test: canvas paint test.

Author: andycall

webf/lib/src/html/canvas/canvas.dart

@@ -25,18 +25,19 @@ class RenderCanvasPaint extends RenderCustomPaint {
   @override
   bool get isRepaintBoundary => true;
 
-  RenderCanvasPaint(
-      {required CustomPainter painter, required Size preferredSize})
+  @override
+  CanvasPainter? get painter => super.painter as CanvasPainter;
+
+  RenderCanvasPaint({required CustomPainter painter, required Size preferredSize})
       : super(
-          painter: painter,
-          foregroundPainter: null, // Ignore foreground painter
-          preferredSize: preferredSize,
-        );
+            painter: painter,
+            foregroundPainter: null, // Ignore foreground painter
+            preferredSize: preferredSize);
 
   @override
   void paint(PaintingContext context, Offset offset) {
-    context.pushClipRect(needsCompositing, offset,
-        Rect.fromLTWH(0, 0, preferredSize.width, preferredSize.height),
+    if (painter?.context == null) return;
+    context.pushClipRect(true, offset, Rect.fromLTWH(0, 0, preferredSize.width, preferredSize.height),
         (context, offset) {
       super.paint(context, offset);
     });
@@ -71,18 +72,15 @@ class CanvasElement extends Element {
   @override
   void initializeMethods(Map<String, BindingObjectMethod> methods) {
     super.initializeMethods(methods);
-    methods['getContext'] = BindingObjectMethodSync(
-        call: (args) => getContext(castToType<String>(args[0])));
+    methods['getContext'] = BindingObjectMethodSync(call: (args) => getContext(castToType<String>(args[0])));
   }
 
   @override
   void initializeProperties(Map<String, BindingObjectProperty> properties) {
     super.initializeProperties(properties);
-    properties['width'] = BindingObjectProperty(
-        getter: () => width, setter: (value) => width = castToType<int>(value));
-    properties['height'] = BindingObjectProperty(
-        getter: () => height,
-        setter: (value) => height = castToType<int>(value));
+    properties['width'] = BindingObjectProperty(getter: () => width, setter: (value) => width = castToType<int>(value));
+    properties['height'] =
+        BindingObjectProperty(getter: () => height, setter: (value) => height = castToType<int>(value));
   }
 
   @override
@@ -113,7 +111,8 @@ class CanvasElement extends Element {
           painter.dispose();
         }
 
-        context2d = CanvasRenderingContext2D(BindingContext(ownerView, ownerView.contextId, allocateNewBindingObject()), this);
+        context2d =
+            CanvasRenderingContext2D(BindingContext(ownerView, ownerView.contextId, allocateNewBindingObject()), this);
         painter.context = context2d;
 
         return context2d!;

webf/lib/src/html/canvas/canvas_context_2d.dart

@@ -382,7 +382,6 @@ class CanvasRenderingContext2D extends DynamicBindingObject {
   // HACK: We need record the current matrix state because flutter canvas not export resetTransform now.
   // https://github.com/flutter/engine/pull/25449
   Matrix4 _matrix = Matrix4.identity();
-  Matrix4 _lastMatrix = Matrix4.identity();
 
   int get actionCount => _actions.length;
 
@@ -408,10 +407,6 @@ class CanvasRenderingContext2D extends DynamicBindingObject {
 
   // Perform canvas drawing.
   List<CanvasAction> performActions(Canvas canvas, Size size) {
-    // HACK: Must sync transform first because each paint will saveLayer and restore that make the transform not effect
-    if (!_lastMatrix.isIdentity()) {
-      canvas.transform(_lastMatrix.storage);
-    }
     _pendingActions = _actions;
     _actions = [];
     for (int i = 0; i < _pendingActions.length; i++) {
@@ -422,9 +417,6 @@ class CanvasRenderingContext2D extends DynamicBindingObject {
 
   // Clear the saved pending actions.
   void clearActions(List<CanvasAction> actions) {
-    if (_lastMatrix != _matrix) {
-      _lastMatrix = _matrix.clone();
-    }
     actions.clear();
   }
 
@@ -1276,7 +1268,6 @@ class CanvasRenderingContext2D extends DynamicBindingObject {
     _actions = [];
     _states.clear();
     _matrix = Matrix4.identity();
-    _lastMatrix = Matrix4.identity();
     _textAlign = TextAlign.start;
     _textBaseline = CanvasTextBaseline.alphabetic;
     _direction = TextDirection.ltr;

webf/lib/src/html/canvas/canvas_painter.dart

@@ -14,7 +14,6 @@ class CanvasPainter extends CustomPainter {
 
   CanvasRenderingContext2D? context;
 
-  final Paint _saveLayerPaint = Paint();
   final Paint _snapshotPaint = Paint();
 
   // Cache the last paint image.
@@ -49,62 +48,23 @@ class CanvasPainter extends CustomPainter {
   }
 
   @override
-  void paint(Canvas canvas, Size size) async {
-    if (_hasSnapshot && !_shouldPainting) {
-      return canvas.drawImage(_snapshot!, Offset.zero, _snapshotPaint);
-    }
-
-    final PictureRecorder pictureRecorder = PictureRecorder();
-    final Canvas recordCanvas = Canvas(pictureRecorder);
-
+  void paint(Canvas canvas, Size size) {
     if (_scaleX != 1.0 || _scaleY != 1.0) {
-      recordCanvas.scale(_scaleX, _scaleY);
-    }
-
-    // This lets you create composite effects, for example making a group of drawing commands semi-transparent.
-    // Without using saveLayer, each part of the group would be painted individually,
-    // so where they overlap would be darker than where they do not. By using saveLayer to group them together,
-    // they can be drawn with an opaque color at first,
-    // and then the entire group can be made transparent using the saveLayer's paint.
-    recordCanvas.saveLayer(null, _saveLayerPaint);
-
-    // Paint last content
-    if (_hasSnapshot) {
-      recordCanvas.drawImage(_snapshot!, Offset.zero, _snapshotPaint);
-      _disposeSnapshot();
+      canvas.scale(_scaleX, _scaleY);
     }
 
     // Paint new actions
     List<CanvasAction>? actions;
     if (_shouldPainting) {
-      actions = context!.performActions(recordCanvas, size);
+      actions = context!.performActions(canvas, size);
     }
 
-    // Must pair each call to save()/saveLayer() with a later matching call to restore().
-    recordCanvas.restore();
-
-    // After calling this function, both the picture recorder
-    // and the canvas objects are invalid and cannot be used further.
-    final Picture picture = pictureRecorder.endRecording();
-    canvas.drawPicture(picture);
-
-    // Must flat picture to image, or raster will accept a growing command buffer.
-    await _createSnapshot(picture, size);
-
-    // Dispose the used picture.
-    picture.dispose();
     // Clear actions after snapshot was created, or next frame call may empty.
     if (actions != null) {
       context!.clearActions(actions);
     }
   }
 
-  Future<void> _createSnapshot(Picture picture, Size size) async {
-    _updatingSnapshot = true;
-    _snapshot = await picture.toImage(size.width.toInt(), size.height.toInt());
-    _updatingSnapshot = false;
-  }
-
   @override
   bool shouldRepaint(CanvasPainter oldDelegate) {
     if (_shouldRepaint) {