Blob Brush: a round tip's preview is the outline of the area, round at both ends (#4343)

While painting, a round Blob Brush showed a line as wide as the brush, which ends
square, though the stroke it adds is round at both ends. Only an angled or flattened
tip showed the outline of the area. The Blob Brush now shows that outline whatever
its roundness (blob_area, which path.blob's stroke matches).

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

crates/tools/src/draw2/gesture.rs

@@ -782,8 +782,10 @@ impl Tool for GestureTool {
         };
         let color = if self.id == "eraser" { [0x80, 0x80, 0x80] } else { FEEDBACK };
         // A tip that is not round shows the outline of the area it covers, each step of the drag
-        // as wide as the pen pressed there with Size set to Pressure.
-        if matches!(self.id, "eraser" | "blobBrush") && self.roundness < 100.0 && !self.smoothing {
+        // as wide as the pen pressed there with Size set to Pressure. So does a round Blob Brush
+        // tip: a line as wide as the brush would end square, where the stroke it adds is round at
+        // both ends (#4343).
+        if matches!(self.id, "eraser" | "blobBrush") && (self.roundness < 100.0 || self.id == "blobBrush") && !self.smoothing {
             let area = |pts: &[Point], size| {
                 if self.id == "blobBrush" {
                     blob_area(pts, size, self.angle, self.roundness)

crates/tools/src/draw2/gesture/tests.rs

@@ -382,6 +382,36 @@ fn blob_brush_drag_shows_scrub_length_measurement_labels() {
     assert!(!quiet.overlays(&off).iter().any(|o| matches!(o, Overlay::Measure { .. })));
 }
 
+/// #4343: while it is dragged, a round Blob Brush shows the outline of the area `path.blob` adds,
+/// which reaches half the brush beyond the ends of the stroke (round tips), not a line as wide as
+/// the brush that ends square at them.
+#[test]
+fn blob_brush_preview_is_the_outline_of_the_area_with_round_tips() {
+    use vectorcraft_geom::kurbo::Shape;
+    let (d, _) = doc_with_rect();
+    let s = Selection::default();
+    let p = paint();
+    let cx = cx(&d, &s, &p);
+    let mut t = GestureTool::new("blobBrush");
+    t.size = 20.0;
+    assert_eq!(t.roundness, 100.0, "a round tip by default");
+    t.pointer(&cx, &PointerEvent::new(PointerKind::Down, 50.0, 300.0));
+    t.pointer(&cx, &PointerEvent::new(PointerKind::Drag, 150.0, 300.0));
+    let outlines: Vec<_> =
+        t.overlays(&cx).into_iter().filter_map(|o| if let Overlay::Path { path, width, .. } = o { Some((path, width)) } else { None }).collect();
+    assert!(outlines.iter().all(|(_, width)| f64::from(*width) < t.size / 2.0), "no line as wide as the brush: {outlines:?}");
+    // The stroke's outline is the widest one (the tip at the pointer is another).
+    let Some((path, _)) = outlines.iter().max_by(|a, b| a.0.bounding_box().width().total_cmp(&b.0.bounding_box().width())) else {
+        panic!("no outline")
+    };
+    let b = path.bounding_box();
+    assert!((b.x0 - 40.0).abs() < 0.5 && (b.x1 - 160.0).abs() < 0.5, "round tips reach half the size past the ends: {b:?}");
+    assert!((b.y0 - 290.0).abs() < 0.5 && (b.y1 - 310.0).abs() < 0.5, "{b:?}");
+    // Round, not square: the corner of the box a square-ended line would fill is outside the area.
+    assert!(!path.contains(vectorcraft_geom::Point::new(41.0, 291.0)));
+    assert!(path.contains(vectorcraft_geom::Point::new(45.0, 300.0)));
+}
+
 /// The Blob Brush has Keep selected and Merge only with selection, both off by default, and its
 /// stroke sends both.
 #[test]

