Merge pull request #1439 from Guillergood/codex/round-dash-dots

M4: draw dots for zero-length round dashes

ROADMAP.md

@@ -2,7 +2,7 @@
 
 **Stage: alpha** · next: beta, ~26 points and ~162–292 h away (one Opus 5.5 agent; ~33–67 h wall-clock with 5 agents)
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-28 · **Change:** minor (Arabic draft catalog; scaled instances keep their scale when their main is rebuilt (#922); .fig embedded images are copied once per blob, not once per hash (#1059); page ruler guides survive save and reopen (#1476); colour picker LCH and OKLCH models; non-ASCII layer names transliterate in code export (#1235); branches in live sessions and branch history entries, gap 17; plugin widgets take text input and a property menu (plugin API 4); boards: templates and tables; boards: a shared timer and voting sessions; boards: the dot grid, connector ends dragged to re-attach, curved connectors; Installed weights of an embedded font family (#1246); `.sketch` import, best effort (Sketch 48 and newer); CJK line breaking: JIS X 4051's line-start and line-end sets completed with the halfwidth small kana, the halfwidth and spacing (semi-)voiced sound marks, the iteration marks 〱–〵 and the halfwidth parentheses, with behaviour cases for each; Adobe Fonts found on macOS (#298); egui 0.37 hidden-capture deadline contract; Dev Mode measurements kept on the canvas and a read-only layers panel; boards: a board area row and progress entry; community fixes in #507, #510, #529 and #530: auto-save, a text box by dragging, batch step references, removing someone from a live session, Russian and Turkish catalogs reviewed, Czech and Indonesian drafts, the Japanese draft completed, zoom previews, the web clipboard, Alt-drag snapping and Cmd+D repeat, recovery copies, crash and rollback fixes, colour emoji, `.fig` import fixes; earlier changes are in the revision history below) · **Target:** Figma Design (desktop app 126.10.7)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-28 · **Change:** minor (M4: zero-length round-capped dashes draw dots; dash expansion uses the existing safety budget; extracted from #1143; Arabic draft catalog; scaled instances keep their scale when their main is rebuilt (#922); .fig embedded images are copied once per blob, not once per hash (#1059); page ruler guides survive save and reopen (#1476); colour picker LCH and OKLCH models; non-ASCII layer names transliterate in code export (#1235); branches in live sessions and branch history entries, gap 17; plugin widgets take text input and a property menu (plugin API 4); boards: templates and tables; boards: a shared timer and voting sessions; boards: the dot grid, connector ends dragged to re-attach, curved connectors; Installed weights of an embedded font family (#1246); `.sketch` import, best effort (Sketch 48 and newer); CJK line breaking: JIS X 4051's line-start and line-end sets completed with the halfwidth small kana, the halfwidth and spacing (semi-)voiced sound marks, the iteration marks 〱–〵 and the halfwidth parentheses, with behaviour cases for each; Adobe Fonts found on macOS (#298); egui 0.37 hidden-capture deadline contract; Dev Mode measurements kept on the canvas and a read-only layers panel; boards: a board area row and progress entry; community fixes in #507, #510, #529 and #530: auto-save, a text box by dragging, batch step references, removing someone from a live session, Russian and Turkish catalogs reviewed, Czech and Indonesian drafts, the Japanese draft completed, zoom previews, the web clipboard, Alt-drag snapping and Cmd+D repeat, recovery copies, crash and rollback fixes, colour emoji, `.fig` import fixes; earlier changes are in the revision history below) · **Target:** Figma Design (desktop app 126.10.7)
 
