Part of #394: Preferences that act on selection, the wheel, tool tips and the grid

Fifteen Preferences options were stored but read by nothing. They now act,
through the existing plumbing (ToolContext for the tools, the prefs read by the
canvas for the view), and reach agents through prefs.set:

- General: Show Tool Tips (off: no widget's tool tip comes due), Double Click
  To Isolate, Zoom with Mouse Wheel (the wheel zooms about the pointer,
  Shift-wheel scrolls up and down, Cmd/Ctrl-wheel sideways), Use Precise
  Cursors (Pen, Eyedropper, Slice and Blend pointers become a crosshair).
- Selection & Anchor Display: Tolerance (objects, anchors and handles, in
  place of the fixed 3 and 4 px), Object Selection by Path Only (compound
  paths too), Command Click to Select Objects Behind (cycles down the objects
  under the pointer; not when Cmd only borrows the selection tool), Zoom to
  Selection (Zoom In/Out centre the selection), anchor Size, Highlight anchors
  on mouse over (Direct Selection).
- Type: Number of Recent Fonts (up to 15 Recent Fonts slots).
- Guides & Grid: guide and grid Color and Style (lines or dots), Grids In Back.

The canvas's context menu, panel drops and hover highlight pick objects like
the selection tools. The control channel gets ui.wheel (with modifiers held
like ui.click) so agents can turn the wheel. The rest of #394 stays open.

