got) -> Vec<(String, bool)> {
+    got.borrow().iter().map(|(n, s, _)| (n.clone(), *s)).collect()
+}
+
+fn path(app: &SlideApp) -> Option<String> {
+    app.session.active().and_then(|d| d.path.clone())
+}
+
+/// The bug this prevents: Save of a .pptx the page sent came back as `<name>.deckcraft`. Save
+/// now hands the page the opened file under its own name and format, not as a new file; Save As
+/// says it is a new file and becomes the file the next Save writes.
+#[test]
+fn host_saves_go_back_to_the_opened_file() {
+    let (mut app, got) = host_app(false);
+    app.open_from_host(Some("Lecture 3.pptx"), &pptx(2));
+    assert_eq!(app.session.documents().len(), 1, "the untouched blank presentation gave way");
+    edit(&mut app);
+    app.save();
+    assert!(!app.session.active().unwrap().is_dirty());
+    edit(&mut app);
+    app.save_as_dialog("deckcraft");
+    assert!(!app.session.active().unwrap().is_dirty());
+    edit(&mut app);
+    app.save();
+    let names = [("Lecture 3.pptx", false), ("Lecture 3.deckcraft", true), ("Lecture 3.deckcraft", false)];
+    assert_eq!(calls(&got), names.map(|(n, s)| (n.to_string(), s)));
+    // The first save is a .pptx that reopens with the edit in it.
+    let first = got.borrow()[0].2.clone();
+    assert!(first.windows(20).any(|w| w == b"ppt/presentation.xml"), "Save writes PowerPoint, not .deckcraft");
+    let reopened = deckcraft_engine::cmd::file::loaded_file("Lecture 3.pptx", &first).unwrap();
+    assert_eq!(reopened.doc.slides.len(), 3);
+}
+
+/// A presentation the page never sent is a new file, as Save As: the page must not overwrite a
+/// file of the same name. The next Save goes back to it.
+#[test]
+fn host_save_of_an_untitled_presentation_is_save_as() {
+    let (mut app, got) = host_app(false);
+    let name = format!("{}.deckcraft", app.session.active().unwrap().title());
+    edit(&mut app);
+    app.save();
+    edit(&mut app);
+    app.save();
+    assert_eq!(calls(&got), [(name.clone(), true), (name, false)]);
+}
+
+/// A presentation the user dropped (or picked with File › Open) didn't come from the page, so
+/// its name isn't one the page holds: Save makes a new file.
+#[test]
+fn a_file_the_page_never_sent_saves_as_a_new_file() {
+    let (mut app, got) = host_app(false);
+    app.open_or_insert_bytes("dropped.pptx", &pptx(1));
+    app.save();
+    assert_eq!(calls(&got), [("dropped.deckcraft".to_string(), true)]);
+}
+
+/// Exports and Print are copies: named after the presentation, not a new file, and the
+/// presentation keeps its own file and its unsaved changes.
+#[test]
+fn host_exports_and_print_are_copies() {
+    let (mut app, got) = host_app(false);
+    app.open_from_host(Some("deck.pptx"), &pptx(1));
+    edit(&mut app);
+    assert!(app.export_as("pdf", json!({})));
+    assert!(app.print_pdf(json!({})));
+    assert_eq!(calls(&got), [("deck.pdf".to_string(), false), ("deck.pdf".to_string(), false)]);
+    assert!(app.session.active().unwrap().is_dirty());
+    assert_eq!(path(&app).as_deref(), Some("deck.pptx"));
+}
+
+/// The page not getting the file is a failed save: the presentation keeps its changes.
+#[test]
+fn a_host_save_that_fails_leaves_the_presentation_unsaved() {
+    let (mut app, _) = host_app(true);
+    app.open_from_host(Some("deck.pptx"), &pptx(1));
+    edit(&mut app);
+    app.save();
+    assert!(app.session.active().unwrap().is_dirty());
+    assert!(app.status.as_ref().is_some_and(|(m, _)| m.contains("Couldn't save deck.pptx")));
+}
+
+/// Only an untouched start presentation gives way: one with changes stays open beside the file.
+#[test]
+fn an_edited_start_presentation_stays_open() {
+    let (mut app, _) = host_app(false);
+    edit(&mut app);
+    app.open_from_host(Some("deck.pptx"), &pptx(1));
+    assert_eq!(app.session.documents().len(), 2);
+    assert_eq!(path(&app).as_deref(), Some("deck.pptx"));
+}
+
+/// Only the first file from the page takes the start presentation's place. The bug this
+/// prevents: a file sent without a name opens untitled and unchanged, as the start presentation
+/// is, so the page's next file closed it.
+#[test]
+fn only_the_first_file_from_the_page_replaces_the_start_presentation() {
+    let (mut app, _) = host_app(false);
+    app.open_from_host(None, &pptx(2));
+    app.open_from_host(Some("deck.pptx"), &pptx(3));
+    let slides: Vec<usize> = app.session.documents().iter().map(|d| d.doc.slides.len()).collect();
+    assert_eq!(slides, [2, 3], "the file sent without a name stays open beside the next one");
+    assert_eq!(path(&app).as_deref(), Some("deck.pptx"));
+}
+
+/// The command palette runs `file.save` by id. With a file of its own the engine would write to
+/// that path, which a browser can't; in host mode it goes to the page like Ctrl+S.
+#[test]
+fn palette_save_goes_to_the_page() {
+    let (mut app, got) = host_app(false);
+    app.open_from_host(Some("deck.pptx"), &pptx(1));
+    edit(&mut app);
+    let r = app.run("file.save", json!({})).unwrap();
+    assert_eq!(r["path"], "deck.pptx");
+    assert_eq!(calls(&got), [("deck.pptx".to_string(), false)]);
+    assert!(!app.session.active().unwrap().is_dirty());
+}
+
+/// A file the page sent without a name, or with a name that isn't a presentation's, has no file
+/// of its own: Save is a new `.deckcraft`, never an overwrite of an invented `Presentation.pptx`.
+#[test]
+fn a_file_sent_without_a_presentation_name_saves_as_a_new_file() {
+    for (name, saved) in [(None, "Presentation.deckcraft"), (Some("Talk"), "Talk.deckcraft")] {
+        let (mut app, got) = host_app(false);
+        app.open_from_host(name, &pptx(2));
+        assert_eq!(app.session.documents().len(), 1, "{name:?}");
+        assert_eq!(app.session.active().unwrap().doc.slides.len(), 2, "{name:?}");
+        assert_eq!(path(&app), None, "{name:?}");
+        app.save();
+        assert_eq!(calls(&got), [(saved.to_string(), true)], "{name:?}");
+    }
+}
+
+/// An outline from the page opens as a new untitled presentation, as File › Open does on the
+/// desktop: the blank start presentation gives way, and Save is a new file.
+#[test]
+fn an_outline_from_the_page_opens_as_a_new_presentation() {
+    let (mut app, got) = host_app(false);
+    app.open_from_host(Some("notes.md"), b"# One\n\n# Two\n\n# Three\n");
+    assert_eq!(app.session.documents().len(), 1);
+    assert_eq!(app.session.active().unwrap().doc.slides.len(), 3);
+    assert_eq!(path(&app), None);
+    app.save();
+    assert_eq!(calls(&got), [("notes.deckcraft".to_string(), true)]);
+}
+
+/// A damaged file from the page opens as an untitled "(Repaired)" copy, so Save is a new file
+/// and can't overwrite the page's original with the emptied media.
+#[test]
+fn a_damaged_file_from_the_page_saves_as_a_new_repaired_file() {
+    let mut p = deckcraft_model::Presentation::default();
+    p.add_media("a.png", "image/png", b"PICTURE-BYTES-0123456789".to_vec());
+    let mut bad = deckcraft_engine::cmd::file::save_bytes(&p, "deckcraft").unwrap();
+    // Pictures are stored as they are, so flipping a byte breaks the entry's CRC.
+    let at = bad.windows(13).position(|w| w == b"PICTURE-BYTES").unwrap();
+    bad[at] ^= 0xff;
+    let (mut app, got) = host_app(false);
+    app.open_from_host(Some("talk.deckcraft"), &bad);
+    assert_eq!(path(&app), None);
+    assert!(app.session.active().unwrap().title().ends_with("(Repaired)"));
+    app.save();
+    assert_eq!(calls(&got), [("talk (Repaired).deckcraft".to_string(), true)]);
+}

