Report egui::Window contents as children to accesskit (#5240)

Previously, all widgets would be listed in accesskit as children of the
toplevel window.
With this change, they will be reported as child of the `egui::Window`
they are in, Which should increase parseability of the ui for
screenreaders and integration tests.

Added an accesskit test to check that it is indeed working.

Co-authored-by: Wybe Westra <w.westra@kwantcontrols.nl>

crates/egui/src/containers/area.rs

@@ -569,6 +569,14 @@ impl Prepared {
         ui
     }
 
+    pub(crate) fn with_widget_info(&self, make_info: impl Fn() -> crate::WidgetInfo) {
+        self.move_response.widget_info(make_info);
+    }
+
+    pub(crate) fn id(&self) -> Id {
+        self.move_response.id
+    }
+
     #[allow(clippy::needless_pass_by_value)] // intentional to swallow up `content_ui`.
     pub(crate) fn end(self, ctx: &Context, content_ui: Ui) -> Response {
         let Self {

crates/egui/src/containers/collapsing_header.rs

@@ -87,6 +87,14 @@ impl CollapsingState {
     ) -> Response {
         let (_id, rect) = ui.allocate_space(button_size);
         let response = ui.interact(rect, self.id, Sense::click());
+        response.widget_info(|| {
+            WidgetInfo::labeled(
+                WidgetType::Button,
+                ui.is_enabled(),
+                if self.is_open() { "Hide" } else { "Show" },
+            )
+        });
+
         if response.clicked() {
             self.toggle(ui);
         }

crates/egui/src/containers/window.rs

@@ -5,7 +5,7 @@ use std::sync::Arc;
 use crate::collapsing_header::CollapsingState;
 use crate::{
     Align, Align2, Context, CursorIcon, Id, InnerResponse, LayerId, NumExt, Order, Response, Sense,
-    TextStyle, Ui, UiKind, Vec2b, WidgetRect, WidgetText,
+    TextStyle, Ui, UiKind, Vec2b, WidgetInfo, WidgetRect, WidgetText, WidgetType,
 };
 use epaint::{emath, pos2, vec2, Galley, Pos2, Rect, RectShape, Rounding, Shape, Stroke, Vec2};
 
@@ -466,6 +466,8 @@ impl<'open> Window<'open> {
         let on_top = Some(area_layer_id) == ctx.top_layer_id();
         let mut area = area.begin(ctx);
 
+        area.with_widget_info(|| WidgetInfo::labeled(WidgetType::Window, true, title.text()));
+
         // Calculate roughly how much larger the window size is compared to the inner rect
         let (title_bar_height, title_content_spacing) = if with_title_bar {
             let style = ctx.style();
@@ -489,8 +491,9 @@ impl<'open> Window<'open> {
 
         // First check for resize to avoid frame delay:
         let last_frame_outer_rect = area.state().rect();
-        let resize_interaction =
-            resize_interaction(ctx, possible, area_layer_id, last_frame_outer_rect);
+        let resize_interaction = ctx.with_accessibility_parent(area.id(), || {
+            resize_interaction(ctx, possible, area_layer_id, last_frame_outer_rect)
+        });
 
         let margins = window_frame.outer_margin.sum()
             + window_frame.inner_margin.sum()
@@ -514,6 +517,7 @@ impl<'open> Window<'open> {
         }
 
         let content_inner = {
+            ctx.with_accessibility_parent(area.id(), || {
                 // BEGIN FRAME --------------------------------
                 let frame_stroke = window_frame.stroke;
                 let mut frame = window_frame.begin(&mut area_content_ui);
@@ -615,6 +619,7 @@ impl<'open> Window<'open> {
                 paint_frame_interaction(&area_content_ui, outer_rect, resize_interaction);
 
                 content_inner
+            })
         };
 
         let full_response = area.end(ctx, area_content_ui);
@@ -1192,6 +1197,9 @@ impl TitleBar {
 fn close_button(ui: &mut Ui, rect: Rect) -> Response {
     let close_id = ui.auto_id_with("window_close_button");
     let response = ui.interact(rect, close_id, Sense::click());
+    response
+        .widget_info(|| WidgetInfo::labeled(WidgetType::Button, ui.is_enabled(), "Close window"));
+
     ui.expand_to_include_rect(response.rect);
 