 FigCraft is a clean-room, open-source, pure-Rust reimplementation of the Figma design workflow,
 native on macOS, Windows, Linux and FreeBSD and in the browser, fully drivable by agents through
@@ -135,6 +135,7 @@ Ranked; detail and milestones in [`docs/roadmap.md`](docs/roadmap.md).
 - **2026-10-28** · M3, #922: an instance scaled with the Scale tool (or `transform.scale`) keeps its layers' scaled size and points when its main is rebuilt. The scaled layers' new size and place were read as what constraints give (an ancestor resized in the same edit), so no override was kept, and adding a layer to the main put a 14 px icon's 24 px triangle back. The Scale tool now records them as `size` and `position` overrides on layers inside instances; strokes already kept theirs. The report's own sequence (clearing effects on the component holding the icon) no longer reproduces on main. Regressions for a scaled instance, one scaled with the tool (with undo) and a scaled icon nested in a component and its instances. Numbers unchanged.
 - **2026-10-28** · M6, #1059: `.fig` import copies each image carried inside the message once per blob, shared by every hash that names it, instead of once per hash: a file pointing many hashes at one large blob no longer multiplies it in memory (100 hashes on a 250 MB blob were 25 GB). Regression test. Numbers unchanged.
 - **2026-10-28** · M1, #1476: page ruler guides survive save and reopen. A page kept its guides in the page kind while the layer's own `guides` field (frame guides, #70) took that key when a file was read, so a reopened page's guides vanished, and saving it wrote `guides` twice, which then refused to open. Every layer now keeps its guides in the one field, and a page with two `guides` lists opens with both. Regressions in the doc and format crates. Numbers unchanged.
+- **2026-10-27** · M4: zero-length round-capped dashes draw dots; dash expansion uses the existing safety budget; extracted from #1143. Numbers unchanged.
 - **2026-10-26** · Non-ASCII layer names transliterate in code export (M6, #1235): `class_name` runs the name through `deunicode` before its ASCII filter, so 로그인 화면 → `rogeuin-hwamyeon`, кнопка → `knopka`, über → `uber` in the HTML/CSS/React/Leptos class names, component roots and `data-*` variant attributes (SwiftUI/Compose type names unchanged); a name left with nothing (symbols only) takes the node's kind (`.text`, `.frame`) instead of `layer-`, and the 40-character cut lands on a word boundary. New dependency: deunicode (pure Rust tables, zero deps, BSD-3-Clause, the `slug` crate's base). `html_codegen_tests`. Numbers unchanged.
 - **2026-10-25** · egui 0.37 capture lifecycle: screenshots with hidden or unknown visibility queue, request a hidden paint, and expire after 60 seconds if no capture arrives (headless-tested contract). Logic-only edits, saves and inspection continue while hidden. Native visible GUI and forced hidden-window paint, browser and Wayland behavior remain unqualified; parity percentages are unchanged.
 - **2026-10-24** · Open, Save and the folder dialogs start in the folder of the last file or folder picked in the run (#1290): the Linux portal does not remember it between dialogs as the macOS and Windows panels do. A folder deleted since falls back to the system's choice. No numbers change.
@@ -355,6 +356,7 @@ Ranked; detail and milestones in [`docs/roadmap.md`](docs/roadmap.md).
 | 2026-10-28 | minor | M3, #922: instances scaled with the Scale tool keep their layers' scaled size and points when their main is rebuilt (`size`/`position` overrides recorded on scale). Numbers unchanged. |
 | 2026-10-28 | minor | M6, #1059: `.fig` import copies embedded image blobs once per blob, not once per hash naming them. Numbers unchanged. |
 | 2026-10-28 | minor | M1, #1476: page ruler guides survive save and reopen; files written with a page's `guides` key twice open again with both lists. Numbers unchanged. |
+| 2026-10-27 | minor | M4: zero-length round-capped dashes draw dots; dash expansion uses the existing safety budget; extracted from #1143. Numbers unchanged. |
 | 2026-10-26 | minor | Non-ASCII layer names transliterate in code export (M6, #1235): `class_name` transliterates through the new `deunicode` dependency (pure Rust tables, zero deps, BSD-3-Clause), so Korean, Cyrillic, Latin-diacritic and CJK names become readable ASCII classes (`rogeuin-hwamyeon`, `knopka`, `uber`, `an-niu`) in HTML/CSS/React/Leptos output, component roots and `data-*` variant attributes; symbols-only names take the node's kind (`.text`) instead of `layer-`, and the 40-character cut lands on a word boundary. `html_codegen_tests` updated and extended. Numbers unchanged |
 | 2026-10-25 | minor | egui 0.37 capture lifecycle: screenshots with hidden or unknown visibility queue, request a hidden paint, and expire after 60 seconds if no capture arrives (headless-tested contract). Logic-only edits, saves and inspection continue while hidden. Native visible GUI and forced hidden-window paint, browser and Wayland behavior remain unqualified; parity percentages are unchanged. |
 | 2026-10-24 | minor | Server memory (#1134): when the last person leaves a file nobody edited, figcraft-server keeps the client ids it issued in the log instead of rewriting the snapshot (compaction still follows `compact_after`/`compact_mb` and edits), and a snapshot is encoded straight into its file buffer, without a second copy of the body; the file format is unchanged. Numbers unchanged |