crates/ui-egui/src/lib.rs

@@ -72,7 +72,7 @@ pub use panels::notes;
 pub use panels::selpane;
 pub use panels::thumbs;
 pub use ribbon::qat;
-pub use services::{DownloadFn, Inbox, InboxEvent, InboxFile, OpenAsyncFn, PickFn, ReadFn, Services, WriteFn};
+pub use services::{DownloadFn, HostSaveFn, Inbox, InboxEvent, InboxFile, OpenAsyncFn, PickFn, ReadFn, Services, WriteFn};
 use state::{FilePlace, FilePurpose, ImeDescriptorKey, ImeDestination, ImeTerminalStamp};
 pub use state::{RECENT_MAX, UiState, ViewMode, ZOOM_RANGE};
 
@@ -335,6 +335,9 @@ pub struct SlideApp {
     next_file_id: u64,
     /// Picks and drops whose bytes have not arrived yet.
     pending_files: Vec<PendingFile>,
+    /// The empty presentation host mode starts with ([`SlideApp::start_for_host`]), until the
+    /// first file the page sends takes its place.
+    host_start: Option<u64>,
     /// Owner/generation/cause bookkeeping for the canvas text IME producer.
     ime_tracker: egui::ime_context::ImeContextTracker,
     /// Canvas IME geometry for this pass: the caret while editing, or the selected shape.
@@ -487,5 +490,8 @@ mod datetime_tests;
 #[cfg(test)]
 mod inbox_tests;
 
+#[cfg(test)]
+mod host_save_tests;
+
 #[cfg(test)]
 mod tests;

crates/ui-egui/src/panels/thumbs.rs

@@ -112,6 +112,21 @@ pub fn show(app: &mut SlideApp, ui: &mut Ui) {
     }
 }
 
+/// Slide index -> the first section starting there, built once instead of searched per slide.
+fn section_starts(doc: &deckcraft_model::Presentation) -> std::collections::HashMap<usize, usize> {
+    let mut index_of = std::collections::HashMap::new();
+    for (i, s) in doc.slides.iter().enumerate() {
+        index_of.entry(s.id).or_insert(i);
+    }
+    let mut starts = std::collections::HashMap::new();
+    for (si, s) in doc.sections.iter().enumerate() {
+        if let Some(&i) = s.slides.first().and_then(|id| index_of.get(id)) {
+            starts.entry(i).or_insert(si);
+        }
+    }
+    starts
+}
+
 /// Render the scrollable thumbnail list, scrolling the current slide into view when it changes.
 fn list(app: &mut SlideApp, ui: &mut Ui) {
     let t = Tokens::get(ui.ctx());
@@ -135,11 +150,10 @@ fn list(app: &mut SlideApp, ui: &mut Ui) {
     let ppp = ui.ctx().pixels_per_point();
     let mut budget = 3u32;
     let mut rects = vec![];
-    let section_starts: Vec<(usize, usize)> =
-        doc.sections.iter().enumerate().filter_map(|(si, s)| s.slides.first().and_then(|id| doc.slide_index(*id)).map(|i| (i, si))).collect();
+    let section_starts = section_starts(&doc);
     let mut need_more = false;
     for i in 0..doc.slides.len() {
-        if let Some((_, si)) = section_starts.iter().find(|(start, _)| *start == i)
+        if let Some(si) = section_starts.get(&i)
             && let Some(sec) = doc.sections.get(*si)
         {
             ui.add_space(4.0);
@@ -205,7 +219,7 @@ fn list(app: &mut SlideApp, ui: &mut Ui) {
         // Only rows in view (plus a little margin) ask for a thumbnail: with every row asking, a
         // deck bigger than the thumbnail cache evicts its own thumbnails and never settles (#969).
         let near = ui.clip_rect().expand2(vec2(0.0, 2.0 * row.height())).intersects(row);
-        let tex = if near { app.textures.thumb(ui.ctx(), &doc, i, wpx, &mut budget) } else { None };
+        let tex = if near { app.textures.thumb(ui.ctx(), &doc, i, wpx, app.ui.grayscale, &mut budget) } else { None };
         match tex {
             Some(tex) => {
                 p.image(
@@ -434,6 +448,26 @@ mod tests {
         h
     }
 