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

crates/engine/src/tests_prefs.rs

@@ -152,3 +152,78 @@ fn gpu_preference_defaults_to_power_saving_and_validates() {
     s.execute("prefs.reset", &json!({"category": "Performance"})).unwrap();
     assert_eq!(s.prefs.gpu_preference, "powerSaving");
 }
+
+/// Selection & Anchor Display › Tolerance, Object Selection by Path Only and Command Click to
+/// Select Objects Behind, and General › Double Click To Isolate, as the Selection tool sees them
+/// (#394).
+#[test]
+fn selection_preferences_drive_the_selection_tool() {
+    use vectorcraft_tools::{Mods, PointerEvent, PointerKind};
+    let mut s = Session::new();
+    s.execute("file.new", &json!({"width": 400, "height": 400})).unwrap();
+    let rect = |s: &mut Session, x: f64| {
+        NodeId(s.execute("shape.rectangle", &json!({"x": x, "y": 100, "width": 100, "height": 100})).unwrap()["id"].as_u64().unwrap())
+    };
+    // Two filled squares overlapping between x = 150 and 200, `front` on top.
+    let (back, front) = (rect(&mut s, 100.0), rect(&mut s, 150.0));
+    s.select_tool("selection", ViewInfo::default()).unwrap();
+    let set = |s: &mut Session, key: &str, value: Value| s.execute("prefs.set", &json!({"key": key, "value": value})).unwrap();
+    let click = |s: &mut Session, x: f64, mods: Mods| {
+        for k in [PointerKind::Down, PointerKind::Up] {
+            // Halfway between the bounding box's handles.
+            s.pointer(&PointerEvent::new(k, x, 125.0).with_mods(mods), ViewInfo::default()).unwrap();
+        }
+        s.doc().unwrap().selection.objects.clone()
+    };
+    let plain = Mods::default();
+    // Tolerance: the right edge's stroke ends at x = 250.5.
+    assert_eq!(click(&mut s, 252.5, plain), vec![front], "2 px out: within the default 3 px");
+    assert!(click(&mut s, 256.5, plain).is_empty(), "6 px out: beyond 3 px");
+    set(&mut s, "selectionTolerance", json!(8));
+    assert_eq!(click(&mut s, 256.5, plain), vec![front], "6 px out: within 8 px");
+    set(&mut s, "selectionTolerance", json!(1));
+    assert!(click(&mut s, 252.5, plain).is_empty(), "2 px out: beyond 1 px");
+    set(&mut s, "selectionTolerance", json!(3));
+    // Object Selection by Path Only: the fill no longer selects, the path does.
+    assert_eq!(click(&mut s, 225.0, plain), vec![front]);
+    set(&mut s, "objectSelectionByPathOnly", json!(true));
+    assert!(click(&mut s, 225.0, plain).is_empty(), "a click inside the fill selects nothing");
+    assert_eq!(click(&mut s, 250.0, plain), vec![front], "a click on the path selects it");
+    set(&mut s, "objectSelectionByPathOnly", json!(false));
+    // Command Click to Select Objects Behind (on by default): each Cmd/Ctrl-click goes one down,
+    // then back to the top.
+    let cmd = Mods { cmd: true, ..Mods::default() };
+    assert_eq!(click(&mut s, 175.0, plain), vec![front]);
+    assert_eq!(click(&mut s, 175.0, cmd), vec![back], "the object behind");
+    assert_eq!(click(&mut s, 175.0, cmd), vec![front], "back to the topmost");
+    set(&mut s, "ctrlClickSelectsBehind", json!(false));
+    assert_eq!(click(&mut s, 175.0, cmd), vec![front], "off: a plain click");
+    // Double Click To Isolate (on by default) isolates a group; off, it doesn't.
+    s.execute("select.all", &json!({})).unwrap();
+    s.execute("object.group", &json!({})).unwrap();
+    let double = |s: &mut Session| {
+        s.pointer(&PointerEvent::new(PointerKind::DoubleClick, 175.0, 150.0), ViewInfo::default()).unwrap();
+        s.doc().unwrap().isolation
+    };
+    set(&mut s, "doubleClickToIsolate", json!(false));
+    assert_eq!(double(&mut s), None, "off: no isolation");
+    set(&mut s, "doubleClickToIsolate", json!(true));
+    assert!(double(&mut s).is_some(), "on: the group is isolated");
+}
+
+/// General › Use Precise Cursors (#394): the Pen's pointer becomes a crosshair; the Selection
+/// tool's arrow stays.
+#[test]
+fn use_precise_cursors_makes_drawing_cursors_crosshairs() {
+    use vectorcraft_tools::{Cursor, Mods};
+    let mut s = Session::new();
+    s.execute("file.new", &json!({"width": 400, "height": 400})).unwrap();
+    let cursor = |s: &mut Session, tool: &str| {
+        s.select_tool(tool, ViewInfo::default()).unwrap();
+        s.cursor(vectorcraft_geom::Point::new(300.0, 300.0), Mods::default(), ViewInfo::default())
+    };
+    assert_eq!(cursor(&mut s, "pen"), Cursor::Pen);
+    s.execute("prefs.set", &json!({"key": "usePreciseCursors", "value": true})).unwrap();
+    assert_eq!(cursor(&mut s, "pen"), Cursor::Crosshair);
+    assert_eq!(cursor(&mut s, "selection"), Cursor::Arrow);
+}

crates/engine/src/tooling.rs

@@ -152,6 +152,11 @@ impl Session {
             slices_hidden: self.menu.slices_hidden,
             slices_locked: self.menu.slices_locked,
             auto_add_delete: !self.prefs.disable_auto_add_delete,
+            selection_tolerance: self.prefs.selection_tolerance,
+            path_only: self.prefs.object_selection_by_path_only,
+            double_click_isolate: self.prefs.double_click_to_isolate,
+            select_behind: self.prefs.ctrl_click_selects_behind,
+            highlight_anchors: self.prefs.highlight_anchors_on_hover,
             screen: view.screen,
             plane_widget: self.prefs.perspective_widget.show.then_some(self.prefs.perspective_widget.position),
         };
@@ -265,8 +270,11 @@ impl Session {
         v
     }
 
+    /// The pointer the active tool shows at `p` (General › Use Precise Cursors makes the drawing
+    /// tools' a crosshair, [`Cursor::precise`]).
     pub fn cursor(&mut self, p: Point, mods: Mods, view: ViewInfo) -> Cursor {
-        self.with_tool_cx(view, |t, cx| t.cursor(cx, p, mods))
+        let c = self.with_tool_cx(view, |t, cx| t.cursor(cx, p, mods));
+        if self.prefs.use_precise_cursors { c.precise() } else { c }
     }
 
     pub fn tool_options(&self) -> Value {