CanvasKit: memory management for image and shader classes (flutter#20349

)

* memory-manage images and shaders

ci/licenses_golden/licenses_flutter

@@ -451,6 +451,7 @@ FILE: ../../../flutter/lib/web_ui/lib/src/engine/compositor/picture_recorder.dar
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/compositor/platform_message.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/compositor/raster_cache.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/compositor/rasterizer.dart
+FILE: ../../../flutter/lib/web_ui/lib/src/engine/compositor/shader.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/compositor/skia_object_cache.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/compositor/surface.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/compositor/text.dart
@@ -489,7 +490,6 @@ FILE: ../../../flutter/lib/web_ui/lib/src/engine/services/buffers.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/services/message_codec.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/services/message_codecs.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/services/serialization.dart
-FILE: ../../../flutter/lib/web_ui/lib/src/engine/shader.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/shadow.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/surface/backdrop_filter.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/surface/canvas.dart
@@ -514,6 +514,7 @@ FILE: ../../../flutter/lib/web_ui/lib/src/engine/surface/recording_canvas.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/surface/render_vertices.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/surface/scene.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/surface/scene_builder.dart
+FILE: ../../../flutter/lib/web_ui/lib/src/engine/surface/shader.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/surface/surface.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/surface/surface_stats.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/surface/transform.dart

lib/web_ui/lib/src/engine.dart

@@ -52,6 +52,7 @@ part 'engine/compositor/picture_recorder.dart';
 part 'engine/compositor/platform_message.dart';
 part 'engine/compositor/raster_cache.dart';
 part 'engine/compositor/rasterizer.dart';
+part 'engine/compositor/shader.dart';
 part 'engine/compositor/skia_object_cache.dart';
 part 'engine/compositor/surface.dart';
 part 'engine/compositor/text.dart';
@@ -90,7 +91,6 @@ part 'engine/services/buffers.dart';
 part 'engine/services/message_codec.dart';
 part 'engine/services/message_codecs.dart';
 part 'engine/services/serialization.dart';
-part 'engine/shader.dart';
 part 'engine/shadow.dart';
 part 'engine/surface/backdrop_filter.dart';
 part 'engine/surface/canvas.dart';
@@ -115,6 +115,7 @@ part 'engine/surface/recording_canvas.dart';
 part 'engine/surface/render_vertices.dart';
 part 'engine/surface/scene.dart';
 part 'engine/surface/scene_builder.dart';
+part 'engine/surface/shader.dart';
 part 'engine/surface/surface.dart';
 part 'engine/surface/surface_stats.dart';
 part 'engine/surface/transform.dart';

lib/web_ui/lib/src/engine/compositor/canvaskit_api.dart

@@ -643,7 +643,11 @@ class SkImage {
   external void delete();
   external int width();
   external int height();
-  external SkShader makeShader(SkTileMode tileModeX, SkTileMode tileModeY);
+  external SkShader makeShader(
+    SkTileMode tileModeX,
+    SkTileMode tileModeY,
+    Float32List? matrix, // 3x3 matrix
+  );
 }
 
 @JS()
@@ -677,10 +681,24 @@ class SkShaderNamespace {
     Float32List? matrix, // 3x3 matrix
     int flags,
   );
+
+  external SkShader MakeSweepGradient(
+    double cx,
+    double cy,
+    List<Float32List> colors,
+    Float32List colorStops,
+    SkTileMode tileMode,
+    Float32List? matrix, // 3x3 matrix
+    int flags,
+    double startAngle,
+    double endAngle,
+  );
 }
 
 @JS()
-class SkShader {}
+class SkShader {
+  external void delete();
+}
 
 // This needs to be bound to top-level because SkPaint is initialized
 // with `new`. Also in Dart you can't write this:
@@ -1556,7 +1574,7 @@ class TypefaceFontProviderNamespace {
 Timer? _skObjectCollector;
 List<SkDeletable> _skObjectDeleteQueue = <SkDeletable>[];
 
-final SkObjectFinalizationRegistry skObjectFinalizationRegistry = SkObjectFinalizationRegistry(js.allowInterop((SkDeletable deletable) {
+final SkObjectFinalizationRegistry<SkDeletable> skObjectFinalizationRegistry = SkObjectFinalizationRegistry<SkDeletable>(js.allowInterop((SkDeletable deletable) {
   _skObjectDeleteQueue.add(deletable);
   _skObjectCollector ??= _scheduleSkObjectCollection();
 }));
@@ -1589,7 +1607,7 @@ Timer _scheduleSkObjectCollection() => Timer(Duration.zero, () {
   html.window.performance.measure('SkObject collection', 'SkObject collection-start', 'SkObject collection-end');
 });
 
-typedef SkObjectFinalizer = void Function(SkDeletable deletable);
+typedef SkObjectFinalizer<T> = void Function(T key);
 