+    #[test]
+    fn section_starts_map_each_first_slide_to_its_first_section() {
+        let mut s = Session::with_new();
+        for _ in 0..3 {
+            s.execute("slide.new", &json!({})).unwrap();
+        }
+        let mut doc = (*s.active().unwrap().doc).clone();
+        let ids: Vec<_> = doc.slides.iter().map(|sl| sl.id).collect();
+        doc.sections = vec![
+            deckcraft_model::Section { name: "a".into(), slides: vec![ids[0], ids[1]] },
+            deckcraft_model::Section { name: "dup".into(), slides: vec![ids[0]] },
+            deckcraft_model::Section { name: "c".into(), slides: vec![ids[2]] },
+            deckcraft_model::Section { name: "empty".into(), slides: vec![] },
+        ];
+        let starts = section_starts(&doc);
+        assert_eq!(starts.get(&0), Some(&0), "the first section starting at a slide wins");
+        assert_eq!(starts.get(&2), Some(&2));
+        assert_eq!(starts.len(), 2);
+    }
+
     /// Vertical scroll offset of the thumbnail pane, as recorded each frame by `show`.
     fn thumbs_scroll(h: &Harness<'_, SlideApp>) -> f32 {
         h.state().ui.thumbs_scroll

crates/ui-egui/src/presenter.rs

@@ -49,10 +49,15 @@ pub struct Snapshot {
     pub paused: bool,
     pub notes_px: f32,
     pub blank: Option<String>,
+    /// All slides is open in the presenter window (#1866); the audience keeps the current slide.
     pub grid: bool,
     pub zoom_armed: bool,
     pub current: Option<Preview>,
     pub next: Option<Preview>,
+    /// The All slides thumbnails, in slide order, while `grid` is on. `None` in a sent delta
+    /// means "unchanged since the last snapshot the window received".
+    #[serde(default)]
+    pub slides: Option<Vec<Preview>>,
 }
 
 /// Images acknowledged by a successful transport send, never merely attempted images.
@@ -60,6 +65,7 @@ pub struct Snapshot {
 pub struct DeltaCache {
     current: Option<Preview>,
     next: Option<Preview>,
+    slides: Option<Vec<Preview>>,
     token: String,
 }
 impl DeltaCache {
@@ -75,6 +81,12 @@ impl DeltaCache {
         let next_changed = fresh || self.next != snapshot.next;
         let current = snapshot.current.clone();
         let next = snapshot.next.clone();
+        let slides = snapshot.slides.clone();
+        if !fresh && self.slides == slides {
+            snapshot.slides = None;
+        } else if snapshot.slides.is_none() {
+            snapshot.slides = Some(Vec::new());
+        }
         if !current_changed {
             snapshot.current = None;
         }
@@ -84,14 +96,28 @@ impl DeltaCache {
         send(snapshot, current_changed, next_changed)?;
         self.current = current;
         self.next = next;
+        self.slides = slides;
         self.token = token.to_owned();
         Ok(())
     }
 }
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 pub enum Command {
-    Key { name: String, command: bool, shift: bool, alt: bool, ctrl: bool },
-    Zoom { x: f32, y: f32 },
+    Key {
+        name: String,
+        command: bool,
+        shift: bool,
+        alt: bool,
+        ctrl: bool,
+    },
+    Zoom {
+        x: f32,
+        y: f32,
+    },
+    /// A slide chosen in the presenter window's All slides grid (#1866).
+    Goto {
+        slide: usize,
+    },
     End,
 }
 /// Implemented by the browser host. Native hosts retain the existing egui viewport.
@@ -112,6 +138,8 @@ pub struct View {
     next: Option<egui::TextureHandle>,
     previous_current: Option<Preview>,
     previous_next: Option<Preview>,
+    grid_source: Option<Vec<Preview>>,
+    grid: Vec<Option<egui::TextureHandle>>,
 }
 impl View {
     /// Install the same interface and dynamic fallback fonts as SlideApp before layout.
@@ -147,6 +175,10 @@ impl View {
                 .collect::<Vec<_>>()
         });
         for (key, modifiers) in keys {
+            if snapshot.grid && matches!(key, egui::Key::Space | egui::Key::Enter) {
+                // A focused thumbnail takes these to choose its slide; the show ignores them while the grid is open.
+                continue;
+            }
             // Consume once before widgets see Space/Enter, avoiding a second button activation.
             ui.input_mut(|i| i.consume_key(modifiers, key));
             commands.push(Command::Key {
@@ -200,6 +232,11 @@ impl View {
             }
         });
         ui.separator();
+        if snapshot.grid {
+            // All slides opens here, as in the desktop Presenter View; the audience keeps the current slide.
+            self.grid_ui(ui, snapshot, &mut commands);
+            return commands;
+        }
         ui.columns(2, |columns| {
             let left = &mut columns[0];
             if snapshot.ended {
@@ -227,9 +264,6 @@ impl View {
             if snapshot.zoom_armed {
                 left.label("Click the preview to zoom.");
             }
-            if snapshot.grid {
-                left.label("Choose a slide in the audience window, or press G to return.");
-            }
             let right = &mut columns[1];
             right.label("Next");
             if let Some(texture) = &self.next {
@@ -260,6 +294,43 @@ impl View {
         commands
     }
 }
+impl View {
+    fn grid_ui(&mut self, ui: &mut egui::Ui, snapshot: &Snapshot, commands: &mut Vec<Command>) {
+        let slides = snapshot.slides.as_deref().unwrap_or_default();
+        if self.grid_source.as_deref() != Some(slides) {
+            self.grid_source = Some(slides.to_vec());
+            self.grid = slides
+                .iter()
+                .enumerate()
+                .map(|(i, p)| p.image().map(|image| ui.ctx().load_texture(format!("remote-grid-{i}"), image, egui::TextureOptions::LINEAR)))
+                .collect();
+        }
+        ui.heading("All slides");
+        ui.label("Choose a slide to show it, or press G to return.");
+        if snapshot.total > crate::show::GRID_CAP {
+            ui.label(format!("First {} slides", crate::show::GRID_CAP));
+        }
+        egui::ScrollArea::vertical().show(ui, |ui| {
+            ui.horizontal_wrapped(|ui| {
+                for (i, texture) in self.grid.iter().enumerate() {
+                    let size = egui::vec2(160.0, 90.0);
+                    let label = format!("{}", i + 1);
+                    let label = if i == snapshot.slide { egui::RichText::new(label).strong() } else { egui::RichText::new(label) };
+                    let response = match texture {
+                        Some(t) => ui.add(egui::Button::image_and_text(
+                            egui::Image::new(t).fit_to_exact_size(fit_preview(t.size_vec2(), size.x, size.y)),
+                            label,
+                        )),
+                        None => ui.add_sized(size, egui::Button::new(label)),
+                    };
+                    if response.clicked() {
+                        commands.push(Command::Goto { slide: i });
+                    }
+                }
+            });
+        });
+    }
+}
 fn fit_preview(size: egui::Vec2, width: f32, height: f32) -> egui::Vec2 {
     size * (width.max(1.0) / size.x.max(1.0)).min(height.max(1.0) / size.y.max(1.0))
 }
@@ -282,6 +353,7 @@ mod tests {
             zoom_armed: false,
             current: Some(Preview { width: 1, height: 1, rgba: vec![255; 4] }),
             next: Some(Preview { width: 1, height: 1, rgba: vec![0; 4] }),
+            slides: None,
         }
     }
 
