separate saveLayer events into record and execute variants and trace more of the execution calls (#29598)

Author: flar

flow/display_list_canvas.cc

@@ -19,6 +19,7 @@ void DisplayListCanvasDispatcher::restore() {
 }
 void DisplayListCanvasDispatcher::saveLayer(const SkRect* bounds,
                                             bool restore_with_paint) {
+  TRACE_EVENT0("flutter", "Canvas::saveLayer");
   canvas_->saveLayer(bounds, restore_with_paint ? &paint() : nullptr);
 }
 
@@ -76,7 +77,14 @@ void DisplayListCanvasDispatcher::clipPath(const SkPath& path,
 }
 
 void DisplayListCanvasDispatcher::drawPaint() {
-  canvas_->drawPaint(paint());
+  const SkPaint& sk_paint = paint();
+  SkImageFilter* filter = sk_paint.getImageFilter();
+  if (filter && !filter->asColorFilter(nullptr)) {
+    // drawPaint does an implicit saveLayer if an SkImageFilter is
+    // present that cannot be replaced by an SkColorFilter.
+    TRACE_EVENT0("flutter", "Canvas::saveLayer");
+  }
+  canvas_->drawPaint(sk_paint);
 }
 void DisplayListCanvasDispatcher::drawColor(SkColor color, SkBlendMode mode) {
   canvas_->drawColor(color, mode);
@@ -170,8 +178,13 @@ void DisplayListCanvasDispatcher::drawAtlas(const sk_sp<SkImage> atlas,
 void DisplayListCanvasDispatcher::drawPicture(const sk_sp<SkPicture> picture,
                                               const SkMatrix* matrix,
                                               bool render_with_attributes) {
-  canvas_->drawPicture(picture, matrix,
-                       render_with_attributes ? &paint() : nullptr);
+  if (render_with_attributes) {
+    // drawPicture does an implicit saveLayer if an SkPaint is supplied.
+    TRACE_EVENT0("flutter", "Canvas::saveLayer");
+    canvas_->drawPicture(picture, matrix, &paint());
+  } else {
+    canvas_->drawPicture(picture, matrix, nullptr);
+  }
 }
 void DisplayListCanvasDispatcher::drawDisplayList(
     const sk_sp<DisplayList> display_list) {

flow/layers/layer.cc

@@ -65,6 +65,7 @@ Layer::AutoSaveLayer::AutoSaveLayer(const PaintContext& paint_context,
       canvas_(save_mode == SaveMode::kInternalNodesCanvas
                   ? *(paint_context.internal_nodes_canvas)
                   : *(paint_context.leaf_nodes_canvas)) {
+  TRACE_EVENT0("flutter", "Canvas::saveLayer");
   canvas_.saveLayer(bounds_, paint);
 }
 
@@ -76,6 +77,7 @@ Layer::AutoSaveLayer::AutoSaveLayer(const PaintContext& paint_context,
       canvas_(save_mode == SaveMode::kInternalNodesCanvas
                   ? *(paint_context.internal_nodes_canvas)
                   : *(paint_context.leaf_nodes_canvas)) {
+  TRACE_EVENT0("flutter", "Canvas::saveLayer");
   canvas_.saveLayer(layer_rec);
 }
 

lib/ui/painting/canvas.cc

@@ -105,7 +105,7 @@ void Canvas::saveLayerWithoutBounds(const Paint& paint,
   if (!canvas_) {
     return;
   }
-  TRACE_EVENT0("flutter", "Canvas::saveLayer");
+  TRACE_EVENT0("flutter", "ui.Canvas::saveLayer (Recorded)");
   canvas_->saveLayer(nullptr, paint.paint());
 }
 
@@ -118,7 +118,7 @@ void Canvas::saveLayer(double left,
   if (!canvas_) {
     return;
   }
-  TRACE_EVENT0("flutter", "Canvas::saveLayer");
+  TRACE_EVENT0("flutter", "ui.Canvas::saveLayer (Recorded)");
   SkRect bounds = SkRect::MakeLTRB(left, top, right, bottom);
   canvas_->saveLayer(&bounds, paint.paint());
 }
@@ -230,6 +230,13 @@ void Canvas::drawPaint(const Paint& paint, const PaintData& paint_data) {
   if (!canvas_) {
     return;
   }
+  const SkPaint* sk_paint = paint.paint();
+  SkImageFilter* filter = sk_paint->getImageFilter();
+  if (filter && !filter->asColorFilter(nullptr)) {
+    // drawPaint does an implicit saveLayer if an SkImageFilter is
+    // present that cannot be replaced by an SkColorFilter.
+    TRACE_EVENT0("flutter", "ui.Canvas::saveLayer (Recorded)");
+  }
   canvas_->drawPaint(*paint.paint());
 }
 

testing/dart/observatory/tracing_test.dart

@@ -23,9 +23,11 @@ void main() {
     );
 
     final Completer<void> completer = Completer<void>();
-    window.onBeginFrame = (Duration timeStamp) {
+    window.onBeginFrame = (Duration timeStamp) async {
       final PictureRecorder recorder = PictureRecorder();
       final Canvas canvas = Canvas(recorder);
+      canvas.drawColor(const Color(0xff0000ff), BlendMode.srcOut);
+      canvas.drawPaint(Paint()..imageFilter = ImageFilter.blur(sigmaX: 2, sigmaY: 3));
       canvas.saveLayer(null, Paint());
       canvas.saveLayer(const Rect.fromLTWH(0, 0, 100, 100), Paint());
       canvas.drawRect(const Rect.fromLTRB(10, 10, 20, 20), Paint());
@@ -37,7 +39,7 @@ void main() {
       builder.addPicture(Offset.zero, picture);
       final Scene scene = builder.build();
 
-      window.render(scene);
+      await scene.toImage(100, 100);
       scene.dispose();
       completer.complete();
     };
@@ -47,13 +49,20 @@ void main() {
     final vms.Timeline timeline = await vmService.getVMTimeline();
     await vmService.dispose();
 
+    int saveLayerRecordCount = 0;
     int saveLayerCount = 0;
     for (final vms.TimelineEvent event in timeline.traceEvents!) {
       final Map<String, dynamic> json = event.json!;
-      if (json['name'] == 'Canvas::saveLayer' && json['ph'] == 'B') {
-        saveLayerCount += 1;
+      if (json['ph'] == 'B') {
+        if (json['name'] == 'ui.Canvas::saveLayer (Recorded)') {
+          saveLayerRecordCount += 1;
+        }
+        if (json['name'] == 'Canvas::saveLayer') {
+          saveLayerCount += 1;
+        }
       }
     }
-    expect(saveLayerCount, 2);
+    expect(saveLayerRecordCount, 3);
+    expect(saveLayerCount, 3);
   });
 }