fix(ui): Sketch Palette line type buttons follow the selected curves (#422)

With sketch curves selected, the palette's Normal / Construction / Centerline
buttons now show the line type of the selection (each type of a mixed
selection); with nothing selected they show the drawing mode, as before.
Previously no button was highlighted while curves were selected.

Co-authored-by: Claude Opus 5.5 <[email protected]>

crates/ui-egui/src/sketch_palette.rs

@@ -128,6 +128,31 @@ fn selected_curves(app: &SolveApp) -> Vec<String> {
     app.session.selection.iter().filter_map(|s| if let Sel::SketchCurve { id } = s { Some(id.clone()) } else { None }).collect()
 }
 
+/// The line types among the selected curves of the active sketch, indexed like the palette's
+/// buttons (0 normal, 1 construction, 2 centerline); a mixed selection marks each of its types.
+fn selected_linetypes(app: &SolveApp) -> [bool; 3] {
+    let mut types = [false; 3];
+    let curves = selected_curves(app);
+    if curves.is_empty() {
+        return types;
+    }
+    let st = app.session.world_state();
+    let Some(ss) = app.session.active_sketch.and_then(|s| st.sketch(s)) else { return types };
+    for c in curves.iter().filter_map(|id| ss.sketch.curve_index(id).and_then(|i| ss.sketch.curves.get(i))) {
+        let k = if c.centerline {
+            2
+        } else if c.construction {
+            1
+        } else {
+            0
+        };
+        if let Some(t) = types.get_mut(k) {
+            *t = true;
+        }
+    }
+    types
+}
+
 /// Set the line type of the selected curves: 0 normal, 1 construction, 2 centerline (lines).
 pub fn set_linetype(app: &mut SolveApp, kind: u8) {
     let curves = selected_curves(app);
@@ -205,6 +230,7 @@ pub fn show(app: &mut SolveApp, ctx: &egui::Context) {
     let mut look = false;
     let mut finish = false;
     let has_curves = !selected_curves(app).is_empty();
+    let selected_types = selected_linetypes(app);
     let response = crate::frame::docked(
         app.tr("ui.heading_sketch_palette"),
         egui::Id::new("sc_sketch_palette"),
@@ -241,10 +267,11 @@ pub fn show(app: &mut SolveApp, ctx: &egui::Context) {
                     ui.vertical(|ui| {
                         ui.label(app.tr("ui.linetype"));
                         ui.horizontal(|ui| {
-                            // With a selection: convert it; without: the mode new curves are drawn in.
+                            // With a selection: its line type, and a click converts it; without:
+                            // the mode new curves are drawn in.
                             let current = mode(app);
                             for (i, (label, tip)) in [("—", "Normal"), ("- -", "Construction"), ("-·-", "Centerline")].iter().enumerate() {
-                                let on = !has_curves && current == i as u8;
+                                let on = if has_curves { selected_types.get(i).copied().unwrap_or(false) } else { current == i as u8 };
                                 let tr_tip = app.tr_label(tip);
                                 let tip = if has_curves {
                                     crate::i18n::format("sketch.make_selection", &[("linetype", tr_tip)])
@@ -352,6 +379,38 @@ mod tests {
         }
     }
 
+    #[test]
+    fn linetype_buttons_follow_the_selection_and_fall_back_to_the_mode() {
+        let mut h = crate::scenario::Harness::new();
+        h.app.run("sketch.create", json!({"plane":"XY"})).unwrap();
+        let curve = |r: Value| r["curves"][0].as_str().unwrap().to_string();
+        let normal = curve(h.app.run("sketch.line", json!({"points":[[0,0],[20,0]],"infer":false,"connect":false})).unwrap());
+        let cons = curve(h.app.run("sketch.line", json!({"points":[[0,10],[20,10]],"infer":false,"connect":false})).unwrap());
+        let center = curve(h.app.run("sketch.line", json!({"points":[[0,20],[20,20]],"infer":false,"connect":false})).unwrap());
+        h.app.run("sketch.construction", json!({"curves":[cons],"value":true})).unwrap();
+        h.app.run("sketch.centerline", json!({"curves":[center],"value":true})).unwrap();
+        // Which of Normal, Construction and Centerline the palette shows pressed.
+        let pressed = |h: &mut crate::scenario::Harness, ids: &[&String]| {
+            h.app.session.selection = ids.iter().map(|id| Sel::SketchCurve { id: (*id).clone() }).collect();
+            h.settle();
+            let tree = h.output.accesskit_update.as_ref().unwrap();
+            ["—", "- -", "-·-"]
+                .map(|label| tree.nodes.iter().any(|(_, n)| n.label() == Some(label) && n.toggled() == Some(egui::accesskit::Toggled::True)))
+        };
+        assert_eq!(pressed(&mut h, &[&normal]), [true, false, false]);
+        assert_eq!(pressed(&mut h, &[&cons]), [false, true, false]);
+        assert_eq!(pressed(&mut h, &[&center]), [false, false, true]);
+        // A mixed selection shows each of its line types.
+        assert_eq!(pressed(&mut h, &[&normal, &center]), [true, false, true]);
+        // Nothing selected: the drawing mode.
+        assert_eq!(pressed(&mut h, &[]), [true, false, false]);
+        set_mode(&mut h.app, 1);
+        assert_eq!(pressed(&mut h, &[]), [false, true, false]);
+        // A selection overrides the mode until it is cleared.
+        assert_eq!(pressed(&mut h, &[&normal]), [true, false, false]);
+        assert_eq!(pressed(&mut h, &[]), [false, true, false]);
+    }
+
     #[test]
     fn dof_readout() {
         assert_eq!(dof_text(0, true), "Fully constrained");