@@ -418,6 +490,7 @@ mod tests {
             zoom_armed: false,
             current: None,
             next: None,
+            slides: None,
         };
         let mut h = egui_kittest::Harness::builder().with_size(egui::vec2(1000.0, 700.0)).build_ui_state(
             |ui, (view, snapshot, sent): &mut (View, Snapshot, Vec<Command>)| {
@@ -437,6 +510,30 @@ mod tests {
         assert!(matches!(h.state().2.last(), Some(Command::Key { name, .. }) if name == egui::Key::Space.name()));
     }
 
+    #[test]
+    fn all_slides_opens_in_the_popup_and_picks_a_slide() {
+        use egui_kittest::kittest::Queryable;
+        let thumb = Preview { width: 16, height: 9, rgba: vec![200; 16 * 9 * 4] };
+        let mut snapshot = snapshot();
+        snapshot.total = 3;
+        snapshot.grid = true;
+        snapshot.slides = Some(vec![thumb.clone(), thumb.clone(), thumb]);
+        let mut h = egui_kittest::Harness::builder().with_size(egui::vec2(1000.0, 700.0)).build_ui_state(
+            |ui, (view, snapshot, sent): &mut (View, Snapshot, Vec<Command>)| {
+                sent.extend(view.ui(ui, snapshot));
+            },
+            (View::default(), snapshot, Vec::new()),
+        );
+        h.run_steps(2);
+        assert!(h.query_by_label("Notes").is_none(), "the grid replaces the presenter panes, as on desktop (#1866)");
+        h.get_by_label("3").click();
+        h.run_steps(2);
+        assert_eq!(h.state().2, vec![Command::Goto { slide: 2 }]);
+        h.key_press(egui::Key::Enter);
+        h.run_steps(2);
+        assert!(!h.state().2.iter().any(|c| matches!(c, Command::Key { .. })), "Enter is left to the focused thumbnail");
+    }
+
     #[test]
     fn previews_are_bounded_and_bad_dimensions_are_rejected() {
         let image = egui::ColorImage::filled([1280, 720], egui::Color32::RED);

crates/ui-egui/src/services.rs

@@ -11,6 +11,10 @@ pub type OpenAsyncFn = Box<dyn FnMut(&str, u64)>;
 
 pub type DownloadFn = Box<dyn FnMut(&str, &[u8])>;
 
+/// [`Services::host_save`]: `(file name, bytes, save_as)`. An error means the page didn't get
+/// the file, and the save failed.
+pub type HostSaveFn = Box<dyn FnMut(&str, &[u8], bool) -> Result<(), String>>;
+
 /// A file the host finished reading for the request `id` from [`SlideApp::begin_external_file`].
 #[derive(Clone, Debug)]
 pub struct InboxFile {
@@ -49,6 +53,15 @@ pub struct Services {
     pub open_async: Option<OpenAsyncFn>,
     /// Hand bytes to the user as a named file (browser download).
     pub download: Option<DownloadFn>,
+    /// Web, framed by a page that keeps the files (`?host=parent`): Save and Save As hand the
+    /// presentation to that page instead of downloading it, with whether it is a new file
+    /// ([`HostSaveFn`]). Save writes a presentation the page sent back under its own name and
+    /// format, as the desktop app writes back to the file it opened; a presentation the page
+    /// never sent (an untitled one, a repaired copy) goes as a new `.deckcraft` file, as Save
+    /// suggests on the desktop. Save As (.pptx or .deckcraft) is always a new file. Either way the
+    /// presentation is then that file, and the next Save goes to it. Exports and Print still go
+    /// through `download`, which the host also points at the page: they are copies.
+    pub host_save: Option<HostSaveFn>,
     pub inbox: Option<Inbox>,
     /// Image on the system clipboard (PNG bytes), when the host can read one.
     pub clipboard_image: Option<Box<dyn FnMut() -> Option<Vec<u8>>>>,

crates/ui-egui/src/show.rs

@@ -18,6 +18,7 @@ mod presenter;
 mod render;
 mod ui;
 mod zoom;
+pub(crate) use zoom::GRID_CAP;
 
