Merge PR #353: fix View Cube toggle (highlight follows state, cube clears on hide)

External PR by Karim Jerbi (@KarimJerbi).
- NAVVCUBE is a command toggle so it never set active_tool; add a
  show_viewcube flag to the ribbon and special-case is_active_tool so the
  button highlights only while the cube is on.
- show_viewcube was absent from render_signature, so toggling a cached
  view produced an identical signature and left stale cube pixels; hash
  it into the signature so the toggle invalidates the cache and clears.

src/app/update/mod.rs

@@ -1562,6 +1562,7 @@ impl OpenCADStudio {
             }
             Message::ToggleViewCube => {
                 self.show_viewcube ^= true;
+                self.ribbon.set_viewcube(self.show_viewcube);
                 Task::none()
             }
             Message::ToggleProperties => {

src/scene/view/render.rs

@@ -514,6 +514,11 @@ fn render_signature(vp: &ViewportData, clip_w: u32, clip_h: u32) -> u64 {
     vp.mesh_fill.hash(&mut h);
     vp.show_3d_edges.hash(&mut h);
     vp.hidden_line.hash(&mut h);
+    // ViewCube visibility is excluded from the *scene* signature elsewhere only
+    // for the live-hover pass; here it MUST invalidate the cache so toggling the
+    // cube (NAVVCUBE) re-renders and actually clears the last cube frame
+    // instead of leaving its stale pixels on the cached surface.
+    vp.show_viewcube.hash(&mut h);
     // Interaction-LOD hatch suppression: differs the signature so the settle
     // frame (skip_hatch flips false) re-renders with hatches and re-caches.
     vp.skip_hatch.hash(&mut h);

src/ui/ribbon/mod.rs

@@ -35,6 +35,8 @@ pub struct Ribbon {
     active_tool: Option<String>,
     pub wireframe: bool,
     pub ortho_mode: bool,
+    /// ViewCube (NAVVCUBE) visibility — drives the View Cube button highlight.
+    pub show_viewcube: bool,
     pub open_dropdown: Option<String>,
     /// Title of the collapsed panel whose flyout is currently open, if any.
     pub collapsed_open: Option<String>,
@@ -133,6 +135,7 @@ impl Ribbon {
             active_tool: None,
             wireframe: false,
             ortho_mode: true,
+            show_viewcube: true,
             open_dropdown: None,
             collapsed_open: None,
             last_panel_tool: HashMap::default(),
@@ -274,6 +277,9 @@ impl Ribbon {
     pub fn set_ortho(&mut self, ortho: bool) {
         self.ortho_mode = ortho;
     }
+    pub fn set_viewcube(&mut self, on: bool) {
+        self.show_viewcube = on;
+    }
 
     pub fn toggle_dropdown(&mut self, id: &str) {
         if self.open_dropdown.as_deref() == Some(id) {
@@ -536,6 +542,7 @@ impl Ribbon {
                             &self.last_cmd,
                             self.wireframe,
                             self.ortho_mode,
+                            self.show_viewcube,
                             &self.layer_infos,
                             &self.active_layer,
                             self.active_color,
@@ -551,6 +558,7 @@ impl Ribbon {
                             &self.last_cmd,
                             self.wireframe,
                             self.ortho_mode,
+                            self.show_viewcube,
                             &self.layer_infos,
                             &self.active_layer,
                             self.active_color,
@@ -566,6 +574,7 @@ impl Ribbon {
                             &self.last_cmd,
                             self.wireframe,
                             self.ortho_mode,
+                            self.show_viewcube,
                             &self.layer_infos,
                             &self.active_layer,
                             self.active_color,
@@ -582,6 +591,7 @@ impl Ribbon {
                             &self.last_cmd,
                             self.wireframe,
                             self.ortho_mode,
+                            self.show_viewcube,
                             &self.layer_infos,
                             &self.active_layer,
                             self.active_color,
@@ -598,6 +608,7 @@ impl Ribbon {
                             &self.last_cmd,
                             self.wireframe,
                             self.ortho_mode,
+                            self.show_viewcube,
                             &self.layer_infos,
                             &self.active_layer,
                             self.active_color,
@@ -1291,6 +1302,7 @@ fn render_group<'a>(
     last_cmd: &HashMap<&'static str, &'static str>,
     wireframe: bool,
     ortho_mode: bool,
+    show_viewcube: bool,
     layer_infos: &'a [LayerInfo],
     active_layer: &'a str,
     active_color: AcadColor,
@@ -1319,6 +1331,7 @@ fn render_group<'a>(
                 last_cmd,
                 wireframe,
                 ortho_mode,
+                show_viewcube,
                 layer_infos,
                 active_layer,
                 active_color,
@@ -1335,6 +1348,7 @@ fn render_group<'a>(
                 last_cmd,
                 wireframe,
                 ortho_mode,
+                show_viewcube,
             ));
             if small_buf.len() == 3 {
                 flush_small_col(&mut small_buf, &mut items_row);
@@ -1414,6 +1428,7 @@ fn collapse_button<'a>(
     last_cmd: &HashMap<&'static str, &'static str>,
     wireframe: bool,
     ortho_mode: bool,
+    show_viewcube: bool,
     layer_infos: &'a [LayerInfo],
     active_layer: &'a str,
     active_color: AcadColor,
@@ -1481,6 +1496,7 @@ fn collapse_button<'a>(
             last_cmd,
             wireframe,
             ortho_mode,
+            show_viewcube,
             layer_infos,
             active_layer,
             active_color,
@@ -1496,6 +1512,7 @@ fn collapse_button<'a>(
             last_cmd,
             wireframe,
             ortho_mode,
+            show_viewcube,
             layer_infos,
             active_layer,
             active_color,

