use super::*;
const DEV_OVERLAY_PADDING: f32 = 8.0;
const DEV_OVERLAY_FONT_SIZE: f32 = 14.0;
const DEV_OVERLAY_CHAR_WIDTH: f32 = 7.0;
const DEV_OVERLAY_REFRESH_INTERVAL: std::time::Duration = std::time::Duration::from_millis(250);
const DEFAULT_FRAME_STAGE_TELEMETRY_THRESHOLD_MS: f64 = 4.0;
#[derive(Copy, Clone)]
enum DispatchInvalidationKind {
Pointer,
Focus,
}
fn frame_stage_telemetry_threshold_ms() -> Option<f64> {
static THRESHOLD_MS: std::sync::OnceLock<Option<f64>> = std::sync::OnceLock::new();
*THRESHOLD_MS.get_or_init(|| {
let explicit = std::env::var("CRANPOSE_FRAME_STAGE_TELEMETRY_MS")
.ok()
.and_then(|value| value.parse::<f64>().ok())
.filter(|value| value.is_finite() && *value >= 0.0);
explicit.or_else(|| {
std::env::var_os("CRANPOSE_FRAME_STAGE_TELEMETRY")
.is_some()
.then_some(DEFAULT_FRAME_STAGE_TELEMETRY_THRESHOLD_MS)
})
})
}
fn log_frame_stage_telemetry(
frame_start: Instant,
after_initial_layout: Instant,
after_layout: Instant,
after_dispatch: Instant,
after_render: Instant,
) {
let Some(threshold_ms) = frame_stage_telemetry_threshold_ms() else {
return;
};
let total_ms = after_render.duration_since(frame_start).as_secs_f64() * 1000.0;
if total_ms < threshold_ms {
return;
}
let layout_ms = after_layout.duration_since(frame_start).as_secs_f64() * 1000.0;
let initial_layout_ms = after_initial_layout
.duration_since(frame_start)
.as_secs_f64()
* 1000.0;
let post_layout_ms = after_layout
.duration_since(after_initial_layout)
.as_secs_f64()
* 1000.0;
let dispatch_ms = after_dispatch.duration_since(after_layout).as_secs_f64() * 1000.0;
let scene_ms = after_render.duration_since(after_dispatch).as_secs_f64() * 1000.0;
log::warn!(
"[frame-stage-telemetry] total_ms={total_ms:.2} layout_ms={layout_ms:.2} initial_layout_ms={initial_layout_ms:.2} post_layout_ms={post_layout_ms:.2} dispatch_ms={dispatch_ms:.2} scene_ms={scene_ms:.2}",
);
}
fn render_phase_dirty_diagnostics_enabled() -> bool {
static ENABLED: std::sync::OnceLock<bool> = std::sync::OnceLock::new();
*ENABLED.get_or_init(|| std::env::var_os("CRANPOSE_RENDER_PHASE_DIRTY_DIAG").is_some())
}
struct RenderPhaseDirtyDiagnostics<'a> {
render_dirty: bool,
pointer_dirty: bool,
scene_dirty: bool,
draw_repass_pending: bool,
draw_dirty_nodes: usize,
layout_dirty_nodes: usize,
partial_dirty_nodes: usize,
dirty_node_ids: Option<String>,
render_only_dirty: bool,
recomposed_this_frame: bool,
path: &'a str,
}
fn log_render_phase_dirty_diagnostics(diagnostics: RenderPhaseDirtyDiagnostics<'_>) {
if !render_phase_dirty_diagnostics_enabled() {
return;
}
let RenderPhaseDirtyDiagnostics {
render_dirty,
pointer_dirty,
scene_dirty,
draw_repass_pending,
draw_dirty_nodes,
layout_dirty_nodes,
partial_dirty_nodes,
dirty_node_ids,
render_only_dirty,
recomposed_this_frame,
path,
} = diagnostics;
if let Some(dirty_node_ids) = dirty_node_ids {
log::warn!(
"[render-phase-dirty] path={path} render_dirty={render_dirty} pointer_dirty={pointer_dirty} scene_dirty={scene_dirty} draw_repass_pending={draw_repass_pending} draw_dirty_nodes={draw_dirty_nodes} layout_dirty_nodes={layout_dirty_nodes} partial_dirty_nodes={partial_dirty_nodes} render_only_dirty={render_only_dirty} recomposed_this_frame={recomposed_this_frame} ids={dirty_node_ids}",
);
} else {
log::warn!(
"[render-phase-dirty] path={path} render_dirty={render_dirty} pointer_dirty={pointer_dirty} scene_dirty={scene_dirty} draw_repass_pending={draw_repass_pending} draw_dirty_nodes={draw_dirty_nodes} layout_dirty_nodes={layout_dirty_nodes} partial_dirty_nodes={partial_dirty_nodes} render_only_dirty={render_only_dirty} recomposed_this_frame={recomposed_this_frame}",
