Restore a view's visual style; no background in 2D wireframe

Restoring a named view gives the model viewport the view's visual style
(the closest render mode), and a 2D wireframe viewport shows no
background, as in the reference.

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

src/app/commands/layerprops.rs

@@ -909,6 +909,7 @@ impl OpenCADStudio {
                             let found = self.tabs[i].scene.document.views.get(&name).cloned();
                             if let Some(v) = found {
                                 self.tabs[i].scene.restore_named_view(&v);
+                            self.apply_view_render_mode(i, &v);
                                 self.command_line.push_output(
                                     crate::tf!("View '{}' restored.", v.name).as_ref(),
                                 );
@@ -932,6 +933,7 @@ impl OpenCADStudio {
                         let found = self.tabs[i].scene.document.views.get(&name).cloned();
                         if let Some(v) = found {
                             self.tabs[i].scene.restore_named_view(&v);
+                            self.apply_view_render_mode(i, &v);
                             self.command_line
                                 .push_output(crate::tf!("View '{}' restored.", v.name).as_ref());
                         } else {

src/app/commands/view_presets.rs

@@ -144,6 +144,7 @@ impl OpenCADStudio {
                 };
                 let before = self.tabs[i].scene.active_gaze_dir();
                 self.tabs[i].scene.restore_named_view(&view);
+                self.apply_view_render_mode(i, &view);
                 if view.ucs_associated && self.tabs[i].active_block_edit.is_none() {
                     let world = view.ucs_x_axis == Vector3::new(1.0, 0.0, 0.0)
                         && view.ucs_y_axis == Vector3::new(0.0, 1.0, 0.0)
@@ -543,3 +544,33 @@ impl OpenCADStudio {
         Task::none()
     }
 }
+
+impl OpenCADStudio {
+    /// A restored view's visual style becomes the model tab's render mode
+    /// (the closest of OCS's modes); a view without one leaves it.
+    pub(crate) fn apply_view_render_mode(&mut self, i: usize, view: &codec::tables::View) {
+        use codec::entities::ViewportRenderMode as M;
+        if self.tabs[i].scene.current_layout != "Model" {
+            return;
+        }
+        let Some(ObjectType::VisualStyle(style)) =
+            self.tabs[i].scene.document.objects.get(&view.visual_style_handle)
+        else {
+            return;
+        };
+        let (mode, label) = match style.description.as_str() {
+            "2dWireframe" => (M::Wireframe2D, "Wireframe 2D"),
+            "Wireframe" => (M::Wireframe3D, "Wireframe 3D"),
+            "Hidden" => (M::HiddenLine, "Hidden Line"),
+            "Flat" => (M::FlatShaded, "Flat Shaded"),
+            "FlatWithEdges" => (M::FlatShadedWithEdges, "Flat Shaded + Edges"),
+            "GouraudWithEdges" | "Shaded with edges" => {
+                (M::GouraudShadedWithEdges, "Gouraud Shaded + Edges")
+            }
+            "Gouraud" | "Realistic" | "Shaded" | "Conceptual" | "Shades of Gray" | "Sketchy"
+            | "X-Ray" => (M::GouraudShaded, "Gouraud Shaded"),
+            _ => return,
+        };
+        self.apply_render_mode(i, mode, label);
+    }
+}

src/app/update/viewport.rs

@@ -1090,6 +1090,24 @@ impl OpenCADStudio {
                 .push_output(crate::tf!("Viewport visual style: {label}").as_ref());
             return Task::none();
         }
+        self.apply_render_mode(i, mode, label);
+        self.command_line
+            .push_output(crate::tf!("Visual style: {label}").as_ref());
+        // The point cloud move gizmo follows the visual style.
+        if i == self.active_tab {
+            self.refresh_selected_grips();
+        }
+        Task::none()
+    }
+
+    /// The model tab's visual style, without a message.
+    pub(crate) fn apply_render_mode(
+        &mut self,
+        i: usize,
+        mode: codec::entities::ViewportRenderMode,
+        label: &str,
+    ) {
+        use codec::entities::ViewportRenderMode as M;
         self.tabs[i].render_mode = mode;
         // Write the style onto the active Model tile alone so it
         // sticks when that tile loses focus and the other tiles keep
@@ -1105,13 +1123,6 @@ impl OpenCADStudio {
         // pipeline keys its upload cache off `geometry_epoch`.
         self.tabs[i].scene.bump_geometry_no_blocks();
         self.tabs[i].dirty = true;
-        self.command_line
-            .push_output(crate::tf!("Visual style: {label}").as_ref());
-        // The point cloud move gizmo follows the visual style.
-        if i == self.active_tab {
-            self.refresh_selected_grips();
-        }
-        Task::none()
     }
 
     pub(super) fn on_cursor_moved(

src/scene/camera_ops.rs

@@ -219,6 +219,13 @@ impl Scene {
         if self.current_layout == "Model" {
             let background = copy_background(&mut self.document, view.background_handle);
             self.set_active_background(background);
+            if view.visual_style_handle.is_valid() {
+                if let Some(handle) = self.active_tile_vport_handle() {
+                    if let Some(value) = self.document.vports.iter_mut().find(|v| v.handle == handle) {
+                        value.visual_style_handle = view.visual_style_handle;
+                    }
+                }
+            }
         }
         let cam = &mut *self.camera.borrow_mut();
         // The stored direction points from the target toward the eye.

src/scene/view/render.rs

@@ -2571,11 +2571,15 @@ impl Scene {
         } else if self.current_layout == "Model" {
             let index = viewport.tile_idx.unwrap_or(0);
             if let Some(value) = self.model_tile_vport(index) {
+                // A 2D wireframe view shows no background, as in the reference.
+                let flat = self.model_tiles.borrow().get(index).is_some_and(|tile| {
+                    tile.render_mode == codec::entities::ViewportRenderMode::Wireframe2D
+                });
                 return build(
                     value.visual_style_handle,
                     value.brightness,
                     value.contrast,
-                    value.background_handle,
+                    if flat { Handle::NULL } else { value.background_handle },
                 );
             }
         }