src/ui/ribbon/widgets.rs

@@ -289,12 +289,14 @@ pub(super) fn is_active_tool(
     active_tool: &Option<String>,
     wireframe: bool,
     ortho_mode: bool,
+    show_viewcube: bool,
 ) -> bool {
     match id {
         "WIREFRAME" => wireframe,
         "SOLID" => !wireframe,
         "ORTHO" => ortho_mode,
         "PERSP" => !ortho_mode,
+        "NAVVCUBE" => show_viewcube,
         id => active_tool.as_deref() == Some(id),
     }
 }
@@ -349,12 +351,13 @@ pub(super) fn render_small<'a>(
     last_cmd: &HashMap<&'static str, &'static str>,
     wireframe: bool,
     ortho_mode: bool,
+    show_viewcube: bool,
 ) -> Element<'a, Message> {
     match item {
         // Large variants render small too, so the ribbon can shrink a panel of
         // large buttons to icon-only columns when the width is tight.
         RibbonItem::Tool(t) | RibbonItem::LargeTool(t) => {
-            let active = is_active_tool(t.id, active_tool, wireframe, ortho_mode);
+            let active = is_active_tool(t.id, active_tool, wireframe, ortho_mode, show_viewcube);
             let event = t.event.clone();
             let tool_id = t.id.to_string();
             let tip_text = format!("{}\nCommand: {}", t.label, t.id);
@@ -584,6 +587,7 @@ pub(super) fn render_large<'a>(
     last_cmd: &HashMap<&'static str, &'static str>,
     wireframe: bool,
     ortho_mode: bool,
+    show_viewcube: bool,
     layer_infos: &'a [LayerInfo],
     active_layer: &'a str,
     active_color: AcadColor,
@@ -597,7 +601,7 @@ pub(super) fn render_large<'a>(
         // A plain Tool renders large too, so a collapsed panel can show its
         // representative tool as a big icon.
         RibbonItem::LargeTool(t) | RibbonItem::Tool(t) => {
-            let active = is_active_tool(t.id, active_tool, wireframe, ortho_mode);
+            let active = is_active_tool(t.id, active_tool, wireframe, ortho_mode, show_viewcube);
             let event = t.event.clone();
             let tool_id = t.id.to_string();
             let tip_text = format!("{}\nCommand: {}", t.label, t.id);
@@ -783,9 +787,10 @@ pub(super) fn render_large<'a>(
                     last_cmd,
                     wireframe,
                     ortho_mode,
+                    show_viewcube,
                 )
             } else {
-                let mp_active = is_active_tool(match_prop.id, active_tool, wireframe, ortho_mode);
+                let mp_active = is_active_tool(match_prop.id, active_tool, wireframe, ortho_mode, show_viewcube);
                 let mp_event = match_prop.event.clone();
                 let mp_id = match_prop.id.to_string();
                 let mp_tip = format!("{}\nCommand: {}", match_prop.label, match_prop.id);