 #[cfg(test)]
 use media::{on_screen, pointer_on_media_bar, shown_slide_rect, slide_media_bars};
@@ -65,6 +66,8 @@ pub struct Show {
     preview_spawns: usize,
     remote_preview: Option<crate::presenter::Preview>,
     remote_next: Option<(usize, crate::presenter::Preview)>,
+    /// All slides thumbnails sent to the web presenter window while its grid is open (#1866).
+    remote_grid: Vec<crate::presenter::Preview>,
     remote_sent: f64,
     remote_opened: bool,
     /// The next slide's first frame, rendered in the background while this one is shown so
@@ -237,6 +240,7 @@ impl Show {
             preview_spawns: 0,
             remote_preview: None,
             remote_next: None,
+            remote_grid: vec![],
             remote_sent: f64::NEG_INFINITY,
             remote_opened: false,
             prefetch: None,

crates/ui-egui/src/show/tests.rs

@@ -1132,6 +1132,8 @@ fn remote_presenter_uses_the_audience_state_and_closes_with_the_show() {
         opens: usize,
         closes: usize,
         commands: Vec<Command>,
+        last: Option<Snapshot>,
+        gone: bool,
     }
     struct Mock(Rc<RefCell<Bridge>>);
     impl Host for Mock {
@@ -1140,12 +1142,14 @@ fn remote_presenter_uses_the_audience_state_and_closes_with_the_show() {
             Ok(())
         }
         fn is_open(&self) -> bool {
-            true
+            !self.0.borrow().gone
         }
         fn commands(&mut self) -> Vec<Command> {
             std::mem::take(&mut self.0.borrow_mut().commands)
         }
-        fn update(&mut self, _: Snapshot) {}
+        fn update(&mut self, snapshot: Snapshot) {
+            self.0.borrow_mut().last = Some(snapshot);
+        }
         fn close(&mut self) {
             self.0.borrow_mut().closes += 1;
         }
@@ -1173,6 +1177,39 @@ fn remote_presenter_uses_the_audience_state_and_closes_with_the_show() {
         h.run_steps(2);
         assert_eq!(h.state().show.as_ref().unwrap().state.slide, slide);
     }
+    // #1864: the web popup's Previous/Next buttons send the DOM key names.
+    for (name, slide) in [("ArrowRight", 1), ("ArrowLeft", 0)] {
+        bridge.borrow_mut().commands.push(Command::Key { name: name.into(), command: false, shift: false, alt: false, ctrl: false });
+        h.run_steps(2);
+        assert_eq!(h.state().show.as_ref().unwrap().state.slide, slide, "{name}");
+    }
+    // #1866: All slides opens in the web Presenter View, as on desktop; the audience keeps its slide.
+    bridge.borrow_mut().commands.push(Command::Key { name: "G".into(), command: false, shift: false, alt: false, ctrl: false });
+    h.run_steps(2);
+    let show = h.state().show.as_ref().unwrap();
+    assert!(show.presenter_grid && !show.grid, "G from the popup opens its own grid, not the audience's");
+    for _ in 0..20 {
+        h.step();
+        std::thread::sleep(std::time::Duration::from_millis(15));
+    }
+    let last = bridge.borrow().last.clone().unwrap();
+    assert!(last.grid);
+    assert_eq!(last.slides.as_ref().map(Vec::len), Some(3), "the popup gets a thumbnail per slide");
+    assert!(last.slides.iter().flatten().all(|p| p.width.max(p.height) <= 96), "thumbnails stay small enough for one message");
+    assert!(last.current.is_none() && last.next.is_none(), "the grid replaces both previews");
+    bridge.borrow_mut().commands.push(Command::Goto { slide: 2 });
+    h.run_steps(2);
+    let show = h.state().show.as_ref().unwrap();
+    assert!(!show.presenter_grid && !show.grid);
+    assert_eq!(show.state.slide, 2);
+    // Closing the popup with its grid open must not hold auto-advance for the rest of the show.
+    bridge.borrow_mut().commands.push(Command::Key { name: "G".into(), command: false, shift: false, alt: false, ctrl: false });
+    h.run_steps(2);
+    assert!(h.state().show.as_ref().unwrap().presenter_grid);
+    bridge.borrow_mut().gone = true;
+    h.run_steps(2);
+    assert!(!h.state().show.as_ref().unwrap().presenter_grid);
+    bridge.borrow_mut().gone = false;
     bridge.borrow_mut().commands.push(Command::End);
     h.run_steps(2);
     assert!(h.state().show.is_none());

