Export: a progress dialog with Cancel for background exports

While an export runs in the background (Background Export), a dialog shows
what is being exported and how far it has got: artboard by artboard for a
raster export of several artboards, busy otherwise. Cancel (also Esc) stops
it and writes no file; Continue in Background leaves it to the status bar.
It opens after 0.4 s and never over another dialog.

Built on the shared vectorcraft_doc::cancel (#2546): fileio::progress::Progress
wraps its CancelToken and a progress sink, so a cancelled export stops
drawing and keeps no half-drawn pattern tile or effect raster.

- ui: background jobs carry their Progress; export_progress draws the
  dialog; UI commands file.cancelExport and file.exportInBackground.
- i18n: the strings in every language with complete menus, Danish, Dutch
  and Indonesian included; "{n} more exports waiting" is a plural (trn).
- docs: ui-parity, gaps (G12) and ROADMAP rows.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Dt49z1ubK9x1bPq51APgz3

crates/engine/src/cmd/fileio/mod.rs

@@ -40,6 +40,7 @@ pub mod pdf;
 mod pdfimport;
 pub mod pngtext;
 pub mod ppi;
+pub mod progress;
 pub mod psdread;
 mod save;
 mod screens;

crates/engine/src/cmd/fileio/progress.rs

@@ -0,0 +1,82 @@
+//! Progress and Cancel of an export running off the UI thread (Background Export), on the shared
+//! [`vectorcraft_doc::cancel`] mechanism.
+//!
+//! The frontend makes a [`Progress`], runs the export inside [`scope`] on its worker and reads the
+//! counts from the UI thread to draw them; its Cancel button calls [`Progress::cancel`]. Inside the
+//! scope the encoders that work in steps (raster formats: one artboard at a time) report each step
+//! through [`vectorcraft_doc::cancel::progress`] and stop at the next check once cancelled; the
+//! renderer stops drawing and keeps no half-drawn pattern tile or effect raster. Encoders that
+//! make one file in one go report nothing: the frontend shows them as busy and checks
+//! [`Progress::cancelled`] itself before writing, so a cancelled export never writes a file.
+
+use std::rc::Rc;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicU64, Ordering};
+
+use vectorcraft_doc::cancel::{self, CancelToken, ProgressSink};
+
+/// How far an export has got, shared between the worker and the UI thread.
+#[derive(Debug, Default)]
+pub struct Progress {
+    token: CancelToken,
+    done: AtomicU64,
+    total: AtomicU64,
+}
+
+impl Progress {
+    pub fn new() -> Arc<Self> {
+        Arc::new(Self::default())
+    }
+
+    /// `(steps done, steps in all)`; `total` is 0 while the export can't say (one file made in one go).
+    pub fn counts(&self) -> (u64, u64) {
+        let total = self.total.load(Ordering::Relaxed);
+        (self.done.load(Ordering::Relaxed).min(total), total)
+    }
+
+    /// The share of the export done, 0 to 1; `None` while the export can't say.
+    pub fn fraction(&self) -> Option<f64> {
+        let (done, total) = self.counts();
+        (total > 0).then(|| done as f64 / total as f64)
+    }
+
+    /// Ask the export to stop: it writes nothing more, and a render under way stops drawing.
+    pub fn cancel(&self) {
+        self.token.cancel();
+    }
+
+    pub fn cancelled(&self) -> bool {
+        self.token.is_cancelled()
+    }
+}
+
+/// Run `f` with `progress`'s token in effect on this thread and the steps reported to it.
+pub fn scope<R>(progress: &Arc<Progress>, f: impl FnOnce() -> R) -> R {
+    let to = Arc::clone(progress);
+    let sink: ProgressSink = Rc::new(move |done, total, _| {
+        to.total.store(total, Ordering::Relaxed);
+        to.done.store(done, Ordering::Relaxed);
+    });
+    cancel::scope(&progress.token, Some(sink), f)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn a_raster_export_counts_its_artboards_and_stops_once_cancelled() {
+        let mut doc = vectorcraft_doc::Document::new(100.0, 100.0);
+        let second = doc.artboards[0].clone();
+        doc.artboards.push(second);
+        let p = Progress::new();
+        assert_eq!(p.fraction(), None, "nothing reported yet");
+        let png = scope(&p, || super::super::encode_all(&doc, "png", &serde_json::json!({"useArtboards": true})));
+        assert!(png.is_ok(), "{:?}", png.err());
+        assert_eq!(p.counts(), (1, 2), "the step under way when the last artboard started");
+        p.cancel();
+        let r = scope(&p, || super::super::encode_all(&doc, "png", &serde_json::json!({"useArtboards": true})));
+        assert!(matches!(r, Err(crate::EngineError::Cancelled)), "{:?}", r.err());
+        assert!(!cancel::is_cancelled(), "the scope ended");
+    }
+}

crates/ui-egui/src/background.rs

@@ -6,9 +6,11 @@
 //! It needs a thread-safe writer from the host ([`crate::Services::write_shared`], desktop);
 //! without one (the web, which downloads) the work runs at once, as with the preference off.
 
+use std::sync::Arc;
 use std::sync::mpsc::{Receiver, Sender, channel};
 
 use serde_json::{Value, json};
+use vectorcraft_engine::cmd::fileio::progress::Progress;
 use vectorcraft_engine::file_access::ScopeHandle;
 
 use crate::VectorcraftApp;
@@ -50,9 +52,24 @@ pub struct Job {
     pub label: String,
     /// The document the job reads (`DocState::uid`), if any.
     pub doc: Option<u64>,
+    /// How far an export has got, and its Cancel ([`crate::export_progress`] shows it).
+    pub progress: Option<Arc<Progress>>,
+    /// Continue in Background: the progress dialog no longer shows this job.
+    pub hidden: bool,
     then: Then,
 }
 
+impl Job {
+    pub fn id(&self) -> u64 {
+        self.id
+    }
+
+    /// Was the job cancelled (it writes nothing more; its result is still on its way)?
+    pub fn cancelled(&self) -> bool {
+        self.progress.as_ref().is_some_and(|p| p.cancelled())
+    }
+}
+
 /// The worker and the jobs it has not finished.
 #[derive(Default)]
 pub struct Background {
@@ -93,6 +110,26 @@ impl Background {
     pub fn busy_with(&self, uid: u64) -> bool {
         self.jobs.iter().any(|j| j.doc == Some(uid))
     }
+
+    /// Cancel every export in progress → how many there were.
+    pub fn cancel_exports(&mut self) -> usize {
+        let mut n = 0;
+        for p in self.jobs.iter().filter(|j| !j.cancelled()).filter_map(|j| j.progress.as_ref()) {
+            p.cancel();
+            n += 1;
+        }
+        n
+    }
+
+    /// Hide the exports in progress from the progress dialog (they go on) → how many there were.
+    pub fn hide_exports(&mut self) -> usize {
+        let mut n = 0;
+        for j in self.jobs.iter_mut().filter(|j| j.progress.is_some() && !j.hidden && !j.cancelled()) {
+            j.hidden = true;
+            n += 1;
+        }
+        n
+    }
 }
 
