address review: close scribbles at the release point; keep vertices when a capped press adds none

crates/engine/src/tests.rs

@@ -5039,6 +5039,22 @@ fn a_long_ink_stroke_is_extended_in_place_and_capped() {
     assert!((2..=tools::MAX_GESTURE_POINTS).contains(&kept), "{kept}");
 }
 
+#[test]
+fn double_clicking_a_capped_freeform_keeps_its_vertices() {
+    let mut s = session();
+    let ev = |kind, x: f64, y: f64| tools::PointerEvent { kind, x, y, mods: Default::default(), tol: 3.0, pressure: None };
+    s.set_tool(tools::ToolKind::Shape { preset: "freeform".into() });
+    s.pointer(ev(tools::PointerKind::Down, 100.0, 100.0)).unwrap();
+    // Densely clicked vertices, each within the double-click tolerance of the last.
+    for i in 0..tools::MAX_GESTURE_POINTS + 10 {
+        s.pointer(ev(tools::PointerKind::Down, 300.0 + i as f64 * 0.001, 100.0)).unwrap();
+    }
+    s.pointer(ev(tools::PointerKind::DoubleClick, 300.0, 100.0)).unwrap();
+    let st = s.doc().unwrap();
+    let deckcraft_model::Geom::Custom { paths } = &st.shapes().last().unwrap().geom else { panic!("no freeform") };
+    assert_eq!(paths[0].d.matches(" L ").count(), tools::MAX_GESTURE_POINTS - 1);
+}
+
 fn ink_pressures(s: &Session) -> Vec<Vec<f32>> {
     let st = s.doc().unwrap();
     let Some(sh) = st.shapes().iter().rev().find(|sh| matches!(sh.kind, deckcraft_model::ShapeKind::Ink { .. })) else {

crates/engine/src/tools.rs

@@ -276,6 +276,8 @@ pub struct ToolState {
     pub path_preview: Vec<Point>,
     pub path_smooth: bool,
     pub path_closing: bool,
+    /// Whether the last freeform press added a vertex (it adds none at the point cap).
+    pub press_added_vertex: bool,
     /// The shape in Edit Points: its vertices are handles instead of the box's.
     pub edit_points: Option<ShapeId>,
     /// The vertex (path, index) whose control handles show in Edit Points.

crates/engine/src/tools/click.rs

@@ -4,8 +4,12 @@ use super::{Drag, Hit, Point, Result, Session, ShapeId, ShapeKind, TextSel, Tool
 impl Session {
     pub(super) fn double_click(&mut self, p: Point, tol: f64) -> Result<Value> {
         if let Some(Drag::Freeform { mode, mut points, .. }) = self.tool.drag.clone() {
-            // The double-click's own click added a duplicate vertex.
-            while points.len() > 2 && points.last().zip(points.get(points.len() - 2)).is_some_and(|(a, b)| (*a - *b).hypot() <= tol) {
+            // The double-click's own click added a duplicate vertex (none at the point cap, where
+            // the existing vertices are all kept).
+            while self.tool.press_added_vertex
+                && points.len() > 2
+                && points.last().zip(points.get(points.len() - 2)).is_some_and(|(a, b)| (*a - *b).hypot() <= tol)
+            {
                 points.pop();
             }
             self.tool.drag = Some(Drag::Freeform { mode, points, pressed: false });

crates/engine/src/tools/pointer.rs

@@ -228,7 +228,8 @@ impl Session {
                 self.tool.drag = Some(Drag::Freeform { mode, points, pressed: false });
                 return self.finish_freeform(true);
             }
-            if points.len() < super::MAX_GESTURE_POINTS {
+            self.tool.press_added_vertex = points.len() < super::MAX_GESTURE_POINTS;
+            if self.tool.press_added_vertex {
                 points.push(p);
             }
             self.tool.path_preview = points.clone();
@@ -551,7 +552,7 @@ impl Session {
             Some(Drag::Freeform { mode, points, .. }) => {
                 if mode == "scribble" {
                     // A scribble ending back at its start closes into a filled shape.
-                    let closed = points.len() > 3 && points.first().zip(points.last()).is_some_and(|(a, b)| (*a - *b).hypot() <= 6.0);
+                    let closed = points.len() > 3 && points.first().is_some_and(|a| (*a - p).hypot() <= 6.0);
                     self.tool.drag = Some(Drag::Freeform { mode, points, pressed: false });
                     return self.finish_freeform(closed);
                 }