crates/ui-egui/src/show/ui.rs

@@ -80,6 +80,10 @@ pub fn ui(app: &mut SlideApp, ui: &mut Ui) {
         && !show.reading
         && let Some(host) = app.services.presenter.as_mut()
     {
+        if show.remote_opened && show.presenter_grid && !host.is_open() {
+            // A grid left open in the closed popup would hold auto-advance for the rest of the show.
+            show.presenter_grid = false;
+        }
         if !show.remote_opened {
             show.remote_opened = true;
             if let Err(message) = host.open() {
@@ -94,11 +98,20 @@ pub fn ui(app: &mut SlideApp, ui: &mut Ui) {
                     show.zoom_arm = false;
                 }
                 crate::presenter::Command::Key { name, command, shift, alt, ctrl } => {
-                    if let Some(key) = egui::Key::ALL.iter().copied().find(|key| key.name() == name) {
+                    if let Some(key) = egui::Key::from_name(&name) {
                         let modifiers = egui::Modifiers { command, shift, alt, ctrl, mac_cmd: command && !ctrl };
-                        out.keep &= handle_keys(&mut show, &doc, now, vec![(key, modifiers)], false).0;
+                        // The popup is the Presenter View: G opens All slides there, not on the audience screen (#1866).
+                        out.keep &= handle_keys(&mut show, &doc, now, vec![(key, modifiers)], true).0;
                     }
                 }
+                crate::presenter::Command::Goto { slide } if show.presenter_grid && slide < doc.slides.len() => {
+                    show.presenter_grid = false;
+                    show.blank = None;
+                    show.zoom = None;
+                    show.zoom_arm = false;
+                    let action = show.state.goto(&doc, slide);
+                    out.keep &= show.apply(action, &doc, now);
+                }
                 _ => {}
             }
         }
@@ -143,6 +156,20 @@ pub fn ui(app: &mut SlideApp, ui: &mut Ui) {
                 );
                 show.remote_next = crate::presenter::Preview::from_image(&crate::textures::to_color_image(&image, false)).map(|image| (n, image));
             }
+            if !show.presenter_grid {
+                show.remote_grid.clear();
+            } else if show.remote_grid.len() < grid_indices(doc.slides.len()).len() {
+                // A few thumbnails per update keep the audience window responsive on the web.
+                for i in grid_indices(doc.slides.len()).into_iter().skip(show.remote_grid.len()).take(4) {
+                    // At most 96 px on the long side: 48 thumbnails stay well under the popup's message limit.
+                    let (w, h) = (doc.slide_size.width.max(1.0), doc.slide_size.height.max(1.0));
+                    let scale = REMOTE_THUMB / w.max(h);
+                    let size = (((w * scale).round() as u32).max(1), ((h * scale).round() as u32).max(1));
+                    let image = deckcraft_render::render_slide(&doc, i, &RenderOpts { scale, size: Some(size), ..Default::default() });
+                    let preview = crate::presenter::Preview::from_image(&crate::textures::to_color_image(&image, false));
+                    show.remote_grid.push(preview.unwrap_or(crate::presenter::Preview { width: 1, height: 1, rgba: vec![0; 4] }));
+                }
+            }
             host.update(crate::presenter::Snapshot {
                 slide: show.state.slide,
                 total: doc.slides.len(),
@@ -152,10 +179,12 @@ pub fn ui(app: &mut SlideApp, ui: &mut Ui) {
                 paused: show.timer.paused(),
                 notes_px: show.notes_px,
                 blank: show.blank_name().map(str::to_owned),
-                grid: show.grid,
+                grid: show.presenter_grid,
                 zoom_armed: show.zoom_arm,
-                current: show.remote_preview.clone(),
-                next: show.remote_next.as_ref().filter(|(n, _)| Some(*n) == next).map(|(_, image)| image.clone()),
+                // The grid replaces both previews in the popup; leaving them out keeps one message small.
+                current: show.remote_preview.clone().filter(|_| !show.presenter_grid),
+                next: show.remote_next.as_ref().filter(|(n, _)| Some(*n) == next && !show.presenter_grid).map(|(_, image)| image.clone()),
+                slides: show.presenter_grid.then(|| show.remote_grid.clone()),
             });
             show.remote_sent = now;
         }
@@ -164,6 +193,9 @@ pub fn ui(app: &mut SlideApp, ui: &mut Ui) {
     finish(app, show, &f, out.keep);
 }
 
+/// Longest side of an All slides thumbnail sent to the web presenter window (#1866).
+const REMOTE_THUMB: f64 = 96.0;
+
 fn paint_hidden(ui: &Ui, doc: &Presentation, show: &Show) {
     if show.started {
         let full = ui.max_rect();

crates/ui-egui/src/show/zoom.rs

@@ -182,7 +182,7 @@ const WHEEL_NOTCHES_PER_DOUBLING: f32 = 4.0;
 /// PowerPoint's slide show magnifier goes up to 400%.
 const WHEEL_ZOOM_MAX: f32 = 4.0;
 
-pub(super) const GRID_CAP: usize = 48;
+pub(crate) const GRID_CAP: usize = 48;
 
 const TOOL_BAR_W: f32 = 520.0;
 

crates/ui-egui/src/sorter.rs

@@ -209,7 +209,8 @@ fn place_slides(app: &mut SlideApp, ui: &mut Ui, g: &Grid<'_>, budget: &mut u32,
                 // Only cells in view (plus a little margin) ask for a thumbnail, so a deck bigger
                 // than the thumbnail cache does not evict its own thumbnails forever (#969).
                 let near = ui.clip_rect().expand2(vec2(0.0, 2.0 * cell.height())).intersects(cell);
-                let tex = if near { app.textures.thumb(ui.ctx(), g.doc, i, (img.width() * ppp).round() as u32, budget) } else { None };
+                let tex =
+                    if near { app.textures.thumb(ui.ctx(), g.doc, i, (img.width() * ppp).round() as u32, app.ui.grayscale, budget) } else { None };
                 match tex {
                     Some(tex) => {
                         p.image(tex.id(), img, Rect::from_min_max(pos2(0.0, 0.0), pos2(1.0, 1.0)), Color32::WHITE);
@@ -391,7 +392,7 @@ pub fn notes_page(app: &mut SlideApp, ui: &mut Ui) {
     }
     let ppp = ui.ctx().pixels_per_point();
     let mut budget = 2;
-    if let Some(tex) = app.textures.thumb(ui.ctx(), &doc, idx, (srect.width() * ppp).round() as u32, &mut budget) {
+    if let Some(tex) = app.textures.thumb(ui.ctx(), &doc, idx, (srect.width() * ppp).round() as u32, app.ui.grayscale, &mut budget) {
         ui.painter().image(tex.id(), srect, Rect::from_min_max(pos2(0.0, 0.0), pos2(1.0, 1.0)), Color32::WHITE);
     }
     ui.painter().rect_stroke(srect, CornerRadius::ZERO, Stroke::new(1.0, Color32::GRAY), egui::StrokeKind::Outside);
@@ -476,7 +477,7 @@ fn outline_estimate(s: &deckcraft_model::Slide) -> f32 {
     let lines: usize = s
         .shapes
         .iter()
-        .filter(|x| !x.ph_type().is_some_and(|k| k.is_title()))
+        .filter(|x| !x.ph_type().is_some_and(|k| k.is_title() || k.is_footer_kind()))
         .filter_map(|x| x.text.as_ref())
         .filter(|tb| !tb.is_empty())
         .map(|tb| tb.paragraphs.len().max(1))
@@ -512,7 +513,8 @@ fn outline_slide(app: &mut SlideApp, ui: &mut Ui, t: &Tokens, i: usize, s: &deck
             ui.data_mut(|d| d.insert_temp(id, v));
         }
     });
-    for sh in s.shapes.iter().filter(|x| !x.ph_type().is_some_and(|k| k.is_title())) {
+    // Footer, date and slide-number placeholders are not outline text, as in PowerPoint.
+    for sh in s.shapes.iter().filter(|x| !x.ph_type().is_some_and(|k| k.is_title() || k.is_footer_kind())) {
         let Some(tb) = &sh.text else { continue };
         if tb.is_empty() {
             continue;