 /// Run `work` on a worker thread when `enabled` and the host can write from one, else now; `then`
@@ -106,6 +143,20 @@ pub fn run(
     doc: Option<u64>,
     work: impl FnOnce(Writer) -> Result<Value, String> + Send + 'static,
     then: impl FnOnce(&mut VectorcraftApp, Result<Value, String>) -> Result<Value, String> + 'static,
+) -> Result<Value, String> {
+    run_with_progress(app, enabled, label, doc, None, work, then)
+}
+
+/// [`run`] for work that reports to `progress` (an export): the progress dialog shows it while it
+/// runs in the background, with Cancel.
+pub fn run_with_progress(
+    app: &mut VectorcraftApp,
+    enabled: bool,
+    label: String,
+    doc: Option<u64>,
+    progress: Option<Arc<Progress>>,
+    work: impl FnOnce(Writer) -> Result<Value, String> + Send + 'static,
+    then: impl FnOnce(&mut VectorcraftApp, Result<Value, String>) -> Result<Value, String> + 'static,
 ) -> Result<Value, String> {
     let mut work: Work = Box::new(work);
     let shared = app.services.write_shared.clone().filter(|_| enabled && app.services.download.is_none());
@@ -116,7 +167,7 @@ pub fn run(
                 Ok(()) => {
                     let bg = &mut app.background;
                     bg.next_id += 1;
-                    bg.jobs.push(Job { id, label: label.clone(), doc, then: Box::new(then) });
+                    bg.jobs.push(Job { id, label: label.clone(), doc, progress, hidden: false, then: Box::new(then) });
                     if label.is_empty() {
                         return Ok(json!({ "background": true }));
                     }

crates/ui-egui/src/chrome.rs

@@ -739,7 +739,7 @@ pub fn status_bar(app: &mut VectorcraftApp, ui: &mut Ui) {
                         .background
                         .jobs
                         .iter()
-                        .filter(|j| !j.label.is_empty())
+                        .filter(|j| !j.label.is_empty() && !j.cancelled())
                         .map(|j| j.label.as_str())
                         .chain(app.opening.pending.iter().map(|p| p.label.as_str()))
                         .collect();