 /// Any Skia object that has a `delete` method.
 @JS()
@@ -1613,8 +1631,8 @@ class SkDeletable {
 /// 5. The finalizer function is called with the SkPaint as the sole argument.
 /// 6. We call `delete` on SkPaint.
 @JS('window.FinalizationRegistry')
-class SkObjectFinalizationRegistry {
-  external SkObjectFinalizationRegistry(SkObjectFinalizer finalizer);
+class SkObjectFinalizationRegistry<T> {
+  external SkObjectFinalizationRegistry(SkObjectFinalizer<T> finalizer);
   external void register(Object ckObject, Object skObject);
 }
 

lib/web_ui/lib/src/engine/compositor/image.dart

@@ -39,11 +39,17 @@ void skiaInstantiateWebImageCodec(String src, Callback<ui.Codec> callback,
 class CkAnimatedImage implements ui.Image {
   final SkAnimatedImage _skAnimatedImage;
 
-  CkAnimatedImage(this._skAnimatedImage);
+  // Use a box because `SkImage` may be deleted either due to this object
+  // being garbage-collected, or by an explicit call to [delete].
+  late final SkiaObjectBox box;
+
+  CkAnimatedImage(this._skAnimatedImage) {
+    box = SkiaObjectBox(this, _skAnimatedImage as SkDeletable);
+  }
 
   @override
   void dispose() {
-    _skAnimatedImage.delete();
+    box.delete();
   }
 
   int get frameCount => _skAnimatedImage.getFrameCount();
@@ -77,11 +83,17 @@ class CkAnimatedImage implements ui.Image {
 class CkImage implements ui.Image {
   final SkImage skImage;
 
-  CkImage(this.skImage);
+  // Use a box because `SkImage` may be deleted either due to this object
+  // being garbage-collected, or by an explicit call to [delete].
+  late final SkiaObjectBox box;
+
+  CkImage(this.skImage) {
+    box = SkiaObjectBox(this, skImage as SkDeletable);
+  }
 
   @override
   void dispose() {
-    skImage.delete();
+    box.delete();
   }
 
   @override
@@ -99,26 +111,25 @@ class CkImage implements ui.Image {
 
 /// A [Codec] that wraps an `SkAnimatedImage`.
 class CkAnimatedImageCodec implements ui.Codec {
-  CkAnimatedImage? animatedImage;
+  CkAnimatedImage animatedImage;
 
   CkAnimatedImageCodec(this.animatedImage);
 
   @override
   void dispose() {
-    animatedImage!.dispose();
-    animatedImage = null;
+    animatedImage.dispose();
   }
 
   @override
-  int get frameCount => animatedImage!.frameCount;
+  int get frameCount => animatedImage.frameCount;
 
   @override
-  int get repetitionCount => animatedImage!.repetitionCount;
+  int get repetitionCount => animatedImage.repetitionCount;
 
   @override
   Future<ui.FrameInfo> getNextFrame() {
-    final Duration duration = animatedImage!.decodeNextFrame();
-    final CkImage image = animatedImage!.currentFrameAsImage;
+    final Duration duration = animatedImage.decodeNextFrame();
+    final CkImage image = animatedImage.currentFrameAsImage;
     return Future<ui.FrameInfo>.value(AnimatedImageFrameInfo(duration, image));
   }
 }

lib/web_ui/lib/src/engine/compositor/painting.dart

@@ -117,17 +117,17 @@ class CkPaint extends ManagedSkiaObject<SkPaint> implements ui.Paint {
   bool _invertColors = false;
 
   @override
-  ui.Shader? get shader => _shader as ui.Shader?;
+  ui.Shader? get shader => _shader;
   @override
   set shader(ui.Shader? value) {
     if (_shader == value) {
       return;
     }
-    _shader = value as EngineShader?;
-    skiaObject.setShader(_shader?.createSkiaShader());
+    _shader = value as CkShader?;
+    skiaObject.setShader(_shader?.skiaObject);
   }
 
-  EngineShader? _shader;
+  CkShader? _shader;
 
   @override
   ui.MaskFilter? get maskFilter => _maskFilter;
@@ -222,7 +222,7 @@ class CkPaint extends ManagedSkiaObject<SkPaint> implements ui.Paint {
     paint.setStrokeWidth(_strokeWidth);
     paint.setAntiAlias(_isAntiAlias);
     paint.setColorInt(_color.value);
-    paint.setShader(_shader?.createSkiaShader());
+    paint.setShader(_shader?.skiaObject);
     paint.setMaskFilter(_ckMaskFilter?.skiaObject);
     paint.setColorFilter(_ckColorFilter?.skiaObject);
     paint.setImageFilter(_imageFilter?.skiaObject);