);
}
}
impl<R> AppShell<R>
where
R: Renderer,
R::Error: Debug,
{
pub fn set_semantics_enabled(&mut self, enabled: bool) {
if self.semantics_enabled == enabled {
return;
}
self.semantics_enabled = enabled;
if enabled {
self.request_forced_layout_pass();
self.mark_dirty();
} else {
self.semantics_tree = None;
}
}
pub(crate) fn process_frame(&mut self) -> FrameUpdateResult {
let app_context = Rc::clone(&self.app_context);
app_context.enter(|| self.process_frame_in_context(false))
}
pub(crate) fn process_frame_in_context(
&mut self,
recomposed_before_frame: bool,
) -> FrameUpdateResult {
let frame_start = Instant::now();
self.run_layout_phase();
let after_initial_layout = Instant::now();
let recomposed_this_frame = recomposed_before_frame || self.run_post_layout_recomposition();
let after_layout = Instant::now();
self.run_dispatch_queues();
let after_dispatch = Instant::now();
clear_transient_scroll_motion_contexts();
let result = self.run_render_phase_with_recomposition_state(recomposed_this_frame);
let after_render = Instant::now();
log_frame_stage_telemetry(
frame_start,
after_initial_layout,
after_layout,
after_dispatch,
after_render,
);
result
}
pub(crate) fn run_layout_phase(&mut self) {
let app_context = Rc::clone(&self.app_context);
app_context.enter(|| self.run_layout_phase_in_context());
}
fn run_layout_phase_in_context(&mut self) {
let has_scoped_repasses = cranpose_ui::has_pending_layout_repasses();
let scoped_layout_nodes = if has_scoped_repasses {
cranpose_ui::pending_layout_repass_nodes_snapshot()
} else {
Vec::new()
};
let invalidation_requested = take_layout_invalidation();
let global_layout_invalidation = invalidation_requested && !has_scoped_repasses;
let force_layout_pass = self.force_layout_pass;
if invalidation_requested && !has_scoped_repasses {
cranpose_ui::layout::invalidate_all_layout_caches();
if let Some(root) = self.composition.root() {
let mut applier = self.composition.applier_mut();
match applier.with_node::<LayoutNode, _>(root, |node| {
node.mark_needs_measure();
node.mark_needs_layout();
}) {
Ok(()) | Err(NodeError::Missing { .. }) => {}
Err(NodeError::TypeMismatch { .. }) => {
let _ = applier.with_node::<SubcomposeLayoutNode, _>(root, |node| {
node.mark_needs_measure();
node.mark_needs_layout_flag();
});
}
Err(_) => {}
}
}
self.request_forced_layout_pass();
} else if invalidation_requested || has_scoped_repasses {
self.request_layout_pass();
}
if !self.layout_requested {
return;
}
let viewport_size = Size {
width: self.viewport.0,
height: self.viewport.1,
};
if let Some(root) = self.composition.root() {
let handle = self.composition.runtime_handle();
let mut applier = self.composition.applier_mut();
applier.set_runtime_handle(handle);
let tree_needs_layout_check = cranpose_ui::tree_needs_layout(&mut *applier, root)
.unwrap_or_else(|err| {
log::warn!(
"Cannot check layout dirty status for root #{}: {}",
root,
err
);
true });
let needs_layout =
self.force_layout_pass || has_scoped_repasses || tree_needs_layout_check;
if !needs_layout {
log::trace!("Skipping layout: tree is clean");
self.layout_requested = false;
self.force_layout_pass = false;
applier.clear_runtime_handle();
return;
}
self.layout_requested = false;
self.force_layout_pass = false;
match cranpose_ui::measure_layout_with_options(
&mut applier,
root,
viewport_size,
MeasureLayoutOptions {