crates/ui-egui/src/sorter/ui_tests.rs

@@ -259,3 +259,24 @@ fn shift_and_ctrl_shift_clicks_select_ranges() {
     click(&mut h, 4, Modifiers::COMMAND | Modifiers::SHIFT);
     assert_eq!(selected(&h), vec![0, 2, 3]);
 }
+
+/// The outline view lists a slide's title and body text, not its footer, date and slide-number
+/// placeholders, as PowerPoint's does: turning them on leaves the slide's outline block as it was.
+#[test]
+fn the_outline_view_leaves_footer_date_and_slide_number_out() {
+    let mut s = Session::with_new();
+    s.execute("slide.new", &json!({"layout": "titleAndContent", "title": "Agenda", "body": "First point\nSecond point"})).unwrap();
+    let slide = |s: &Session| {
+        let st = s.doc().unwrap();
+        st.doc.slides[st.selection.slide].clone()
+    };
+    let plain = super::outline_estimate(&slide(&s));
+    s.execute(
+        "design.headerFooter",
+        &json!({"footer": true, "footerText": "Company Confidential", "slideNumber": true, "date": true, "dateText": "1 May 2026"}),
+    )
+    .unwrap();
+    let with_footer = slide(&s);
+    assert!(with_footer.shapes.iter().any(|x| x.ph_type().is_some_and(|k| k.is_footer_kind())), "the footers are on the slide");
+    assert_eq!(super::outline_estimate(&with_footer), plain);
+}

crates/ui-egui/src/textures.rs

@@ -361,9 +361,19 @@ impl Textures {
         self.thumbs.clear();
     }
 
-    /// A thumbnail texture; renders at most `budget` new thumbnails per frame (returns None when
-    /// it is over budget, so the caller draws a placeholder and asks for another frame).
-    pub fn thumb(&mut self, ctx: &egui::Context, p: &Presentation, index: usize, width_px: u32, budget: &mut u32) -> Option<TextureHandle> {
+    /// A thumbnail texture; renders at most `budget` new thumbnails per frame. Over budget it
+    /// returns the slide's previous thumbnail if there is one (and asks for another frame), else
+    /// None, so the caller draws a placeholder.
+    /// When `grayscale` is true, the thumbnail renders in black-and-white (matching Grayscale view).
+    pub fn thumb(
+        &mut self,
+        ctx: &egui::Context,
+        p: &Presentation,
+        index: usize,
+        width_px: u32,
+        grayscale: bool,
+        budget: &mut u32,
+    ) -> Option<TextureHandle> {
         let slide = p.slides.get(index)?.clone();
         let master = master_of(p, &slide);
         let h = (width_px as f64 * p.slide_size.height / p.slide_size.width.max(1.0)).round().max(1.0) as u32;
@@ -372,7 +382,7 @@ impl Textures {
             master: master.as_ref().map(|m| Arc::as_ptr(m) as usize).unwrap_or(0),
             size: (width_px, h),
             edit: false,
-            extra: 0,
+            extra: grayscale as u64,
             want: Region::slide(width_px, h),
             editing_text: None,
         };
@@ -385,7 +395,8 @@ impl Textures {
             return Some(e.tex.clone());
         }
         if *budget == 0 {
-            // Keep showing the stale thumbnail while the new one waits.
+            // Keep showing the stale thumbnail while the new one waits; request a repaint to finish rendering.
+            ctx.request_repaint();
             return self.thumbs.get(&key.slide).map(|e| e.tex.clone());
         }
         *budget -= 1;
@@ -393,7 +404,7 @@ impl Textures {
         let scale = tw as f64 / p.slide_size.width.max(1.0);
         let img = deckcraft_render::render_slide(p, index, &RenderOpts { scale, size: Some((tw, th)), threads: 0, ..Default::default() });
         self.thumb_renders += 1;
-        let tex = upload_editor(ctx, format!("thumb-{index}"), to_color_image(&img, false));
+        let tex = upload_editor(ctx, format!("thumb-{index}"), to_color_image(&img, grayscale));
         // Drop the old entry for this slide address; entries for slides that no longer exist age out.
         let region = key.want;
         self.thumbs.insert(key.slide, Entry { key, tex: tex.clone(), region, _slide: slide, _master: master, stamp: clock });
@@ -433,6 +444,20 @@ mod tests {
         assert_eq!(device_pixel_rect(aligned, ppp), aligned);
     }
 
+    #[test]
+    fn to_color_image_turns_colors_to_grayscale_when_flag_is_set() {
+        let img = deckcraft_render::Image { width: 2, height: 1, pixels: vec![0, 0, 255, 255, 255, 0, 0, 255] };
+        let color = super::to_color_image(&img, false);
+        assert_eq!(color.pixels[0], egui::Color32::from_rgba_premultiplied(0, 0, 255, 255));
+        assert_eq!(color.pixels[1], egui::Color32::from_rgba_premultiplied(255, 0, 0, 255));
+
+        let gray = super::to_color_image(&img, true);
+        assert_eq!(gray.pixels[0].r(), gray.pixels[0].g());
+        assert_eq!(gray.pixels[0].g(), gray.pixels[0].b());
+        assert_eq!(gray.pixels[1].r(), gray.pixels[1].g());
+        assert_eq!(gray.pixels[1].g(), gray.pixels[1].b());
+    }
+
     #[test]
     fn a_bad_scale_does_not_move_the_rect() {
         let r = Rect::from_min_size(pos2(3.0, 4.0), vec2(10.0, 12.0));

packaging/web/README.md

@@ -65,12 +65,75 @@ Local test: `python3 -m http.server 8765` inside the folder, then open http://lo
 - The app fills the iframe and follows its size, so size the iframe and not the app.
 - Keyboard shortcuts go to the iframe after the user clicks into it, as with any embedded app.
 - **Cross-origin embeds** work. The web build keeps no preferences between visits; it starts
-  with the sample deck (or `?blank`) every time.
+  with the sample deck (or `?blank`) every time. Opening and saving through the page
+  (`?host=parent`, below) needs the same origin.
 - **Sandboxed iframes** need at least
   `sandbox="allow-scripts allow-same-origin allow-downloads allow-popups"`. Without `allow-downloads`, Save and Export (browser
-  downloads) are blocked.
+  downloads) are blocked. With `?host=parent`, `allow-scripts allow-same-origin` is enough for
+  opening and saving (without `allow-same-origin` the frame's origin is `null` and there is no
+  bridge), and `allow-downloads` isn't needed.
 - Don't send `X-Frame-Options: DENY` or a `frame-ancestors` CSP that excludes the embedding page.
 
