Web ImageFilter.matrix support

lib/web_ui/lib/src/engine/canvaskit/image_filter.dart

@@ -2,11 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:typed_data';
+
 import 'package:ui/ui.dart' as ui;
 
 import 'canvaskit_api.dart';
 import 'color_filter.dart';
 import 'skia_object_cache.dart';
+import '../util.dart';
 
 /// An [ImageFilter] that can create a managed skia [SkImageFilter] object.
 ///
@@ -22,7 +25,7 @@ abstract class CkManagedSkImageFilterConvertible<T extends Object>
 
 /// The CanvasKit implementation of [ui.ImageFilter].
 ///
-/// Currently only supports `blur`.
+/// Currently only supports `blur`, `matrix`, and ColorFilters.
 abstract class CkImageFilter extends ManagedSkiaObject<SkImageFilter>
     implements CkManagedSkImageFilterConvertible<SkImageFilter> {
   factory CkImageFilter.blur(
@@ -31,6 +34,9 @@ abstract class CkImageFilter extends ManagedSkiaObject<SkImageFilter>
       required ui.TileMode tileMode}) = _CkBlurImageFilter;
   factory CkImageFilter.color({required CkColorFilter colorFilter}) =
       CkColorFilterImageFilter;
+  factory CkImageFilter.matrix(
+      {required Float64List matrix,
+      required ui.FilterQuality filterQuality}) = _CkMatrixImageFilter;
 
   CkImageFilter._();
 
@@ -126,3 +132,35 @@ class _CkBlurImageFilter extends CkImageFilter {
     return 'ImageFilter.blur($sigmaX, $sigmaY, $_modeString)';
   }
 }
+
+class _CkMatrixImageFilter extends CkImageFilter {
+  _CkMatrixImageFilter({ required Float64List matrix, required this.filterQuality })
+      : this.matrix = Float64List.fromList(matrix),
+        super._();
+
+  final Float64List matrix;
+  final ui.FilterQuality filterQuality;
+
+  SkImageFilter _initSkiaObject() {
+    return canvasKit.ImageFilter.MakeMatrixTransform(
+      toSkMatrixFromFloat64(matrix),
+      toSkFilterQuality(filterQuality),
+      null,
+    );
+  }
+
+  @override
+  bool operator ==(Object other) {
+    if (other.runtimeType != runtimeType)
+      return false;
+    return other is _CkMatrixImageFilter
+        && other.filterQuality == filterQuality
+        && listEquals<double>(other.matrix, matrix);
+  }
+
+  @override
+  int get hashCode => ui.hashValues(filterQuality, ui.hashList(matrix));
+
+  @override
+  String toString() => 'ImageFilter.matrix($matrix, $filterQuality)';
+}

lib/web_ui/lib/src/engine/html/backdrop_filter.dart

@@ -113,9 +113,9 @@ class PersistedBackdropFilter extends PersistedContainerSurface
       // the blur will fall within 2 * sigma pixels.
       if (browserEngine == BrowserEngine.webkit) {
         DomRenderer.setElementStyle(_filterElement!, '-webkit-backdrop-filter',
-            _imageFilterToCss(filter));
+            filter.filterAttribute);
       }
-      DomRenderer.setElementStyle(_filterElement!, 'backdrop-filter', _imageFilterToCss(filter));
+      DomRenderer.setElementStyle(_filterElement!, 'backdrop-filter', filter.filterAttribute);
     }
   }
 

lib/web_ui/lib/src/engine/html/image_filter.dart

@@ -18,7 +18,8 @@ class PersistedImageFilter extends PersistedContainerSurface
 
   @override
   void apply() {
-    rootElement!.style.filter = _imageFilterToCss(filter as EngineImageFilter);
+    rootElement!.style.filter = (filter as EngineImageFilter).filterAttribute;
+    rootElement!.style.transform = (filter as EngineImageFilter).transformAttribute;
   }
 
   @override

lib/web_ui/lib/src/engine/html/scene_builder.dart

@@ -582,10 +582,3 @@ class SurfaceSceneBuilder implements ui.SceneBuilder {
     throw UnimplementedError();
   }
 }
-
-// HTML only supports a single radius, but Flutter ImageFilter supports separate
-// horizontal and vertical radii. The best approximation we can provide is to
-// average the two radii together for a single compromise value.
-String _imageFilterToCss(EngineImageFilter filter) {
-  return 'blur(${(filter.sigmaX + filter.sigmaY) / 2}px)';
-}

lib/web_ui/lib/src/engine/html/shaders/shader.dart

@@ -660,25 +660,79 @@ class GradientConical extends GradientRadial {
 
 /// Backend implementation of [ui.ImageFilter].
 ///
-/// Currently only `blur` is supported.
-class EngineImageFilter implements ui.ImageFilter {
-  EngineImageFilter.blur({this.sigmaX = 0.0, this.sigmaY = 0.0});
+/// Currently only `blur` and `matrix` are supported.
+abstract class EngineImageFilter implements ui.ImageFilter {
+  factory EngineImageFilter.blur({
+    required double sigmaX,
+    required double sigmaY,
+    required ui.TileMode tileMode,
+  }) = _BlurEngineImageFilter;
+
+  factory EngineImageFilter.matrix({
+    required Float64List matrix,
+    required ui.FilterQuality filterQuality,
+  }) = _MatrixEngineImageFilter;
+
+  EngineImageFilter._();
+
+  String get filterAttribute => '';
+  String get transformAttribute => '';
+}
+
+class _BlurEngineImageFilter extends EngineImageFilter {
+  _BlurEngineImageFilter({ this.sigmaX = 0.0, this.sigmaY = 0.0, this.tileMode = ui.TileMode.clamp }) : super._();
 
   final double sigmaX;
   final double sigmaY;
+  final ui.TileMode tileMode;
+
+  // TODO(flutter_web): implement TileMode.
+  String get filterAttribute => blurSigmasToCssString(sigmaX, sigmaY);
 
