Resolve UI outlines using the correct target's viewport size (#14947)

# Objective
`resolve_outlines_system` wasn't updated when multi-window support was
added and it always uses the size of the primary window when resolving
viewport coords, regardless of the layout's camera target.

Fixes #14945

## Solution

It's awkward to get the viewport size of the target for an individual
node without walking the tree or adding extra fields to `Node`, so I
removed `resolve_outlines_system` and instead the outline values are
updated in `ui_layout_system`.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>

crates/bevy_ui/src/accessibility.rs

@@ -154,7 +154,6 @@ impl Plugin for AccessibilityPlugin {
                     .after(bevy_transform::TransformSystem::TransformPropagate)
                     .after(CameraUpdateSystem)
                     // the listed systems do not affect calculated size
-                    .ambiguous_with(crate::resolve_outlines_system)
                     .ambiguous_with(crate::ui_stack_system),
                 button_changed,
                 image_changed,

crates/bevy_ui/src/layout/mod.rs

@@ -94,7 +94,7 @@ pub fn ui_layout_system(
     children_query: Query<(Entity, Ref<Children>), With<Node>>,
     just_children_query: Query<&Children>,
     mut removed_components: UiLayoutSystemRemovedComponentParam,
-    mut node_transform_query: Query<(&mut Node, &mut Transform)>,
+    mut node_transform_query: Query<(&mut Node, &mut Transform, Option<&Outline>)>,
     #[cfg(feature = "bevy_text")] mut buffer_query: Query<&mut CosmicBuffer>,
     #[cfg(feature = "bevy_text")] mut text_pipeline: ResMut<TextPipeline>,
 ) {
@@ -247,6 +247,7 @@ pub fn ui_layout_system(
             update_uinode_geometry_recursive(
                 *root,
                 &ui_surface,
+                None,
                 &mut node_transform_query,
                 &just_children_query,
                 inverse_target_scale_factor,
@@ -259,13 +260,14 @@ pub fn ui_layout_system(
     fn update_uinode_geometry_recursive(
         entity: Entity,
         ui_surface: &UiSurface,
-        node_transform_query: &mut Query<(&mut Node, &mut Transform)>,
+        root_size: Option<Vec2>,
+        node_transform_query: &mut Query<(&mut Node, &mut Transform, Option<&Outline>)>,
         children_query: &Query<&Children>,
         inverse_target_scale_factor: f32,
         parent_size: Vec2,
         mut absolute_location: Vec2,
     ) {
-        if let Ok((mut node, mut transform)) = node_transform_query.get_mut(entity) {
+        if let Ok((mut node, mut transform, outline)) = node_transform_query.get_mut(entity) {
             let Ok(layout) = ui_surface.get_layout(entity) else {
                 return;
             };
@@ -287,39 +289,11 @@ pub fn ui_layout_system(
                 node.calculated_size = rounded_size;
                 node.unrounded_size = layout_size;
             }
-            if transform.translation.truncate() != rounded_location {
-                transform.translation = rounded_location.extend(0.);
-            }
-            if let Ok(children) = children_query.get(entity) {
-                for &child_uinode in children {
-                    update_uinode_geometry_recursive(
-                        child_uinode,
-                        ui_surface,
-                        node_transform_query,
-                        children_query,
-                        inverse_target_scale_factor,
-                        rounded_size,
-                        absolute_location,
-                    );
-                }
-            }
-        }
-    }
-}
 
-/// Resolve and update the widths of Node outlines
+            let viewport_size = root_size.unwrap_or(node.calculated_size);
-pub fn resolve_outlines_system(
-    primary_window: Query<&Window, With<PrimaryWindow>>,
-    ui_scale: Res<UiScale>,
-    mut outlines_query: Query<(&Outline, &mut Node)>,
-) {
-    let viewport_size = primary_window
-        .get_single()
-        .map(Window::size)
-        .unwrap_or(Vec2::ZERO)
-        / ui_scale.0;
 
-    for (outline, mut node) in outlines_query.iter_mut() {
+            if let Some(outline) = outline {
+                // don't trigger change detection when only outlines are changed
                 let node = node.bypass_change_detection();
                 node.outline_width = outline
                     .width
@@ -333,6 +307,27 @@ pub fn resolve_outlines_system(
                     .unwrap_or(0.)
                     .max(0.);
             }
+
+            if transform.translation.truncate() != rounded_location {
+                transform.translation = rounded_location.extend(0.);
+            }
+
+            if let Ok(children) = children_query.get(entity) {
+                for &child_uinode in children {
+                    update_uinode_geometry_recursive(
+                        child_uinode,
+                        ui_surface,
+                        Some(viewport_size),
+                        node_transform_query,
+                        children_query,
+                        inverse_target_scale_factor,
+                        rounded_size,
+                        absolute_location,
+                    );
+                }
+            }
+        }
+    }
 }
 
 #[inline]

crates/bevy_ui/src/lib.rs

@@ -92,10 +92,6 @@ pub enum UiSystem {
     ///
     /// Runs in [`PostUpdate`].
     Stack,
-    /// After this label, node outline widths have been updated.
-    ///
-    /// Runs in [`PostUpdate`].
-    Outlines,
 }
 
 /// The current scale of the UI.
@@ -153,7 +149,7 @@ impl Plugin for UiPlugin {
                     CameraUpdateSystem,
                     UiSystem::Prepare.before(UiSystem::Stack),
                     UiSystem::Layout,
-                    (UiSystem::PostLayout, UiSystem::Outlines),
+                    UiSystem::PostLayout,
                 )
                     .chain(),
             )
@@ -170,16 +166,10 @@ impl Plugin for UiPlugin {
                 ui_layout_system
                     .in_set(UiSystem::Layout)
                     .before(TransformSystem::TransformPropagate),
-                resolve_outlines_system
-                    .in_set(UiSystem::Outlines)
-                    // clipping doesn't care about outlines
-                    .ambiguous_with(update_clipping_system)
-                    .in_set(AmbiguousWithTextSystem),
                 ui_stack_system
                     .in_set(UiSystem::Stack)
                     // the systems don't care about stack index
                     .ambiguous_with(update_clipping_system)
-                    .ambiguous_with(resolve_outlines_system)
                     .ambiguous_with(ui_layout_system)
                     .in_set(AmbiguousWithTextSystem),
                 update_clipping_system.after(TransformSystem::TransformPropagate),

crates/bevy_ui/src/ui_node.rs

@@ -35,10 +35,14 @@ pub struct Node {
     pub(crate) calculated_size: Vec2,
     /// The width of this node's outline.
     /// If this value is `Auto`, negative or `0.` then no outline will be rendered.
+    /// Outline updates bypass change detection.
     ///
-    /// Automatically calculated by [`super::layout::resolve_outlines_system`].
+    /// Automatically calculated by [`super::layout::ui_layout_system`].
     pub(crate) outline_width: f32,
     /// The amount of space between the outline and the edge of the node.
+    /// Outline updates bypass change detection.
+    ///
+    /// Automatically calculated by [`super::layout::ui_layout_system`].
     pub(crate) outline_offset: f32,
     /// The unrounded size of the node as width and height in logical pixels.
     ///

tests/ecs/ambiguity_detection.rs

@@ -33,7 +33,7 @@ fn main() {
         // Over time, we are working to reduce the number: your PR should not increase it.
         // If you decrease this by fixing an ambiguity, reduce the number to prevent regressions.
         // See https://github.com/bevyengine/bevy/issues/7386 for progress.
-        48,
+        46,
         "Main app has unexpected ambiguities among the following schedules: \n{:#?}.",
         main_app_ambiguities,
     );