Set a transform on the root AccessKit node (#764)

This is better than having to apply the scale factor to the bounding
rectangles of all nodes, especially when we take externally generated
AccessKit nodes, such as those generated by Parley, into account.

masonry/src/contexts.rs

@@ -132,7 +132,6 @@ pub struct AccessCtx<'a> {
     pub(crate) widget_children: ArenaMutChildren<'a, Box<dyn Widget>>,
     pub(crate) tree_update: &'a mut TreeUpdate,
     pub(crate) rebuild_all: bool,
-    pub(crate) scale_factor: f64,
 }
 
 // --- MARK: GETTERS ---
@@ -1265,7 +1264,6 @@ impl<'s> AccessCtx<'s> {
             global_state: self.global_state,
             tree_update: self.tree_update,
             rebuild_all: self.rebuild_all,
-            scale_factor: self.scale_factor,
         };
         RawWrapper {
             ctx: child_ctx,

masonry/src/passes/accessibility.rs

@@ -19,7 +19,7 @@ fn build_accessibility_tree(
     mut widget: ArenaMut<'_, Box<dyn Widget>>,
     mut state: ArenaMut<'_, WidgetState>,
     rebuild_all: bool,
-    scale_factor: f64,
+    scale_factor: Option<f64>,
 ) {
     let _span = enter_span_if(
         global_state.trace.access,
@@ -49,10 +49,12 @@ fn build_accessibility_tree(
             widget_children: widget.children.reborrow_mut(),
             tree_update,
             rebuild_all,
-            scale_factor,
         };
         let mut node = build_access_node(widget.item, &mut ctx);
         widget.item.accessibility(&mut ctx, &mut node);
+        if let Some(scale_factor) = scale_factor {
+            node.set_transform(accesskit::Affine::scale(scale_factor));
+        }
 
         let id: NodeId = ctx.widget_state.id.into();
         if ctx.global_state.trace.access {
@@ -79,7 +81,7 @@ fn build_accessibility_tree(
                 widget,
                 state.reborrow_mut(),
                 rebuild_all,
-                scale_factor,
+                None,
             );
             parent_state.merge_up(state.item);
         },
@@ -89,10 +91,7 @@ fn build_accessibility_tree(
 // --- MARK: BUILD NODE ---
 fn build_access_node(widget: &mut dyn Widget, ctx: &mut AccessCtx) -> Node {
     let mut node = Node::new(widget.accessibility_role());
-    node.set_bounds(to_accesskit_rect(
-        ctx.widget_state.window_layout_rect(),
-        ctx.scale_factor,
-    ));
+    node.set_bounds(to_accesskit_rect(ctx.widget_state.window_layout_rect()));
 
     node.set_children(
         widget
@@ -124,9 +123,8 @@ fn build_access_node(widget: &mut dyn Widget, ctx: &mut AccessCtx) -> Node {
     node
 }
 
-fn to_accesskit_rect(r: Rect, scale_factor: f64) -> accesskit::Rect {
-    let sr = r.scale_from_origin(scale_factor);
-    accesskit::Rect::new(sr.x0, sr.y0, sr.x1, sr.y1)
+fn to_accesskit_rect(r: Rect) -> accesskit::Rect {
+    accesskit::Rect::new(r.x0, r.y0, r.x1, r.y1)
 }
 
 // --- MARK: ROOT ---
@@ -172,7 +170,7 @@ pub(crate) fn run_accessibility_pass(root: &mut RenderRoot, scale_factor: f64) -
         root_widget,
         root_state,
         root.rebuild_access_tree,
-        scale_factor,
+        Some(scale_factor),
     );
     root.rebuild_access_tree = false;