docs/ui-parity.md

@@ -1,6 +1,6 @@
 # UI and interaction parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-11-11 · **Change:** minor (G5: Inventory Icons built-in symbol library (four built-ins); previously minor: files that record no units open in Preferences › Units › General, #5820; previously minor: interim macOS cursor delivery, #2292; native validation pending; scores and estimates unchanged; Control bar › Snapping includes the existing Snap to Glyph and Alignment Guides toggles (#6164); scores and estimates unchanged; floating tab groups collapse into the side icon rail and opened rail panels fold back into it, #5925 in part; numeric fields step on wheel hover without taking keyboard focus, #5949; Character Styles panel: a double-click on a style's row opens its Character Style Options; the dialog keeps a fixed width and scrolls its sections, so its buttons stay on screen; Selection QoL: marquee modes and visible feedback, #5313; #3380 deletion-only review follow-up: independent survivors keep gradient placement, owned subpaths avoid discarded copies, and contracts/status/evidence are clarified; endpoint highlighting remains open; scores and estimates unchanged; Drop Shadow and glow dialogs: spinner arrows, #5367, #5368; Stroke Weight Up and Down shortcuts, #5797; Layers: Rename (`ui.rename`) opens the name field of the selected layer, group or object, #5324; Properties in Edit Artboards: Transform section above the Artboards section, #5219; scrubby labels: the Control bar's Stroke: and Opacity: links and the Properties panel's Stroke link scrub their fields, #4088; Properties: Quick Actions has Repeat Options for one selected repeat, #5181; Direct Selection: Shift-click picks several blend spine points, which drag together, #5285; Direct Selection: Cmd/Ctrl held lends the Selection tool and shows its bounding box, #3901; Join tool trims two crossing open paths and joins them at the crossing, #5844; Control bar: Paragraph: link and Align left/center/right while type is selected, #5372; shape tools: a press on the selection's centre point moves it and one in the rotate zone outside a box corner turns it, #5477; scores and estimates unchanged) · **Target:** Adobe Illustrator 2026 (30.x; Units › East Asian Type acts, with Q and Ha units; scores unchanged)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-11-11 · **Change:** minor (Blob Brush: a round tip's preview is the outline of the area it adds, round at both ends, as the stroke it commits (#4343); scores and estimates unchanged; previously:; G5: Inventory Icons built-in symbol library (four built-ins); previously minor: files that record no units open in Preferences › Units › General, #5820; previously minor: interim macOS cursor delivery, #2292; native validation pending; scores and estimates unchanged; Control bar › Snapping includes the existing Snap to Glyph and Alignment Guides toggles (#6164); scores and estimates unchanged; floating tab groups collapse into the side icon rail and opened rail panels fold back into it, #5925 in part; numeric fields step on wheel hover without taking keyboard focus, #5949; Character Styles panel: a double-click on a style's row opens its Character Style Options; the dialog keeps a fixed width and scrolls its sections, so its buttons stay on screen; Selection QoL: marquee modes and visible feedback, #5313; #3380 deletion-only review follow-up: independent survivors keep gradient placement, owned subpaths avoid discarded copies, and contracts/status/evidence are clarified; endpoint highlighting remains open; scores and estimates unchanged; Drop Shadow and glow dialogs: spinner arrows, #5367, #5368; Stroke Weight Up and Down shortcuts, #5797; Layers: Rename (`ui.rename`) opens the name field of the selected layer, group or object, #5324; Properties in Edit Artboards: Transform section above the Artboards section, #5219; scrubby labels: the Control bar's Stroke: and Opacity: links and the Properties panel's Stroke link scrub their fields, #4088; Properties: Quick Actions has Repeat Options for one selected repeat, #5181; Direct Selection: Shift-click picks several blend spine points, which drag together, #5285; Direct Selection: Cmd/Ctrl held lends the Selection tool and shows its bounding box, #3901; Join tool trims two crossing open paths and joins them at the crossing, #5844; Control bar: Paragraph: link and Align left/center/right while type is selected, #5372; shape tools: a press on the selection's centre point moves it and one in the rotate zone outside a box corner turns it, #5477; scores and estimates unchanged) · **Target:** Adobe Illustrator 2026 (30.x; Units › East Asian Type acts, with Q and Ha units; scores unchanged)
 >