collect_semantics: false,
build_layout_tree: false,
},
) {
Ok(_measurements) => {
self.layout_tree = None;
if self.semantics_enabled {
self.semantics_tree = None;
}
if has_scoped_repasses
&& !global_layout_invalidation
&& !force_layout_pass
&& !scoped_layout_nodes.is_empty()
{
self.scoped_layout_scene_nodes = scoped_layout_nodes;
} else {
self.scoped_layout_scene_nodes.clear();
}
self.scene_dirty = true;
}
Err(err) => {
log::error!("failed to compute layout: {err}");
self.layout_tree = None;
self.semantics_tree = None;
self.scoped_layout_scene_nodes.clear();
self.scene_dirty = true;
}
}
applier.clear_runtime_handle();
} else {
self.layout_tree = None;
self.semantics_tree = None;
self.scoped_layout_scene_nodes.clear();
self.scene_dirty = true;
self.layout_requested = false;
self.force_layout_pass = false;
}
}
fn run_post_layout_recomposition(&mut self) -> bool {
if !self.composition.should_render() {
return false;
}
let Some(root_key) = self.composition.root_key() else {
return false;
};
match self.composition.reconcile(root_key, &mut *self.content) {
Ok(changed) => {
if !changed {
return false;
}
self.fps_monitor.record_recomposition();
if self.composition_tree_needs_layout() {
self.request_layout_pass();
self.run_layout_phase_in_context();
}
request_render_invalidation();
true
}
Err(NodeError::Missing { id }) => {
log::debug!(
"Post-layout recomposition skipped: node {} no longer exists",
id
);
self.request_layout_pass();
request_render_invalidation();
true
}
Err(err) => {
log::error!("post-layout recomposition failed: {err}");
self.request_layout_pass();
request_render_invalidation();
true
}
}
}
fn run_dispatch_queues(&mut self) {
if has_pending_pointer_repasses() {
let mut applier = self.composition.applier_mut();
process_pointer_repasses(|node_id| {
match clear_dispatch_invalidation(
&mut applier,
node_id,
DispatchInvalidationKind::Pointer,
) {
Ok(true) => {
log::trace!("Cleared pointer repass flag for node #{}", node_id);
}
Ok(false) => {}
Err(err) => {
log::debug!(
"Could not process pointer repass for node #{}: {}",
node_id,
err
);
}
}
});
}
if has_pending_focus_invalidations() {
let mut applier = self.composition.applier_mut();
process_focus_invalidations(|node_id| {
match clear_dispatch_invalidation(
&mut applier,
node_id,
DispatchInvalidationKind::Focus,
) {
Ok(true) => {
log::trace!("Cleared focus sync flag for node #{}", node_id);
}
Ok(false) => {}
Err(err) => {
log::debug!(
"Could not process focus invalidation for node #{}: {}",
node_id,
err
);
}
}
});
}
}
fn refresh_draw_repasses(&mut self) -> Vec<NodeId> {
let dirty_nodes = take_draw_repass_nodes();
if dirty_nodes.is_empty() {
return dirty_nodes;
}
self.refresh_draw_nodes(dirty_nodes)
}
fn refresh_retained_redraw_nodes(&mut self) -> Vec<NodeId> {
let Some(root) = self.composition.root() else {
return Vec::new();
};
let mut dirty_nodes = Vec::new();
{
let mut applier = self.composition.applier_mut();
collect_retained_redraw_nodes(&mut applier, root, &mut dirty_nodes);
}
if dirty_nodes.is_empty() {
return dirty_nodes;
}
self.refresh_draw_nodes(dirty_nodes)
}
fn refresh_draw_nodes(&mut self, dirty_nodes: Vec<NodeId>) -> Vec<NodeId> {
let Some(layout_tree) = self.layout_tree.as_mut() else {
return dirty_nodes;
};
let dirty_set: HashSet<NodeId> = dirty_nodes.into_iter().collect();
let mut applier = self.composition.applier_mut();
let refresh_scope = build_draw_refresh_scope(&mut applier, &dirty_set);
refresh_layout_box_data(
&mut applier,
layout_tree.root_mut(),