+## Opening and saving through the page (`?host=parent`)
+
+A page that keeps the files itself (a Nextcloud app, a file server) can frame DeckCraft with
+`?host=parent` on the iframe `src`, hand it a presentation and take back what it saves, instead of
+the user downloading. GridCraft, WordCraft and PdfCraft have the same bridge with their own prefix.
+The page and DeckCraft must be on the **same origin**: DeckCraft only hears and answers its parent
+window on its own origin, and without one it downloads as usual.
+
+Messages are plain objects with a `type`:
+
+| Message | Direction | Fields |
+|---|---|---|
+| `deckcraft:ready` | to the page | `version`. The app runs and listens: send the file now. |
+| `deckcraft:open` | from the page | `name` (a bare file name, such as `Talk.pptx`), `bytes` (`ArrayBuffer` or `Uint8Array`). Opens like File › Open: a presentation (.pptx, .potx, .ppsx, .deckcraft) has that name as its file; an outline (.txt, .md, .rtf), a file sent without a name and a damaged file open untitled. |
+| `deckcraft:save` | to the page | `name`, `saveAs`, `bytes` (a transferred `ArrayBuffer`), for every file DeckCraft would otherwise download. The page stores it. |
+| `deckcraft:dirty` | to the page | `dirty`, whenever unsaved changes appear or go away. |
+| `deckcraft:failed` | to the page | `error`, when the app couldn't start (no WebGPU or WebGL2). |
+
+`saveAs` says whether the file becomes the presentation's file, as on the desktop:
+
+- **Save** sends the file the page sent, under its own name and format (`Talk.pptx` comes back
+  as `Talk.pptx`), with `saveAs: false`. DeckCraft keeps only the part after the last `/`, so
+  `docs/Talk.pptx` also comes back as `Talk.pptx`. A presentation that has no file the page sent
+  (a new one, an outline, a file sent without a name, a file the user dropped, a repaired copy of
+  a damaged file) is a new file with `saveAs: true`: Ctrl+S names it `<title>.deckcraft` as Save
+  suggests on the desktop, and File › Save opens the Save As page first, as on the desktop.
+- **Save As** (.pptx or .deckcraft) sends `saveAs: true`. The presentation is now that file; the
+  next Save sends its name with `saveAs: false`.
+- **Exports and Print** (PDF, handouts, pictures, outline, GIF) send `saveAs: false` and are
+  copies: the presentation keeps its file and its unsaved changes.
+
+`saveAs: false` doesn't mean "safe to overwrite": an export is `false` under a name the page may
+already hold (`Talk.pdf`, or `Talk.pptx` exported from a presentation that is now
+`Talk.deckcraft`). Replace a file without asking only when the name is the one the page sent, or
+the name of the last `saveAs: true` file it stored for this presentation; ask for anything else.
+DeckCraft doesn't learn the name the page finally stores a Save As under, so a page that renames
+on a conflict should map later Saves of the old name itself.
+
+In host mode DeckCraft starts with an empty presentation instead of the sample, and the first
+presentation the page sends takes its place unless the user has changed it; later ones open
+beside it. The page guards leaving itself (DeckCraft adds no guard of its own), and
+`&author=Name` signs the user's comments.
+
+```html
+<iframe id="deck" src="/deckcraft/?host=parent&author=Ada" style="width: 100%; height: 720px; border: 0;"></iframe>
+<script>
+  const frame = document.getElementById("deck");
+  addEventListener("message", async (e) => {
+    if (e.origin !== location.origin || e.source !== frame.contentWindow) return;
+    if (e.data.type === "deckcraft:ready") {
+      const bytes = await (await fetch("/files/Talk.pptx")).arrayBuffer();
+      frame.contentWindow.postMessage({ type: "deckcraft:open", name: "Talk.pptx", bytes }, location.origin, [bytes]);
+    } else if (e.data.type === "deckcraft:save") {
+      // Store e.data.bytes as e.data.name. Replace silently only when !e.data.saveAs and the name
+      // is the one sent (or the last saveAs file stored); ask before replacing anything else.
+    }
+  });
+</script>
+```
+
 ## Renderer selection and fallback flags
 
 DeckCraft renders with wgpu. It uses **WebGPU** when the browser has it and falls back to
@@ -82,6 +145,7 @@ DeckCraft renders with wgpu. It uses **WebGPU** when the browser has it and fall
 | `?webgl` | Force the WebGL2 backend (useful when a WebGPU driver misbehaves) |
 | `?blank` | Start with an empty presentation instead of the sample deck |
 | `?show` | Start the slide show immediately (kiosk/embedded decks) |
+| `?host=parent` | Open and save through the framing page ([above](#opening-and-saving-through-the-page-hostparent)); `&author=` names the user |
 
 For example: `<iframe src="https://example.com/deckcraft/?webgl" ...>`.
 

xtask/src/stats.rs

@@ -18,7 +18,13 @@ fn walk(dir: &Path, c: &mut Counts) {
         let p = e.path();
         let name = e.file_name();
         let name = name.to_string_lossy();
-        if p.is_dir() {
+        // `file_type` does not follow links, so a directory link is not walked (and aliases are
+        // not counted twice).
+        let Ok(kind) = e.file_type() else { continue };
+        if kind.is_symlink() {
+            continue;
+        }
+        if kind.is_dir() {
             // Nested fuzz workspaces and build output are not part of the crate.
             if name != "target" && name != "fuzz" && !name.starts_with('.') {
                 walk(&p, c);