From 8581f607f8c3de042b470d79762cf7346e6eca79 Mon Sep 17 00:00:00 2001
From: ickshonpe <david.curthoys@googlemail.com>
Date: Mon, 8 May 2023 21:49:55 +0100
Subject: [PATCH] Replace remaining uses of `&T, Changed<T>` with `Ref` in UI
 system queries (#8567)

# Objective

Replace `Query<&T, Changed<T>>` style queries with the more efficient
`Query<Ref<T>>` form in two of the UI systems.

---

## Changelog

Replaced use of `Changed` with `Ref` in queries in the
`ui_layout_system` and `calc_bounds` UI systems.
---
 crates/bevy_ui/src/accessibility.rs | 32 ++++++++++++++---------------
 crates/bevy_ui/src/layout/mod.rs    |  8 +++++---
 2 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/crates/bevy_ui/src/accessibility.rs b/crates/bevy_ui/src/accessibility.rs
index 42b2137e9c..f54d2efff3 100644
--- a/crates/bevy_ui/src/accessibility.rs
+++ b/crates/bevy_ui/src/accessibility.rs
@@ -8,9 +8,10 @@ use bevy_a11y::{
 };
 use bevy_app::{App, Plugin, Update};
 use bevy_ecs::{
-    prelude::Entity,
-    query::{Changed, Or, Without},
+    prelude::{DetectChanges, Entity},
+    query::{Changed, Without},
     system::{Commands, Query},
+    world::Ref,
 };
 use bevy_hierarchy::Children;
 use bevy_render::prelude::Camera;
@@ -34,23 +35,22 @@ fn calc_name(texts: &Query<&Text>, children: &Children) -> Option<Box<str>> {
 
 fn calc_bounds(
     camera: Query<(&Camera, &GlobalTransform)>,
-    mut nodes: Query<
-        (&mut AccessibilityNode, &Node, &GlobalTransform),
-        Or<(Changed<Node>, Changed<GlobalTransform>)>,
-    >,
+    mut nodes: Query<(&mut AccessibilityNode, Ref<Node>, Ref<GlobalTransform>)>,
 ) {
     if let Ok((camera, camera_transform)) = camera.get_single() {
         for (mut accessible, node, transform) in &mut nodes {
-            if let Some(translation) =
-                camera.world_to_viewport(camera_transform, transform.translation())
-            {
-                let bounds = Rect::new(
-                    translation.x.into(),
-                    translation.y.into(),
-                    (translation.x + node.calculated_size.x).into(),
-                    (translation.y + node.calculated_size.y).into(),
-                );
-                accessible.set_bounds(bounds);
+            if node.is_changed() || transform.is_changed() {
+                if let Some(translation) =
+                    camera.world_to_viewport(camera_transform, transform.translation())
+                {
+                    let bounds = Rect::new(
+                        translation.x.into(),
+                        translation.y.into(),
+                        (translation.x + node.calculated_size.x).into(),
+                        (translation.y + node.calculated_size.y).into(),
+                    );
+                    accessible.set_bounds(bounds);
+                }
             }
         }
     }
diff --git a/crates/bevy_ui/src/layout/mod.rs b/crates/bevy_ui/src/layout/mod.rs
index b1556515eb..14da00866d 100644
--- a/crates/bevy_ui/src/layout/mod.rs
+++ b/crates/bevy_ui/src/layout/mod.rs
@@ -6,7 +6,7 @@ use bevy_ecs::{
     change_detection::DetectChanges,
     entity::Entity,
     event::EventReader,
-    query::{Changed, With, Without},
+    query::{With, Without},
     removal_detection::RemovedComponents,
     system::{Query, Res, ResMut, Resource},
     world::Ref,
@@ -222,7 +222,7 @@ pub fn ui_layout_system(
     root_node_query: Query<Entity, (With<Node>, Without<Parent>)>,
     style_query: Query<(Entity, Ref<Style>), With<Node>>,
     mut measure_query: Query<(Entity, &mut ContentSize)>,
-    children_query: Query<(Entity, &Children), (With<Node>, Changed<Children>)>,
+    children_query: Query<(Entity, Ref<Children>), With<Node>>,
     mut removed_children: RemovedComponents<Children>,
     mut removed_content_sizes: RemovedComponents<ContentSize>,
     mut node_transform_query: Query<(Entity, &mut Node, &mut Transform, Option<&Parent>)>,
@@ -293,7 +293,9 @@ pub fn ui_layout_system(
         ui_surface.try_remove_children(entity);
     }
     for (entity, children) in &children_query {
-        ui_surface.update_children(entity, children);
+        if children.is_changed() {
+            ui_surface.update_children(entity, &children);
+        }
     }
 
     // compute layouts