&refresh_scope,
&dirty_set,
);
dirty_set.into_iter().collect()
}
#[cfg(test)]
pub(crate) fn run_render_phase(&mut self) -> FrameUpdateResult {
let app_context = Rc::clone(&self.app_context);
app_context.enter(|| self.run_render_phase_in_context(false))
}
fn run_render_phase_with_recomposition_state(
&mut self,
recomposed_this_frame: bool,
) -> FrameUpdateResult {
let app_context = Rc::clone(&self.app_context);
app_context.enter(|| self.run_render_phase_in_context(recomposed_this_frame))
}
fn run_render_phase_in_context(&mut self, recomposed_this_frame: bool) -> FrameUpdateResult {
let render_dirty = take_render_invalidation();
let pointer_dirty = take_pointer_invalidation();
take_focus_invalidation();
let draw_repass_pending = cranpose_ui::has_pending_draw_repasses();
let mut draw_dirty_nodes = self.refresh_draw_repasses();
if render_dirty && !draw_repass_pending && draw_dirty_nodes.is_empty() {
draw_dirty_nodes = self.refresh_retained_redraw_nodes();
}
let layout_dirty_nodes = std::mem::take(&mut self.scoped_layout_scene_nodes);
let mut partial_dirty_nodes = draw_dirty_nodes.clone();
partial_dirty_nodes.extend(layout_dirty_nodes.iter().copied());
partial_dirty_nodes.sort_unstable();
partial_dirty_nodes.dedup();
let draw_dirty_node_count = draw_dirty_nodes.len();
let layout_dirty_node_count = layout_dirty_nodes.len();
let partial_dirty_node_count = partial_dirty_nodes.len();
let cursor_blink_dirty = cranpose_ui::tick_cursor_blink();
let render_only_dirty =
(render_dirty && partial_dirty_nodes.is_empty() && !draw_repass_pending)
|| cursor_blink_dirty;
let scene_dirty = self.scene_dirty;
let draw_only_partial_dirty = !draw_dirty_nodes.is_empty()
&& layout_dirty_nodes.is_empty()
&& !pointer_dirty
&& !recomposed_this_frame;
let scoped_scene_dirty = scene_dirty && !layout_dirty_nodes.is_empty();
let full_scene_dirty = scene_dirty && !scoped_scene_dirty && !draw_only_partial_dirty;
let partial_scene_dirty = !partial_dirty_nodes.is_empty();
let needs_scene_rebuild = full_scene_dirty
|| scoped_scene_dirty
|| partial_scene_dirty
|| draw_repass_pending
|| render_only_dirty;
if !needs_scene_rebuild {
log_render_phase_dirty_diagnostics(RenderPhaseDirtyDiagnostics {
render_dirty,
pointer_dirty,
scene_dirty,
draw_repass_pending,
draw_dirty_nodes: draw_dirty_node_count,
layout_dirty_nodes: layout_dirty_node_count,
partial_dirty_nodes: partial_dirty_node_count,
dirty_node_ids: render_phase_dirty_diagnostics_enabled().then(|| {
format!(
"draw={:?} layout={:?} partial={:?}",
draw_dirty_nodes, layout_dirty_nodes, partial_dirty_nodes
)
}),
render_only_dirty,
recomposed_this_frame,
path: "skip",
});
self.scoped_layout_scene_nodes = layout_dirty_nodes;
return FrameUpdateResult::default();
}
self.scene_dirty = false;
let viewport_size = Size {
width: self.viewport.0,
height: self.viewport.1,
};
let visual_update_only =
draw_only_partial_dirty && !partial_dirty_nodes.is_empty() && !full_scene_dirty;
let structure_changed = !render_only_dirty && !visual_update_only;
if let Some(root) = self.composition.root() {
let mut applier = self.composition.applier_mut();
let use_partial_update =
!partial_dirty_nodes.is_empty() && !render_only_dirty && !full_scene_dirty;
let use_visual_update = use_partial_update && draw_only_partial_dirty;
log_render_phase_dirty_diagnostics(RenderPhaseDirtyDiagnostics {
render_dirty,
pointer_dirty,
scene_dirty,
draw_repass_pending,
draw_dirty_nodes: draw_dirty_node_count,
layout_dirty_nodes: layout_dirty_node_count,