crates/pathops/src/dot_dash_tests.rs

@@ -0,0 +1,40 @@
+use super::*;
+
+#[test]
+fn dense_round_dashes_fall_back_before_expansion() {
+    let mut line = BezPath::new();
+    line.move_to((0.0, 0.0));
+    line.line_to((10_000.0, 0.0));
+    let dangerous = StrokeProps {
+        weight: 2.0,
+        dashes: vec![0.0, 0.02],
+        cap_start: StrokeCap::Round,
+        cap_end: StrokeCap::Round,
+        align: StrokeAlign::Center,
+        ..Default::default()
+    };
+    let outlined = stroke_center(&line, 2.0, &dangerous);
+    let solid = stroke_center(&line, 2.0, &StrokeProps { dashes: vec![], ..dangerous });
+    assert!((outlined.area().abs() - solid.area().abs()).abs() < 0.01);
+    assert!(outlined.elements().len() < 1000, "fallback must not emit hundreds of thousands of dots");
+}
+
+#[test]
+fn zero_length_round_dashes_draw_dots() {
+    let mut line = BezPath::new();
+    line.move_to((0.0, 0.0));
+    line.line_to((100.0, 0.0));
+    let round = StrokeProps {
+        weight: 2.0,
+        dashes: vec![0.0, 9.0],
+        cap_start: StrokeCap::Round,
+        cap_end: StrokeCap::Round,
+        align: StrokeAlign::Center,
+        ..Default::default()
+    };
+    let dots = stroke_center(&line, 2.0, &round);
+    let area = dots.area().abs();
+    assert!((area - 12.0 * std::f64::consts::PI).abs() < 1.5, "{area}");
+    let butt = StrokeProps { cap_start: StrokeCap::None, cap_end: StrokeCap::None, ..round };
+    assert!(stroke_center(&line, 2.0, &butt).area().abs() < 1e-6);
+}

crates/pathops/src/lib.rs

@@ -10,6 +10,8 @@ pub mod brush;
 #[cfg(test)]
 mod brush_tests;
 #[cfg(test)]
+mod dot_dash_tests;
+#[cfg(test)]
 mod ops_tests;
 mod points;
 #[cfg(test)]
@@ -309,7 +311,9 @@ pub fn stroke_center(path: &BezPath, width: f64, props: &StrokeProps) -> BezPath
         .with_end_cap(kcap(props.cap_end));
     // Each subpath restarts the pattern, so it can add up to one more pattern's worth of dashes.
     let subpaths = path.elements().iter().filter(|e| matches!(e, PathEl::MoveTo(_))).count() as f64;
-    if let Some(pat) = width::dash_pattern(props).filter(|p| width::dashes_fit(path.perimeter(1.0) + subpaths * p.iter().sum::<f64>(), p)) {
+    let round = [props.cap_start, props.cap_end].into_iter().any(|c| matches!(kcap(c), Cap::Round));
+    let pattern = width::dash_pattern(props).map(|p| p.into_iter().map(|d| if round && d == 0.0 { 1e-3 } else { d }).collect::<Vec<_>>());
+    if let Some(pat) = pattern.filter(|p| width::dashes_fit(path.perimeter(1.0) + subpaths * p.iter().sum::<f64>(), p)) {
         style = style.with_dashes(0.0, pat);
     }
     kurbo::stroke(path.iter(), &style, &kurbo::StrokeOpts::default(), 0.05)