crates/ui-egui/src/export_progress.rs

@@ -0,0 +1,196 @@
+//! The export progress dialog: while an export runs in the background (Background Export) a modal
+//! window shows what is being exported, how far it has got (artboard by artboard for raster
+//! exports of several artboards; busy for one artboard and for formats made in one go, which
+//! report no steps) and two buttons: Cancel (`file.cancelExport`, also
+//! Esc) stops it and writes nothing, Continue in Background (`file.exportInBackground`) closes the
+//! dialog and leaves the export to the status bar.
+//!
+//! It opens after [`DELAY`] so a quick export doesn't flash it, and waits while another dialog is
+//! open (the overwrite question, an options dialog): never two modals at once.
+
+use serde_json::json;
+
+use crate::dialogs::modal;
+use crate::theme::Tokens;
+use crate::{VectorcraftApp, widgets};
+
+/// Seconds an export runs before the dialog opens.
+pub const DELAY: f64 = 0.4;
+
+/// Where the job a frame first saw is remembered (its id, the time it was first seen).
+fn seen_id() -> egui::Id {
+    egui::Id::new("export-progress-seen")
+}
+
+/// What the dialog shows: (label, steps done, steps in all, share done, exports after this one).
+fn shown(app: &VectorcraftApp, now: f64, ctx: &egui::Context) -> Option<(String, u64, u64, f32, usize)> {
+    let jobs: Vec<_> = app.background.jobs.iter().filter(|j| !j.hidden && !j.cancelled()).filter(|j| j.progress.is_some()).collect();
+    let first = jobs.first()?;
+    let since = ctx.data_mut(|m| {
+        let seen = m.get_temp_mut_or_insert_with(seen_id(), || (first.id(), now));
+        if seen.0 != first.id() {
+            *seen = (first.id(), now);
+        }
+        seen.1
+    });
+    if now - since < DELAY {
+        return None;
+    }
+    let (done, total) = first.progress.as_ref().map(|p| p.counts()).unwrap_or_default();
+    let frac = first.progress.as_ref().and_then(|p| p.fraction()).unwrap_or(0.0) as f32;
+    Some((first.label.clone(), done, total, frac, jobs.len() - 1))
+}
+
+pub fn show(app: &mut VectorcraftApp, ctx: &egui::Context) {
+    let now = ctx.input(|i| i.time);
+    let Some((label, done, total, frac, more)) = shown(app, now, ctx) else { return };
+    if app.ui.dialog.is_some() {
+        return;
+    }
+    let t = Tokens::get(ctx);
+    let heading = format!("{}…", crate::i18n::msg(&label));
+    let mut action = None;
+    modal::show(ctx, &heading, egui::Id::new("export-progress"), -40.0, 20, |ui| {
+        ui.set_width(360.0);
+        modal::heading(ui, &heading);
+        ui.add_space(12.0);
+        // One step says nothing a spinner doesn't: the bar would sit at 0 % until the file is written.
+        if total > 1 {
+            let step = crate::i18n::fmt(tl!("Artboard {n} of {total}"), &[("n", &(done + 1).min(total).to_string()), ("total", &total.to_string())]);
+            // The count on its own line: drawn over the bar it would straddle the fill's edge.
+            ui.horizontal(|ui| {
+                ui.label(egui::RichText::new(step).color(t.text_dim));
+                ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
+                    ui.label(egui::RichText::new(format!("{:.0} %", frac * 100.0)).color(t.text_dim));
+                });
+            });
+            ui.add_space(4.0);
+            ui.add(egui::ProgressBar::new(frac).desired_width(360.0).desired_height(6.0).fill(t.accent));
+        } else {
+            ui.horizontal(|ui| {
+                ui.add(egui::Spinner::new().size(14.0).color(t.accent));
+                ui.label(egui::RichText::new(tl!("Encoding and writing the file…")).color(t.text_dim));
+            });
+        }
+        if more > 0 {
+            ui.add_space(6.0);
+            let queued = crate::i18n::tn(more as u64, "{n} more export waiting", "{n} more exports waiting");
+            ui.label(egui::RichText::new(queued).size(11.5).color(t.text_dim));
+        }
+        ui.add_space(16.0);
+        let row = egui::vec2(ui.min_rect().width(), ui.spacing().interact_size.y);
+        ui.allocate_ui_with_layout(row, egui::Layout::right_to_left(egui::Align::Center), |ui| {
+            if widgets::secondary_button(ui, "Cancel").clicked() {
+                action = Some("file.cancelExport");
+            }
+            ui.add_space(8.0);
+            if widgets::secondary_button(ui, "Continue in Background").clicked() {
+                action = Some("file.exportInBackground");
+            }
+        });
+    });
+    if ctx.input(|i| i.key_pressed(egui::Key::Escape)) {
+        action = Some("file.cancelExport");
+    }
+    if let Some(id) = action
+        && let Err(e) = app.run(id, json!({}))
+    {
+        app.status(e);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::sync::Arc;
+
+    use serde_json::json;
+    use vectorcraft_engine::Session;
+    use vectorcraft_engine::cmd::fileio::progress::Progress;
+
+    use crate::{Services, VectorcraftApp, background};
+
+    /// An app whose background writer waits until `go` is set.
+    fn app(go: Arc<std::sync::atomic::AtomicBool>) -> VectorcraftApp {
+        let services = Services {
+            write_shared: Some(Arc::new(move |_: &str, _: &[u8]| {
+                while !go.load(std::sync::atomic::Ordering::SeqCst) {
+                    std::thread::sleep(std::time::Duration::from_millis(1));
+                }
+                Ok(())
+            })),
+            ..Default::default()
+        };
+        VectorcraftApp::new(Session::new(), services)
+    }
+
+    /// Draws one frame of the dialog at `time` seconds → the texts it drew.
+    fn frame(app: &mut VectorcraftApp, ctx: &egui::Context, time: f64) -> String {
+        let mut out = ctx.run_ui(egui::RawInput { time: Some(time), ..Default::default() }, |ui| super::show(app, ui.ctx()));
+        out.textures_delta.clear();
+        let mut texts = String::new();
+        for shape in out.shapes {
+            if let egui::epaint::Shape::Text(t) = shape.shape {
+                texts.push_str(t.galley.text());
+                texts.push('\n');
+            }
+        }
+        texts
+    }
+
+    #[test]
+    fn opens_after_the_delay_and_cancel_closes_it() {
+        let go = Arc::new(std::sync::atomic::AtomicBool::new(false));
+        let mut app = app(go.clone());
+        let p = Progress::new();
+        let r = background::run_with_progress(
+            &mut app,
+            true,
+            "Exporting a.png".into(),
+            None,
+            Some(p.clone()),
+            |w| w("/a.png", b"x").map(|()| json!({})),
+            |_, r| r,
+        );
+        assert_eq!(r.unwrap()["background"], true);
+        let ctx = egui::Context::default();
+        crate::theme::install_fonts(&ctx);
+        assert!(!frame(&mut app, &ctx, 0.0).contains("Exporting a.png"), "not before the delay");
+        frame(&mut app, &ctx, 1.0); // a new window measures itself unseen first
+        let shown = frame(&mut app, &ctx, 1.1);
+        assert!(shown.contains("Exporting a.png") && shown.contains("Cancel") && shown.contains("Continue in Background"), "{shown}");
+        app.run("file.cancelExport", json!({})).unwrap();
+        assert!(p.cancelled());
+        assert_eq!(app.ui.status, crate::io::EXPORT_CANCELLED);
+        assert!(!frame(&mut app, &ctx, 2.0).contains("Exporting a.png"), "a cancelled export isn't shown");
+        go.store(true, std::sync::atomic::Ordering::SeqCst);
+        background::wait_all(&mut app);
+    }
+
+    #[test]
+    fn continue_in_background_hides_it_and_the_export_goes_on() {
+        let go = Arc::new(std::sync::atomic::AtomicBool::new(false));
+        let mut app = app(go.clone());
+        let p = Progress::new();
+        background::run_with_progress(
+            &mut app,
+            true,
+            "Exporting b.png".into(),
+            None,
+            Some(p.clone()),
+            |w| w("/b.png", b"x").map(|()| json!({})),
+            |_, r| r,
+        )
+        .unwrap();
+        let ctx = egui::Context::default();
+        crate::theme::install_fonts(&ctx);
+        frame(&mut app, &ctx, 0.0);
+        frame(&mut app, &ctx, 1.0);
+        assert!(frame(&mut app, &ctx, 1.1).contains("Exporting b.png"));
+        assert_eq!(app.run("file.exportInBackground", json!({})).unwrap()["hidden"], 1);
+        assert!(!frame(&mut app, &ctx, 2.0).contains("Exporting b.png"));
+        assert!(!p.cancelled());
+        go.store(true, std::sync::atomic::Ordering::SeqCst);
+        background::wait_all(&mut app);
+        assert!(app.background.jobs.is_empty());
+    }
+}

crates/ui-egui/src/i18n/bg.tsv

@@ -5153,6 +5153,12 @@ theme	Appearance	Външен вид
 	Enable Guides for 9-Slice Scaling	Включване на водачи за 9-slice мащабиране
 	Persistent	Постоянна
 	Library Panel Options	Опции на панела с библиотека
+	Artboard {n} of {total}	Работна област {n} от {total}
+	Encoding and writing the file…	Кодиране и записване на файла…
+@plural	{n} more export waiting|{n} more exports waiting	Още {n} експортиране в изчакване|Още {n} експортирания в изчакване
+	Continue in Background	Продължаване във фонов режим
+	Cancel Export	Отказ от експортирането
+@msg	Export cancelled	Експортирането е отказано
 # Paragraph panel menu › Justification…
 	Desired	Желано
 	Word Spacing:	Разстояние между думите:

crates/ui-egui/src/i18n/cs.tsv

@@ -5188,6 +5188,12 @@ mark-style	Japanese	Japonské
 @msg	too many library panels were opened in this session	v této relaci bylo otevřeno příliš mnoho panelů knihoven
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Obraz má {_1} × {_2} pixelů, na jedné straně více než {LARGE_TRACE_SIDE}: vektorizuje se, ale pomaleji. Rychleji se vektorizuje s předvolbou nižší věrnosti nebo menší kopie obrazu.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Obraz byl vektorizován v rozlišení {_1} × {_2} pixelů, zmenšený z {_3} × {_4} (nejvýše {_5} megapixelů).
+	Artboard {n} of {total}	Pracovní plocha {n} z {total}
+	Encoding and writing the file…	Kódování a zápis souboru…
+@plural	{n} more export waiting|{n} more exports waiting	Čeká ještě {n} export|Čekají ještě {n} exporty|Čeká ještě {n} exportů
+	Continue in Background	Pokračovat na pozadí
+	Cancel Export	Zrušit export
+@msg	Export cancelled	Export byl zrušen
 # Paragraph panel menu › Justification…
 	Desired	Požadované
 	Word Spacing:	Mezery mezi slovy:

crates/ui-egui/src/i18n/da.tsv

@@ -5172,6 +5172,12 @@ swatch	Bright Violet	Kraftig violet
 	Typing	Indtastning
 	Persistent	Vedvarende
 	Library Panel Options	Indstillinger for bibliotekspanel
+	Artboard {n} of {total}	Tegneflade {n} af {total}
+	Encoding and writing the file…	Koder og skriver filen…
+@plural	{n} more export waiting|{n} more exports waiting	{n} eksport mere venter|{n} eksporter mere venter
+	Continue in Background	Fortsæt i baggrunden
+	Cancel Export	Annullér eksport
+@msg	Export cancelled	Eksport annulleret
 # Paragraph panel menu › Justification…
 	Desired	Ønsket
 	Word Spacing:	Ordafstand:

crates/ui-egui/src/i18n/de.tsv

@@ -4763,6 +4763,12 @@ effect	Regular	Regelmäßig
 @msg	too many library panels were opened in this session	in dieser Sitzung wurden zu viele Bibliotheksbedienfelder geöffnet
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Das Bild hat {_1} × {_2} Pixel, mehr als {LARGE_TRACE_SIDE} auf einer Seite: Es wird nachgezeichnet, aber langsamer. Eine Vorgabe mit geringerer Detailtreue oder eine kleinere Kopie des Bildes geht schneller.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Das Bild wurde mit {_1} × {_2} Pixeln nachgezeichnet, verkleinert von {_3} × {_4} (höchstens {_5} Megapixel).
+	Artboard {n} of {total}	Zeichenfläche {n} von {total}
+	Encoding and writing the file…	Datei wird codiert und geschrieben…
+@plural	{n} more export waiting|{n} more exports waiting	{n} weiterer Export wartet|{n} weitere Exporte warten
+	Continue in Background	Im Hintergrund fortsetzen
+	Cancel Export	Export abbrechen
+@msg	Export cancelled	Export abgebrochen
 # Paragraph panel menu › Justification…
 	Desired	Optimal
 	Word Spacing:	Wortabstand:

crates/ui-egui/src/i18n/el.tsv

@@ -5140,6 +5140,12 @@ effect	Points	Σημεία
 @msg	too many library panels were opened in this session	άνοιξαν πάρα πολλοί πίνακες βιβλιοθηκών σε αυτή τη συνεδρία
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Η εικόνα είναι {_1} × {_2} εικονοστοιχεία, πάνω από {LARGE_TRACE_SIDE} σε μία πλευρά: ανιχνεύεται, αλλά πιο αργά. Μια προρύθμιση χαμηλότερης πιστότητας ή ένα μικρότερο αντίγραφο της εικόνας ανιχνεύεται γρηγορότερα.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Η εικόνα ανιχνεύτηκε σε {_1} × {_2} εικονοστοιχεία, σμικρυμένη από {_3} × {_4} (το πολύ {_5} megapixel).
+	Artboard {n} of {total}	Πίνακας σχεδίασης {n} από {total}
+	Encoding and writing the file…	Κωδικοποίηση και εγγραφή του αρχείου…
+@plural	{n} more export waiting|{n} more exports waiting	{n} ακόμη εξαγωγή σε αναμονή|{n} ακόμη εξαγωγές σε αναμονή
+	Continue in Background	Συνέχεια στο παρασκήνιο
+	Cancel Export	Ακύρωση εξαγωγής
+@msg	Export cancelled	Η εξαγωγή ακυρώθηκε
 # Paragraph panel menu › Justification…
 	Desired	Επιθυμητό
 	Word Spacing:	Απόσταση λέξεων:

crates/ui-egui/src/i18n/es.tsv

@@ -5130,6 +5130,12 @@ mark-style	Japanese	Japonesas
 @msg	too many library panels were opened in this session	se abrieron demasiados paneles de biblioteca en esta sesión
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	La imagen tiene {_1} × {_2} píxeles, más de {LARGE_TRACE_SIDE} en un lado: se calcará, pero más despacio. Un ajuste preestablecido de menor fidelidad o una copia más pequeña de la imagen se calcan más rápido.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	La imagen se calcó a {_1} × {_2} píxeles, reducida desde {_3} × {_4} ({_5} megapíxeles como máximo).
+	Artboard {n} of {total}	Mesa de trabajo {n} de {total}
+	Encoding and writing the file…	Codificando y escribiendo el archivo…
+@plural	{n} more export waiting|{n} more exports waiting	{n} exportación más en espera|{n} exportaciones más en espera
+	Continue in Background	Continuar en segundo plano
+	Cancel Export	Cancelar exportación
+@msg	Export cancelled	Exportación cancelada
 # Paragraph panel menu › Justification…
 	Desired	Deseado
 	Word Spacing:	Espaciado entre palabras:

crates/ui-egui/src/i18n/fi.tsv

@@ -5152,6 +5152,12 @@ mark-style	Japanese	Japanilainen
 @msg	too many library panels were opened in this session	tässä istunnossa on avattu liian monta kirjastopaneelia
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Kuva on {_1} × {_2} kuvapistettä, yhdeltä sivultaan yli {LARGE_TRACE_SIDE}: se jäljitetään, mutta hitaammin. Pienemmän tarkkuuden esiasetus tai kuvan pienempi kopio jäljittyy nopeammin.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Kuva jäljitettiin kokoon {_1} × {_2} kuvapistettä pienennettynä koosta {_3} × {_4} (enintään {_5} megapikseliä).
+	Artboard {n} of {total}	Piirtoalusta {n}/{total}
+	Encoding and writing the file…	Tiedostoa koodataan ja kirjoitetaan…
+@plural	{n} more export waiting|{n} more exports waiting	{n} vienti odottaa|{n} vientiä odottaa
+	Continue in Background	Jatka taustalla
+	Cancel Export	Peruuta vienti
+@msg	Export cancelled	Vienti peruutettiin
 # Paragraph panel menu › Justification…
 	Desired	Haluttu
 	Word Spacing:	Sanaväli:

crates/ui-egui/src/i18n/fr.tsv

@@ -5187,6 +5187,12 @@ theme	Appearance	Apparence
 @msg	too many library panels were opened in this session	trop de panneaux de bibliothèque ont été ouverts dans cette session
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	L’image fait {_1} × {_2} pixels, plus de {LARGE_TRACE_SIDE} sur un côté : elle est vectorisée, mais plus lentement. Un paramètre prédéfini moins fidèle ou une copie plus petite de l’image se vectorise plus vite.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	L’image a été vectorisée à {_1} × {_2} pixels, réduite de {_3} × {_4} ({_5} mégapixels au plus).
+	Artboard {n} of {total}	Plan de travail {n} sur {total}
+	Encoding and writing the file…	Encodage et écriture du fichier…
+@plural	{n} more export waiting|{n} more exports waiting	{n} autre exportation en attente|{n} autres exportations en attente
+	Continue in Background	Continuer en arrière-plan
+	Cancel Export	Annuler l’exportation
+@msg	Export cancelled	Exportation annulée
 # Paragraph panel menu › Justification…
 	Desired	Optimal
 	Word Spacing:	Espacement des mots :

crates/ui-egui/src/i18n/hu.tsv

@@ -5174,6 +5174,12 @@ imageTrace	Outline	Körvonal
 @msg	too many library panels were opened in this session	ebben a munkamenetben túl sok könyvtárpanel nyílt meg
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	A kép {_1} × {_2} képpont, egyik oldalán több mint {LARGE_TRACE_SIDE}: a vektorizálás megtörténik, de lassabban. Kisebb hűségű előbeállítással vagy a kép kisebb másolatával gyorsabb.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	A kép vektorizálása {_1} × {_2} képponton történt, {_3} × {_4} méretről kicsinyítve (legfeljebb {_5} megapixel).
+	Artboard {n} of {total}	Rajztábla: {n} / {total}
+	Encoding and writing the file…	A fájl kódolása és írása…
+@plural	{n} more export waiting|{n} more exports waiting	Még {n} exportálás várakozik
+	Continue in Background	Folytatás a háttérben
+	Cancel Export	Exportálás megszakítása
+@msg	Export cancelled	Az exportálás megszakítva
 # Paragraph panel menu › Justification…
 	Desired	Kívánt
 	Word Spacing:	Szóköz:

crates/ui-egui/src/i18n/id.tsv

@@ -5172,6 +5172,12 @@ swatch	Bright Violet	Violet cerah
 	Typing	Mengetik
 	Persistent	Persisten
 	Library Panel Options	Opsi panel pustaka
+	Artboard {n} of {total}	Artboard {n} dari {total}
+	Encoding and writing the file…	Mengodekan dan menulis berkas…
+@plural	{n} more export waiting|{n} more exports waiting	{n} ekspor lagi menunggu
+	Continue in Background	Lanjutkan di latar belakang
+	Cancel Export	Batalkan ekspor
+@msg	Export cancelled	Ekspor dibatalkan
 # Paragraph panel menu › Justification…
 	Desired	Diinginkan
 	Word Spacing:	Spasi Kata:

crates/ui-egui/src/i18n/it.tsv

@@ -4801,6 +4801,12 @@ lighting	Light	Luce
 @msg	too many library panels were opened in this session	in questa sessione sono stati aperti troppi pannelli libreria
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	L’immagine è di {_1} × {_2} pixel, più di {LARGE_TRACE_SIDE} su un lato: viene vettorializzata, ma più lentamente. Un predefinito a fedeltà più bassa o una copia più piccola dell’immagine è più veloce.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	L’immagine è stata vettorializzata a {_1} × {_2} pixel, ridotta da {_3} × {_4} (al massimo {_5} megapixel).
+	Artboard {n} of {total}	Tavola da disegno {n} di {total}
+	Encoding and writing the file…	Codifica e scrittura del file…
+@plural	{n} more export waiting|{n} more exports waiting	{n} altra esportazione in attesa|{n} altre esportazioni in attesa
+	Continue in Background	Continua in background
+	Cancel Export	Annulla esportazione
+@msg	Export cancelled	Esportazione annullata
 # Paragraph panel menu › Justification…
 	Desired	Desiderato
 	Word Spacing:	Spaziatura parole:

crates/ui-egui/src/i18n/ja.tsv

@@ -4841,6 +4841,12 @@ lighting	Light	ライト
 @msg	too many library panels were opened in this session	このセッションで開いたライブラリパネルが多すぎます
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	画像は {_1} × {_2} ピクセルで、一辺が {LARGE_TRACE_SIDE} を超えています。トレースはできますが、時間がかかります。忠実度の低いプリセットや画像の小さいコピーを使うと速くなります。
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	画像は {_3} × {_4} から縮小した {_1} × {_2} ピクセルでトレースされました (最大 {_5} メガピクセル)。
+	Artboard {n} of {total}	アートボード {n} / {total}
+	Encoding and writing the file…	ファイルをエンコードして書き込み中…
+@plural	{n} more export waiting|{n} more exports waiting	待機中の書き出し: あと {n} 件
+	Continue in Background	バックグラウンドで続行
+	Cancel Export	書き出しをキャンセル
+@msg	Export cancelled	書き出しをキャンセルしました
 # Paragraph panel menu › Justification…
 	Desired	最適
 	Word Spacing:	単語間隔:

crates/ui-egui/src/i18n/ko.tsv

@@ -4764,6 +4764,12 @@ lighting	Light	광원
 @msg	too many library panels were opened in this session	이 세션에서 라이브러리 패널을 너무 많이 열었습니다
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	이미지가 {_1} × {_2}픽셀로 한 변이 {LARGE_TRACE_SIDE}을 넘습니다. 추적은 되지만 더 느립니다. 충실도가 낮은 사전 설정이나 이미지의 작은 사본을 사용하면 더 빠릅니다.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	이미지를 {_3} × {_4}에서 축소한 {_1} × {_2}픽셀로 추적했습니다(최대 {_5}메가픽셀).
+	Artboard {n} of {total}	아트보드 {n} / {total}
+	Encoding and writing the file…	파일을 인코딩하고 쓰는 중…
+@plural	{n} more export waiting|{n} more exports waiting	대기 중인 내보내기 {n}개 더
+	Continue in Background	백그라운드에서 계속
+	Cancel Export	내보내기 취소
+@msg	Export cancelled	내보내기를 취소했습니다
 # Paragraph panel menu › Justification…
 	Desired	희망
 	Word Spacing:	단어 간격:

crates/ui-egui/src/i18n/nl.tsv

@@ -5215,7 +5215,12 @@ swatch	Bright Violet	Felviolet
 @msg	too many library panels were opened in this session	er zijn in deze sessie te veel bibliotheekpanelen geopend
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	De afbeelding is {_1} × {_2} pixels, meer dan {LARGE_TRACE_SIDE} aan één zijde: ze wordt getraceerd, maar langzamer. Een voorinstelling met minder detail of een kleinere kopie van de afbeelding traceert sneller.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	De afbeelding is getraceerd op {_1} × {_2} pixels, verkleind van {_3} × {_4} (maximaal {_5} megapixels).
-
+	Artboard {n} of {total}	Tekengebied {n} van {total}
+	Encoding and writing the file…	Bestand coderen en schrijven…
+@plural	{n} more export waiting|{n} more exports waiting	Nog {n} export in de wachtrij|Nog {n} exports in de wachtrij
+	Continue in Background	Doorgaan op achtergrond
+	Cancel Export	Export annuleren
+@msg	Export cancelled	Export geannuleerd
 # Paragraph panel menu › Justification…
 	Desired	Gewenst
 	Word Spacing:	Woordafstand:

crates/ui-egui/src/i18n/pl.tsv

@@ -5040,6 +5040,12 @@ mark-style	Japanese	Japońskie
 @msg	too many library panels were opened in this session	w tej sesji otwarto zbyt wiele paneli bibliotek
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Obraz ma {_1} × {_2} pikseli, ponad {LARGE_TRACE_SIDE} na jednym boku: zostanie obrysowany, ale wolniej. Ustawienie wstępne o niższej wierności lub mniejsza kopia obrazu obrysuje się szybciej.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Obraz obrysowano w rozdzielczości {_1} × {_2} pikseli, po zmniejszeniu z {_3} × {_4} (najwyżej {_5} megapikseli).
+	Artboard {n} of {total}	Obszar kompozycji {n} z {total}
+	Encoding and writing the file…	Kodowanie i zapisywanie pliku…
+@plural	{n} more export waiting|{n} more exports waiting	Czeka jeszcze {n} eksport|Czekają jeszcze {n} eksporty|Czeka jeszcze {n} eksportów
+	Continue in Background	Kontynuuj w tle
+	Cancel Export	Anuluj eksport
+@msg	Export cancelled	Eksport anulowany
 # Paragraph panel menu › Justification…
 	Desired	Optymalne
 	Word Spacing:	Odstępy między wyrazami:

crates/ui-egui/src/i18n/pt-br.tsv

@@ -5105,6 +5105,12 @@ mark-style	Japanese	Japonesas
 @msg	too many library panels were opened in this session	foram abertos painéis de biblioteca demais nesta sessão
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	A imagem tem {_1} × {_2} pixels, mais de {LARGE_TRACE_SIDE} em um lado: ela é traçada, mas mais devagar. Uma predefinição de menor fidelidade ou uma cópia menor da imagem traça mais rápido.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	A imagem foi traçada em {_1} × {_2} pixels, reduzida de {_3} × {_4} (no máximo {_5} megapixels).
+	Artboard {n} of {total}	Mesa de Trabalho {n} de {total}
+	Encoding and writing the file…	Codificando e gravando o arquivo…
+@plural	{n} more export waiting|{n} more exports waiting	Mais {n} exportação aguardando|Mais {n} exportações aguardando
+	Continue in Background	Continuar em Segundo Plano
+	Cancel Export	Cancelar Exportação
+@msg	Export cancelled	Exportação cancelada
 # Paragraph panel menu › Justification…
 	Desired	Desejado
 	Word Spacing:	Espaçamento entre Palavras:

crates/ui-egui/src/i18n/ru.tsv

@@ -4797,6 +4797,12 @@ lighting	Light	Свет
 @msg	too many library panels were opened in this session	в этом сеансе открыто слишком много панелей библиотек
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Изображение {_1} × {_2} пикселей, больше {LARGE_TRACE_SIDE} по одной стороне: трассировка выполняется, но медленнее. Стиль с меньшей точностью или уменьшенная копия изображения трассируются быстрее.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Изображение трассировано в размере {_1} × {_2} пикселей, уменьшенное с {_3} × {_4} (не более {_5} мегапикселей).
+	Artboard {n} of {total}	Монтажная область {n} из {total}
+	Encoding and writing the file…	Кодирование и запись файла…
+@plural	{n} more export waiting|{n} more exports waiting	Ещё {n} экспорт в очереди|Ещё {n} экспорта в очереди|Ещё {n} экспортов в очереди
+	Continue in Background	Продолжить в фоне
+	Cancel Export	Отменить экспорт
+@msg	Export cancelled	Экспорт отменён
 # Paragraph panel menu › Justification…
 	Desired	Желательно
 	Word Spacing:	Интервал между словами:

crates/ui-egui/src/i18n/sv.tsv

@@ -5144,6 +5144,12 @@ theme	Appearance	Utseende
 @msg	too many library panels were opened in this session	för många bibliotekspaneler har öppnats i den här sessionen
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Bilden är {_1} × {_2} pixlar, mer än {LARGE_TRACE_SIDE} på en sida: den vektoriseras, men långsammare. En förinställning med lägre återgivning eller en mindre kopia av bilden går snabbare.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Bilden vektoriserades vid {_1} × {_2} pixlar, nedskalad från {_3} × {_4} (högst {_5} megapixlar).
+	Artboard {n} of {total}	Rityta {n} av {total}
+	Encoding and writing the file…	Kodar och skriver filen…
+@plural	{n} more export waiting|{n} more exports waiting	{n} export till väntar|{n} exporter till väntar
+	Continue in Background	Fortsätt i bakgrunden
+	Cancel Export	Avbryt export
+@msg	Export cancelled	Exporten avbröts
 # Paragraph panel menu › Justification…
 	Desired	Önskat
 	Word Spacing:	Ordavstånd:

crates/ui-egui/src/i18n/uk.tsv

@@ -4781,6 +4781,12 @@ lighting	Light	Світло
 @msg	too many library panels were opened in this session	у цьому сеансі відкрито забагато панелей бібліотек
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Зображення {_1} × {_2} пікселів, понад {LARGE_TRACE_SIDE} з одного боку: трасування виконується, але повільніше. Стиль із нижчою точністю або менша копія зображення трасуються швидше.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Зображення трасовано в розмірі {_1} × {_2} пікселів, зменшене з {_3} × {_4} (щонайбільше {_5} мегапікселів).
+	Artboard {n} of {total}	Монтажна область {n} з {total}
+	Encoding and writing the file…	Кодування та запис файлу…
+@plural	{n} more export waiting|{n} more exports waiting	Ще {n} експорт в очікуванні|Ще {n} експорти в очікуванні|Ще {n} експортів в очікуванні
+	Continue in Background	Продовжити у фоні
+	Cancel Export	Скасувати експорт
+@msg	Export cancelled	Експорт скасовано
 # Paragraph panel menu › Justification…
 	Desired	Бажане
 	Word Spacing:	Інтервал між словами:

crates/ui-egui/src/i18n/vi.tsv

@@ -4781,6 +4781,12 @@ theme	Appearance	Giao diện
 @msg	too many library panels were opened in this session	đã mở quá nhiều bảng thư viện trong phiên này
 @msg	The image is {_1} × {_2} pixels, more than {LARGE_TRACE_SIDE} on a side: it is traced, but more slowly. A lower-fidelity preset or a smaller copy of the image traces faster.	Ảnh có kích thước {_1} × {_2} điểm ảnh, hơn {LARGE_TRACE_SIDE} ở một cạnh: ảnh vẫn được dò, nhưng chậm hơn. Một thiết lập sẵn có độ trung thực thấp hơn hoặc một bản sao nhỏ hơn của ảnh sẽ dò nhanh hơn.
 @msg	The image was traced at {_1} × {_2} pixels, scaled down from {_3} × {_4} ({_5} megapixels at most).	Ảnh đã được dò ở {_1} × {_2} điểm ảnh, thu nhỏ từ {_3} × {_4} (tối đa {_5} megapixel).
+	Artboard {n} of {total}	Bảng vẽ {n} / {total}
+	Encoding and writing the file…	Đang mã hóa và ghi tệp…
+@plural	{n} more export waiting|{n} more exports waiting	Còn {n} lượt xuất đang chờ
+	Continue in Background	Tiếp tục trong nền
+	Cancel Export	Hủy xuất
+@msg	Export cancelled	Đã hủy xuất
 # Paragraph panel menu › Justification…
 	Desired	Mong muốn
 	Word Spacing:	Khoảng cách từ:

crates/ui-egui/src/i18n/zh-hans.tsv

@@ -5023,7 +5023,12 @@ lighting	Light	光源
 @msg	only http, https and mailto URLs open in the browser, not “{url}”	浏览器中只会打开 http、https 和 mailto 的 URL，不会打开 “{url}”
 @msg	{id} opens another app: only the person at the keyboard can run it	{id} 会打开其他应用程序：只有使用键盘的人才能运行它
 @msg	“{name}” is not a file	“{name}” 不是文件
-
+	Artboard {n} of {total}	画板 {n} / {total}
+	Encoding and writing the file…	正在编码并写入文件…
+@plural	{n} more export waiting|{n} more exports waiting	另有 {n} 个导出等待中
+	Continue in Background	在后台继续
+	Cancel Export	取消导出
+@msg	Export cancelled	已取消导出
 # Paragraph panel menu › Justification…
 	Desired	所需
 	Word Spacing:	字间距：

crates/ui-egui/src/i18n/zh-hant.tsv

@@ -4077,6 +4077,12 @@ lighting	Light	光源
 	Enable Guides for 9-Slice Scaling	啟用 9-slice 縮放參考線
 	Persistent	持久
 	Library Panel Options	資料庫面板選項
+	Artboard {n} of {total}	工作區域 {n} / {total}
+	Encoding and writing the file…	正在編碼並寫入檔案…
+@plural	{n} more export waiting|{n} more exports waiting	另有 {n} 個匯出等待中
+	Continue in Background	在背景繼續
+	Cancel Export	取消匯出
+@msg	Export cancelled	已取消匯出
 # Paragraph panel menu › Justification…
 	Desired	所需
 	Word Spacing:	字間距：

crates/ui-egui/src/io.rs

@@ -3,7 +3,9 @@
 
 use serde_json::{Value, json};
 use vectorcraft_doc::SavedView;
+use vectorcraft_doc::cancel;
 use vectorcraft_engine::EngineError;
+use vectorcraft_engine::cmd::fileio::progress::{self, Progress};
 use vectorcraft_engine::cmd::fileio::{self, Format, SAVE_FORMATS, SaveMode, SavePlan, TEMPLATE_FORMATS};
 
 use crate::background::{self, Writer};
@@ -675,6 +677,25 @@ pub fn recent_files(app: &VectorcraftApp) -> &[String] {
     &r[..r.len().min(app.session.prefs.recent_files_count as usize)]
 }
 