partial_dirty_nodes: partial_dirty_node_count,
dirty_node_ids: render_phase_dirty_diagnostics_enabled().then(|| {
format!(
"draw={:?} layout={:?} partial={:?}",
draw_dirty_nodes, layout_dirty_nodes, partial_dirty_nodes
)
}),
render_only_dirty,
recomposed_this_frame,
path: if use_visual_update {
"visual-update"
} else if use_partial_update {
"update"
} else {
"rebuild"
},
});
let rebuild_result = if use_visual_update {
self.renderer.update_visual_scene_from_applier(
&mut applier,
root,
viewport_size,
&partial_dirty_nodes,
)
} else if use_partial_update {
self.renderer.update_scene_from_applier(
&mut applier,
root,
viewport_size,
&partial_dirty_nodes,
)
} else {
self.renderer
.rebuild_scene_from_applier(&mut applier, root, viewport_size)
};
if let Err(err) = rebuild_result {
log::error!("renderer rebuild failed: {err:?}");
self.renderer.scene_mut().clear();
}
} else {
self.renderer.scene_mut().clear();
}
if self.dev_options.fps_counter {
self.refresh_dev_overlay_text_for_frame_at(viewport_size, Instant::now());
let renderer = &mut self.renderer;
let text = self.dev_overlay_text.as_str();
renderer.draw_dev_overlay(text, viewport_size);
}
FrameUpdateResult {
visual_changed: true,
structure_changed,
}
}
fn refresh_dev_overlay_text_for_frame_at(&mut self, viewport_size: Size, now: Instant) {
if !self.dev_overlay_text_needs_refresh(viewport_size, now) {
return;
}
self.dev_overlay_text = self.build_dev_overlay_text(viewport_size);
self.dev_overlay_last_refresh = Some(now);
self.dev_overlay_viewport = Some(viewport_size);
}
fn dev_overlay_text_needs_refresh(&self, viewport_size: Size, now: Instant) -> bool {
if self.dev_overlay_text.is_empty() || self.dev_overlay_viewport != Some(viewport_size) {
return true;
}
self.dev_overlay_last_refresh
.map(|last| {
now.checked_duration_since(last).unwrap_or_default() >= DEV_OVERLAY_REFRESH_INTERVAL
})
.unwrap_or(true)
}
fn build_dev_overlay_text(&mut self, viewport_size: Size) -> String {
self.dev_overlay_controls.clear();
let stats = self.fps_monitor.stats();
let mut text = format!(
"{:.0} FPS | avg {:.1}ms | p95 {:.1}ms | max {:.1}ms | work {:.1}ms | {} recomp/s",
stats.fps,
stats.avg_ms,
stats.p95_ms,
stats.max_ms,
stats.work_avg_ms,
stats.recomps_per_second
);
if !self.dev_options.frame_pacing_controls {
return text;
}
text.push_str(" | ");
let mut controls = Vec::with_capacity(FramePacingMode::ALL.len());
for (index, mode) in FramePacingMode::ALL.into_iter().enumerate() {
if index > 0 {
text.push(' ');
}
let start = text.len();
if mode == self.dev_options.frame_pacing_mode {
text.push('[');
text.push_str(mode.label());
text.push(']');
} else {
text.push_str(mode.label());
}
controls.push((start, text.len(), mode));
}
let overlay_width = text.len() as f32 * DEV_OVERLAY_CHAR_WIDTH;
let overlay_x = (viewport_size.width - overlay_width - DEV_OVERLAY_PADDING * 2.0)
.max(DEV_OVERLAY_PADDING);
let overlay_y = DEV_OVERLAY_PADDING;
let text_x = overlay_x + DEV_OVERLAY_PADDING / 2.0;
let text_y = overlay_y + DEV_OVERLAY_PADDING / 4.0;
let text_height = DEV_OVERLAY_FONT_SIZE * 1.4;
self.dev_overlay_controls = controls
.into_iter()
.map(|(start, end, mode)| DevOverlayControl {
bounds: Rect {
x: text_x + start as f32 * DEV_OVERLAY_CHAR_WIDTH - 3.0,
y: text_y - 3.0,
width: (end - start) as f32 * DEV_OVERLAY_CHAR_WIDTH + 6.0,
height: text_height + 6.0,
},
mode,
})
.collect();
text
}
}
fn clear_dispatch_invalidation(
applier: &mut MemoryApplier,
node_id: NodeId,
invalidation: DispatchInvalidationKind,
