Coalesce resize layout diagnostics

core/src/ui/render_state.rs

@@ -1,5 +1,5 @@
 #[cfg(feature = "layout-diagnostics")]
-use crate::layout_diagnostics::{self as diag, Counter, TimerKind};
+use crate::layout_diagnostics::{self as diag, Counter, ReuseOutcome, TimerKind};
 use crate::{
     ActiveData, Axis, DrawLayers, IdLike, MaskIdx, MoveIdx, Moves, OnResize, Painter, PixelRegion,
     Size, StrongWidget, UiRegion, UiRsc, WidgetId, Widgets,
@@ -37,8 +37,11 @@ impl UiRenderState {
     }
 
     pub fn resize(&mut self, size: impl Into<Vec2>) {
-        self.output_size = size.into();
-        self.resized = true;
+        let size = size.into();
+        if size != self.output_size {
+            self.output_size = size;
+            self.resized = true;
+        }
     }
 
     pub fn output_size(&self) -> Vec2 {
@@ -77,11 +80,17 @@ impl UiRenderState {
             {
                 #[cfg(feature = "layout-diagnostics")]
                 let _marking = diag::timer(TimerKind::ResizeMarking);
-                for (&id, active) in &self.active {
-                    if active.reads_output {
-                        #[cfg(feature = "layout-diagnostics")]
-                        diag::bump(Counter::ResizeDependents);
-                        rsc.widgets_mut().needs_redraw.insert(id);
+                let dependents: Vec<_> = self
+                    .active
+                    .iter()
+                    .filter_map(|(&id, active)| active.reads_output.then_some(id))
+                    .collect();
+                for id in dependents {
+                    #[cfg(feature = "layout-diagnostics")]
+                    diag::bump(Counter::ResizeDependents);
+                    rsc.widgets_mut().needs_redraw.insert(id);
+                    if let Some(top) = self.mark_readers(id, rsc) {
+                        rsc.widgets_mut().needs_redraw.insert(top);
                     }
                 }
             }
@@ -127,7 +136,10 @@ impl UiRenderState {
         rsc: &mut dyn UiRsc,
     ) -> Size {
         #[cfg(feature = "layout-diagnostics")]
-        diag::bump(Counter::DrawRequests);
+        {
+            diag::bump(Counter::DrawRequests);
+            diag::draw_request(id, parent, region, self.px_of(parent_move, region), slotted);
+        }
         let mut old_children = old_children.unwrap_or_default();
         if self.active.contains_key(&id) {
             if let Some(size) = self.try_reuse(id, region, parent_move, rsc) {
@@ -175,6 +187,8 @@ impl UiRenderState {
         let mut widget = painter.rsc.widgets().get_dyn_dynamic(id);
         let size = widget.draw(&mut painter);
         drop(widget);
+        #[cfg(feature = "layout-diagnostics")]
+        diag::size_reported(id, size);
 
         let Painter {
             state: _,
@@ -271,7 +285,10 @@ impl UiRenderState {
         diag::bump(Counter::ReuseAttempts);
         if rsc.widgets().needs_redraw.contains(&id) {
             #[cfg(feature = "layout-diagnostics")]
-            diag::bump(Counter::ReuseDirty);
+            {
+                diag::bump(Counter::ReuseDirty);
+                diag::reuse(id, ReuseOutcome::Dirty);
+            }
             return None;
         }
         let active = self.active.get(&id)?;
@@ -279,7 +296,10 @@ impl UiRenderState {
         // longer sits in, and its slot names the wrong parent.
         if active.parent_move != parent_move {
             #[cfg(feature = "layout-diagnostics")]
-            diag::bump(Counter::ReuseWrongParent);
+            {
+                diag::bump(Counter::ReuseWrongParent);
+                diag::reuse(id, ReuseOutcome::WrongParent);
+            }
             return None;
         }
         let (size, old_region, slot, old_px) =
@@ -294,7 +314,10 @@ impl UiRenderState {
         }
         if !changed.iter().any(|&c| c) && old_region == region {
             #[cfg(feature = "layout-diagnostics")]
-            diag::bump(Counter::ReuseExact);
+            {
+                diag::bump(Counter::ReuseExact);
+                diag::reuse(id, ReuseOutcome::Exact);
+            }
             return Some(size);
         }
         // Only a placed widget can be given a different box without drawing
@@ -302,7 +325,10 @@ impl UiRenderState {
         // entry says where all of it went.
         if slot == parent_move {
             #[cfg(feature = "layout-diagnostics")]
-            diag::bump(Counter::ReuseUnslotted);
+            {
+                diag::bump(Counter::ReuseUnslotted);
+                diag::reuse(id, ReuseOutcome::Unslotted);
+            }
             return None;
         }
         if changed.iter().any(|&c| c) {
@@ -316,12 +342,18 @@ impl UiRenderState {
             // and has to lay out around what it comes to.
             if redraws {
                 #[cfg(feature = "layout-diagnostics")]
-                diag::bump(Counter::ReuseOwnResize);
+                {
+                    diag::bump(Counter::ReuseOwnResize);
+                    diag::reuse(id, ReuseOutcome::OwnResize);
+                }
                 return None;
             }
             if self.redraws_under(id, changed, rsc) {
                 #[cfg(feature = "layout-diagnostics")]
-                diag::bump(Counter::ReuseDescendantResize);
+                {
+                    diag::bump(Counter::ReuseDescendantResize);
+                    diag::reuse(id, ReuseOutcome::DescendantResize);
+                }
                 return None;
             }
         }
@@ -330,7 +362,10 @@ impl UiRenderState {
         active.region = region;
         active.px = px;
         #[cfg(feature = "layout-diagnostics")]
-        diag::bump(Counter::ReuseMoved);
+        {
+            diag::bump(Counter::ReuseMoved);
+            diag::reuse(id, ReuseOutcome::Moved);
+        }
         Some(size)
     }
 
@@ -446,14 +481,16 @@ impl UiRenderState {
         let _layout = diag::timer(TimerKind::IncrementalLayout);
         // A reader's answer is only valid after every dirty size it reads has
         // settled. Equal-depth widgets are independent, so their order does
-        // not matter.
-        while let Some(id) = rsc
-            .widgets()
-            .needs_redraw
-            .iter()
-            .copied()
-            .max_by_key(|&id| self.depth(id))
-        {
+        // not matter. Resize dirtiness already marks whole reader chains, so
+        // choosing their shallowest roots coalesces descendants that share a
+        // reader and gives each changing box its final constraints first.
+        while let Some(id) = {
+            let dirty = rsc.widgets().needs_redraw.iter().copied();
+            match self.resized {
+                true => dirty.min_by_key(|&id| self.depth(id)),
+                false => dirty.max_by_key(|&id| self.depth(id)),
+            }
+        } {
             #[cfg(feature = "layout-diagnostics")]
             diag::bump(Counter::QueuePops);
             self.redraw(id, rsc);