 > Vector Halftone preview update (2026-11-10): temporary dot selection marks are hidden, and the bounding box stays available (#6369).
 >
@@ -157,7 +157,7 @@ tools, never checked side by side) isn't captured row by row.
 | Anchor Point and Curvature tools' own cursors | done | the caret on the anchor it converts; the pen nib with a curve badge |
 | Free Transform's Cmd/Ctrl side-shear cursor | done | two arrows passing along the side (ShearH, ShearV), instead of the resize arrow across it |
 | Cursors of their own for Lasso, Magic Wand, the freehand tools, Shaper, Live Paint Bucket, Measure, Print Tiling, the symbolism tools, vertical type, Scissors (over a segment and away), Mesh and Puppet Warp | partial | each tool returns its own cursor and Use Precise Cursors turns them into the crosshair; until they're drawn they borrow the crosshair, the I-beam, the Pen's add cursor or not-allowed |
-| Blob Brush and Eraser: the tip's outline at the pointer | done | before a press and while painting, the outline of the tip (its size, angle and roundness, at the zoom) follows the pointer, black on a white halo, round a small centre dot; `[` / `]` and Tool Options change it at once; precise cursors (Caps Lock) show only the crosshair; it goes when the pointer leaves the canvas, while Cmd/Ctrl lends a selection tool and while Alt lends the Blob Brush the Smooth tool (#4977); `crates/tools/src/draw2/gesture.rs` and its tests |
+| Blob Brush and Eraser: the tip's outline at the pointer | done | before a press and while painting, the outline of the tip (its size, angle and roundness, at the zoom) follows the pointer, black on a white halo, round a small centre dot; `[` / `]` and Tool Options change it at once; precise cursors (Caps Lock) show only the crosshair; it goes when the pointer leaves the canvas, while Cmd/Ctrl lends a selection tool and while Alt lends the Blob Brush the Smooth tool (#4977); `crates/tools/src/draw2/gesture.rs` and its tests While the button is down a round Blob Brush shows the outline of the area it will add, rounded at both ends, not a line as wide as the brush that ends square (#4343). |
 | Busy cursor during long operations | done | Background open, save and export show the system progress cursor (gap G1) |
 | Each anchor snaps to Smart Guides and construction angles | done | `DrawSnap` |
 | Curvature tool: click/drag points, double-click or Alt-click for a corner, temporary Direct Selection, point conversion | partial | circular point markers without direction handles or duplicate markers, Anchor Size and Hide Edges regression-tested (#1236, in part); curve geometry: each stretch of three points follows the circle through them (handles along its tangent, chord/(3·cos²(α/2)) long, shorter in a turn tighter than 30°), open ends curving in, the same rule for the rubber band, dragged, inserted and converted points (#1236, in part); neighbours of a point dragged on an existing path keep their tangents, and modifiers requested in #975 remain |
@@ -546,6 +546,7 @@ separate. Scores and hours unchanged. [Behavior and command details](development
 | 2026-11-01 | minor | Arrange Tools add-on (a VectorCraft addition): Randomize Opacity (#4925); scores and estimates unchanged |
 | 2026-11-01 | minor | Arrange Tools add-on (a VectorCraft addition): Sort Objects (#4917); scores and estimates unchanged |
 | 2026-11-01 | minor | Blob Brush and Eraser: the tip's outline (size, angle, roundness, at the zoom) follows the pointer before and while painting, around a small centre dot, updating at once with `[` / `]` and Tool Options; precise cursors (Caps Lock) show only the crosshair (#4977); scores and estimates unchanged (estimated) |
+| 2026-11-11 | minor | Blob Brush: while painting, the preview of a round tip is the outline of the area the stroke adds, round at both ends, as the stroke it commits (#4343). Scores unchanged (estimated). |
 | 2026-11-01 | minor | Layers panel: an open blend lists its spine as a `<Path>` row below its key objects, and a click selects the blend so Direct Selection edits the spine (#4820); scores and estimates unchanged |
 | 2026-11-01 | minor | Pen with Cmd/Ctrl held: the lent Selection tool no longer scales the path being drawn by bounding-box handles the canvas hides while its end anchor is selected (a flat path did nothing under a resize pointer); a Cmd drag moves the path instead, and with Direct Selection moves anchors and segments, one undo step each (#4980); scores and estimates unchanged |
 | 2026-11-01 | minor | Dynamic symbols (#4938): Symbol Options › Symbol Type; per-instance appearance for objects of a dynamic symbol's art; Reset in the Properties panel and the Symbols panel menu; on-canvas Direct Selection of the parts remains |