) -> Result<bool, NodeError> {
match invalidation {
DispatchInvalidationKind::Pointer => {
match applier.with_node::<LayoutNode, _>(node_id, |node| {
let needs_pointer_pass = node.needs_pointer_pass();
if needs_pointer_pass {
node.clear_needs_pointer_pass();
}
needs_pointer_pass
}) {
Ok(cleared) => Ok(cleared),
Err(NodeError::TypeMismatch { .. }) => applier
.with_node::<SubcomposeLayoutNode, _>(node_id, |node| {
let needs_pointer_pass = node.needs_pointer_pass();
if needs_pointer_pass {
node.clear_needs_pointer_pass();
}
needs_pointer_pass
}),
Err(err) => Err(err),
}
}
DispatchInvalidationKind::Focus => {
match applier.with_node::<LayoutNode, _>(node_id, |node| {
let needs_focus_sync = node.needs_focus_sync();
if needs_focus_sync {
node.clear_needs_focus_sync();
}
needs_focus_sync
}) {
Ok(cleared) => Ok(cleared),
Err(NodeError::TypeMismatch { .. }) => applier
.with_node::<SubcomposeLayoutNode, _>(node_id, |node| {
let needs_focus_sync = node.needs_focus_sync();
if needs_focus_sync {
node.clear_needs_focus_sync();
}
needs_focus_sync
}),
Err(err) => Err(err),
}
}
}
}
pub(crate) fn build_draw_refresh_scope(
applier: &mut MemoryApplier,
dirty_nodes: &HashSet<NodeId>,
) -> HashSet<NodeId> {
let mut refresh_scope = HashSet::with_capacity(dirty_nodes.len());
for &dirty_node in dirty_nodes {
let mut current = Some(dirty_node);
while let Some(node_id) = current {
if !refresh_scope.insert(node_id) {
break;
}
current = applier.get_mut(node_id).ok().and_then(|node| node.parent());
}
}
refresh_scope
}
fn collect_retained_redraw_nodes(
applier: &mut MemoryApplier,
node_id: NodeId,
dirty_nodes: &mut Vec<NodeId>,
) {
let children = match applier.get_mut(node_id) {
Ok(node) => node.children(),
Err(_) => return,
};
let redraw = match applier.with_node::<LayoutNode, _>(node_id, |node| {
let needs_redraw = node.needs_redraw();
if needs_redraw {
node.clear_needs_redraw();
}
needs_redraw
}) {
Ok(needs_redraw) => needs_redraw,
Err(NodeError::TypeMismatch { .. }) => applier
.with_node::<SubcomposeLayoutNode, _>(node_id, |node| {
let needs_redraw = node.needs_redraw();
if needs_redraw {
node.clear_needs_redraw();
}
needs_redraw
})
.unwrap_or(false),
Err(_) => false,
};
if redraw {
dirty_nodes.push(node_id);
}
for child in children {
collect_retained_redraw_nodes(applier, child, dirty_nodes);
}
}
fn refresh_layout_box_data(
applier: &mut MemoryApplier,
layout: &mut cranpose_ui::layout::LayoutBox,
refresh_scope: &HashSet<NodeId>,
dirty_nodes: &HashSet<NodeId>,
) {
if !refresh_scope.contains(&layout.node_id) {
return;
}
if dirty_nodes.contains(&layout.node_id) {
if let Ok((modifier, resolved_modifiers, slices)) =
applier.with_node::<LayoutNode, _>(layout.node_id, |node| {
node.clear_needs_redraw();
(
node.modifier.clone(),
node.resolved_modifiers(),
node.modifier_slices_snapshot(),
)
})
{
layout.node_data.modifier = modifier;
layout.node_data.resolved_modifiers = resolved_modifiers;
layout.node_data.modifier_slices = slices;
} else if let Ok((modifier, resolved_modifiers)) = applier
.with_node::<SubcomposeLayoutNode, _>(layout.node_id, |node| {
node.clear_needs_redraw();
(node.modifier(), node.resolved_modifiers())
})
{
layout.node_data.modifier = modifier.clone();
layout.node_data.resolved_modifiers = resolved_modifiers;
layout.node_data.modifier_slices =
std::rc::Rc::new(cranpose_ui::collect_slices_from_modifier(&modifier));
}
}
for child in &mut layout.children {
refresh_layout_box_data(applier, child, refresh_scope, dirty_nodes);
}
}