     let visuals = ui.style().interact(&response);

crates/egui/src/data/output.rs

@@ -675,6 +675,7 @@ impl WidgetInfo {
             WidgetType::ImageButton => "image button",
             WidgetType::CollapsingHeader => "collapsing header",
             WidgetType::ProgressIndicator => "progress indicator",
+            WidgetType::Window => "window",
             WidgetType::Label | WidgetType::Other => "",
         };
 

crates/egui/src/lib.rs

@@ -656,6 +656,8 @@ pub enum WidgetType {
 
     ProgressIndicator,
 
+    Window,
+
     /// If you cannot fit any of the above slots.
     ///
     /// If this is something you think should be added, file an issue.

crates/egui/src/response.rs

@@ -1032,6 +1032,7 @@ impl Response {
             WidgetType::DragValue => Role::SpinButton,
             WidgetType::ColorButton => Role::ColorWell,
             WidgetType::ProgressIndicator => Role::ProgressIndicator,
+            WidgetType::Window => Role::Window,
             WidgetType::Other => Role::Unknown,
         });
         if !info.enabled {

crates/egui/tests/accesskit.rs

@@ -1,8 +1,8 @@
 //! Tests the accesskit accessibility output of egui.
 #![cfg(feature = "accesskit")]
 
-use accesskit::{Role, TreeUpdate};
-use egui::{CentralPanel, Context, RawInput};
+use accesskit::{NodeId, Role, TreeUpdate};
+use egui::{CentralPanel, Context, RawInput, Window};
 
 /// Baseline test that asserts there are no spurious nodes in the
 /// accesskit output when the ui is empty.
@@ -130,8 +130,30 @@ fn multiple_disabled_widgets() {
     );
 }
 
+#[test]
+fn window_children() {
+    let output = accesskit_output_single_egui_frame(|ctx| {
+        let mut open = true;
+        Window::new("test window")
+            .open(&mut open)
+            .resizable(false)
+            .show(ctx, |ui| {
+                let _ = ui.button("A button");
+            });
+    });
+
+    let root = output.tree.as_ref().map(|tree| tree.root).unwrap();
+
+    let window_id = assert_window_exists(&output, "test window", root);
+    assert_button_exists(&output, "A button", window_id);
+    assert_button_exists(&output, "Close window", window_id);
+    assert_button_exists(&output, "Hide", window_id);
+}
+
 fn accesskit_output_single_egui_frame(run_ui: impl FnMut(&Context)) -> TreeUpdate {
     let ctx = Context::default();
+    // Disable animations, so we do not need to wait for animations to end to see the result.
+    ctx.style_mut(|style| style.animation_time = 0.0);
     ctx.enable_accesskit();
 
     let output = ctx.run(RawInput::default(), run_ui);
@@ -141,3 +163,45 @@ fn accesskit_output_single_egui_frame(run_ui: impl FnMut(&Context)) -> TreeUpdat
         .accesskit_update
         .expect("Missing accesskit update")
 }
+
+#[track_caller]
+fn assert_button_exists(tree: &TreeUpdate, name: &str, parent: NodeId) {
+    let (node_id, _) = tree
+        .nodes
+        .iter()
+        .find(|(_, node)| {
+            !node.is_hidden() && node.role() == Role::Button && node.name() == Some(name)
+        })
+        .expect("No visible button with that name exists.");
+
+    assert_parent_child(tree, parent, *node_id);
+}
+
+#[track_caller]
+fn assert_window_exists(tree: &TreeUpdate, title: &str, parent: NodeId) -> NodeId {
+    let (node_id, _) = tree
+        .nodes
+        .iter()
+        .find(|(_, node)| {
+            !node.is_hidden() && node.role() == Role::Window && node.name() == Some(title)
+        })
+        .expect("No visible window with that title exists.");
+
+    assert_parent_child(tree, parent, *node_id);
+
+    *node_id
+}
+
+#[track_caller]
+fn assert_parent_child(tree: &TreeUpdate, parent: NodeId, child: NodeId) {
+    let (_, parent) = tree
+        .nodes
+        .iter()
+        .find(|(id, _)| id == &parent)
+        .expect("Parent does not exist.");
+
+    assert!(
+        parent.children().contains(&child),
+        "Node is not a child of the given parent."
+    );
+}