+/// The status once an export was cancelled.
+pub const EXPORT_CANCELLED: &str = "Export cancelled";
+
+/// File → Cancel Export (the progress dialog's Cancel): every export running in the background
+/// stops and writes nothing more → `{cancelled: n}`.
+pub fn cancel_exports(app: &mut VectorcraftApp) -> Value {
+    let n = app.background.cancel_exports();
+    if n > 0 {
+        app.status(EXPORT_CANCELLED);
+    }
+    json!({ "cancelled": n })
+}
+
+/// The progress dialog's Continue in Background: the exports go on, shown in the status bar only
+/// → `{hidden: n}`.
+pub fn hide_exports(app: &mut VectorcraftApp) -> Value {
+    json!({ "hidden": app.background.hide_exports() })
+}
+
 /// Export the active document in `format` (default: the path's extension, else PNG) with the
 /// `document.export` options in `params` (artboard, range, useArtboards, selectedOnly, ppi, SVG
 /// options…): every file it writes (one per artboard, linked images) goes next to `path`. The
@@ -704,18 +725,31 @@ pub fn export(app: &mut VectorcraftApp, format: Option<&str>, path: Option<Strin
     // Background Export: encoded and written from this snapshot while editing goes on.
     let label = format!("Exporting {}", fileio::file_name(&path));
     let (params, target) = (params.clone(), path.clone());
+    // The progress dialog's counts and Cancel: a cancelled export stops drawing and never starts
+    // writing.
+    let progress = Progress::new();
+    let (reporting, asked) = (progress.clone(), progress.clone());
     let work = move |write: Writer| {
-        let enc = fileio::encode_all(&doc, f.id, &params).map_err(|e| e.to_string())?;
-        let files = write_encoded(write, &doc, &path, &enc)?;
-        let mut out = json!({ "path": files.first().unwrap_or(&path), "warnings": enc.warnings });
-        if files.len() > 1 {
-            out["files"] = json!(files);
-        }
-        Ok(out)
+        progress::scope(&reporting, || {
+            cancel::check().map_err(|e| e.to_string())?;
+            let enc = fileio::encode_all(&doc, f.id, &params).map_err(|e| e.to_string())?;
+            cancel::check().map_err(|e| e.to_string())?;
+            let files = write_encoded(write, &doc, &path, &enc)?;
+            let mut out = json!({ "path": files.first().unwrap_or(&path), "warnings": enc.warnings });
+            if files.len() > 1 {
+                out["files"] = json!(files);
+            }
+            Ok(out)
+        })
     };
     let enabled = app.session.prefs.background_export;
     let failed = target.clone();
-    let mut r = background::run(app, enabled, label, None, work, move |app, r| {
+    let mut r = background::run_with_progress(app, enabled, label, None, Some(progress), work, move |app, r| {
+        // A file written before the Cancel arrived is reported as written.
+        if r.is_err() && asked.cancelled() {
+            app.status(EXPORT_CANCELLED);
+            return Ok(json!({ "cancelled": true }));
+        }
         let r = r.inspect_err(|e| report_write_error(app, true, &failed, e))?;
         let what = match r["files"].as_array() {
             Some(files) => format!("{} files", files.len()),

crates/ui-egui/src/lib.rs

@@ -25,6 +25,7 @@ pub mod cursors;
 pub mod dialogs;
 pub mod dock;
 mod edit_toolbar;
+pub mod export_progress;
 pub mod find_font;
 pub mod floating;
 pub mod font_menu;
@@ -1440,6 +1441,7 @@ impl VectorcraftApp {
         dock::floating_panel(self, &ctx);
         floating::show(self, &ctx);
         dialogs::show(self, &ctx);
+        export_progress::show(self, &ctx);
         palette::show(self, &ctx);
         if self.custom_titlebar {
             titlebar::resize_zones(ui);

crates/ui-egui/src/menus.rs

@@ -747,6 +747,18 @@ pub const UI_COMMANDS: &[(&str, &str, &str, &str)] = &[
     ("file.openRecent29", "Open Recent File 29", "", "{}"),
     ("file.openRecent30", "Open Recent File 30", "", "{}"),
     ("file.reveal", "Show in Folder", "", "{} show the document's file in the system file manager (desktop) → {path}"),
+    (
+        "file.cancelExport",
+        "Cancel Export",
+        "",
+        "{} stop every export running in the background (Background Export): an export stops between artboards and writes no file once cancelled → {cancelled: n}",
+    ),
+    (
+        "file.exportInBackground",
+        "Continue in Background",
+        "",
+        "{} close the export progress dialog; the exports go on, shown in the status bar → {hidden: n}",
+    ),
     (
         "ui.dxfOptionsDialog",
         "DXF Options Dialog",
@@ -1101,6 +1113,8 @@ pub fn run_ui_command(app: &mut VectorcraftApp, id: &str, p: &Value) -> Option<R
         "file.newFromTemplate" if p.get("dataBase64").is_none() => io::new_from_template(app, s("path")),
         "file.revert" if p.get("confirmed").and_then(Value::as_bool) != Some(true) => io::ask_revert(app),
         "file.reveal" => io::reveal(app),
+        "file.cancelExport" => Ok(io::cancel_exports(app)),
+        "file.exportInBackground" => Ok(io::hide_exports(app)),
         id if id.starts_with("file.openRecent") => match recent_slot(app, id).cloned() {
             Some(path) => io::open_reporting(app, &path),
             None => Err("no such recent file".into()),
@@ -2225,6 +2239,7 @@ pub fn enabled(app: &VectorcraftApp, id: &str) -> bool {
         "type.bold" | "type.italic" => crate::panels::character::text_style(app).is_some(),
         id if crate::panels::paragraph::ALIGN_COMMANDS.iter().any(|c| c.0 == id) => crate::panels::character::text_style(app).is_some(),
         "file.reveal" => app.services.reveal.is_some() && app.session.active().is_some_and(|d| d.path.is_some()),
+        "file.cancelExport" | "file.exportInBackground" => app.background.jobs.iter().any(|j| j.progress.is_some() && !j.cancelled()),
         "file.place"
         | "file.export.svg"
         | "file.export.png"

crates/ui-egui/src/tests_background.rs

@@ -121,6 +121,34 @@ fn exports_run_in_the_background_and_the_preference_turns_both_off() {
     assert!(app.background.jobs.is_empty());
 }
 
+#[test]
+fn a_cancelled_export_writes_nothing() {
+    let (gate, writing) = (Gate::default(), Gate::default());
+    let files = Files::default();
+    let (f, g, w) = (files.clone(), gate.clone(), writing.clone());
+    let services = Services {
+        write_shared: Some(Arc::new(move |p: &str, b: &[u8]| {
+            w.open();
+            g.wait();
+            f.lock().unwrap().push((p.to_string(), b.to_vec()));
+            Ok(())
+        })),
+        ..Default::default()
+    };
+    let mut app = VectorcraftApp::new(Session::new(), services);
+    app.run("file.new", json!({"width": 100, "height": 100})).unwrap();
+    // The first export holds the worker at the gate, past its last check: it still writes.
+    io::export(&mut app, Some("svg"), Some("/out/first.svg".into()), &json!({})).unwrap();
+    writing.wait();
+    io::export(&mut app, Some("png"), Some("/out/second.png".into()), &json!({})).unwrap();
+    assert_eq!(app.run("file.cancelExport", json!({})).unwrap()["cancelled"], 2);
+    assert_eq!(app.run("file.cancelExport", json!({})).unwrap()["cancelled"], 0, "nothing left to cancel");
+    gate.open();
+    background::wait_all(&mut app);
+    assert_eq!(written(&files), ["/out/first.svg"]);
+    assert_eq!(app.ui.status, io::EXPORT_CANCELLED);
+}
+
 #[test]
 fn quitting_waits_for_background_saves() {
     let gate = Gate::default();