   @override
   bool operator ==(Object other) {
-    return other is EngineImageFilter &&
+    if (other.runtimeType != runtimeType)
+      return false;
+    return other is _BlurEngineImageFilter &&
+        other.tileMode == tileMode &&
         other.sigmaX == sigmaX &&
         other.sigmaY == sigmaY;
   }
 
   @override
-  int get hashCode => ui.hashValues(sigmaX, sigmaY);
+  int get hashCode => ui.hashValues(sigmaX, sigmaY, tileMode);
+
+  @override
+  String toString() {
+    return 'ImageFilter.blur($sigmaX, $sigmaY, $tileMode)';
+  }
+}
+
+class _MatrixEngineImageFilter extends EngineImageFilter {
+  _MatrixEngineImageFilter({ required Float64List matrix, required this.filterQuality })
+      : webMatrix = Float64List.fromList(matrix),
+        super._();
+
+  final Float64List webMatrix;
+  final ui.FilterQuality filterQuality;
+
+  // TODO(flutter_web): implement FilterQuality.
+  String get transformAttribute => float64ListToCssTransform(webMatrix);
+
+  @override
+  bool operator ==(Object other) {
+    if (other.runtimeType != runtimeType)
+      return false;
+    return other is _MatrixEngineImageFilter
+        && other.filterQuality == filterQuality
+        && listEquals<double>(other.webMatrix, webMatrix);
+  }
+
+  @override
+  int get hashCode => ui.hashValues(ui.hashList(webMatrix), filterQuality);
 
   @override
   String toString() {
-    return 'ImageFilter.blur($sigmaX, $sigmaY)';
+    return 'ImageFilter.matrix($webMatrix, $filterQuality)';
   }
 }

lib/web_ui/lib/src/engine/util.dart

@@ -81,7 +81,7 @@ void setElementTransform(html.Element element, Float32List matrix4) {
 /// See also:
 ///  * https://github.com/flutter/flutter/issues/32274
 ///  * https://bugs.chromium.org/p/chromium/issues/detail?id=1040222
-String float64ListToCssTransform(Float32List matrix) {
+String float64ListToCssTransform(List<double> matrix) {
   assert(matrix.length == 16);
   final TransformKind transformKind = transformKindOf(matrix);
   if (transformKind == TransformKind.transform2d) {
@@ -113,9 +113,9 @@ enum TransformKind {
 }
 
 /// Detects the kind of transform the [matrix] performs.
-TransformKind transformKindOf(Float32List matrix) {
+TransformKind transformKindOf(List<double> matrix) {
   assert(matrix.length == 16);
-  final Float32List m = matrix;
+  final List<double> m = matrix;
 
   // If matrix contains scaling, rotation, z translation or
   // perspective transform, it is not considered simple.
@@ -171,15 +171,15 @@ bool isIdentityFloat32ListTransform(Float32List matrix) {
 /// permitted. However, it is inefficient to construct a matrix for an identity
 /// transform. Consider removing the CSS `transform` property from elements
 /// that apply identity transform.
-String float64ListToCssTransform2d(Float32List matrix) {
+String float64ListToCssTransform2d(List<double> matrix) {
   assert(transformKindOf(matrix) != TransformKind.complex);
   return 'matrix(${matrix[0]},${matrix[1]},${matrix[4]},${matrix[5]},${matrix[12]},${matrix[13]})';
 }
 
 /// Converts [matrix] to a 3D CSS transform value.
-String float64ListToCssTransform3d(Float32List matrix) {
+String float64ListToCssTransform3d(List<double> matrix) {
   assert(matrix.length == 16);
-  final Float32List m = matrix;
+  final List<double> m = matrix;
   if (m[0] == 1.0 &&
       m[1] == 0.0 &&
       m[2] == 0.0 &&
@@ -552,3 +552,10 @@ bool listEquals<T>(List<T>? a, List<T>? b) {
   }
   return true;
 }
+
+// HTML only supports a single radius, but Flutter ImageFilter supports separate
+// horizontal and vertical radii. The best approximation we can provide is to
+// average the two radii together for a single compromise value.
+String blurSigmasToCssString(double sigmaX, double sigmaY) {
+  return 'blur(${(sigmaX + sigmaY) * 0.5}px)';
+}

lib/web_ui/lib/src/ui/painting.dart

@@ -399,14 +399,18 @@ class ImageFilter {
     if (engine.useCanvasKit) {
       return engine.CkImageFilter.blur(sigmaX: sigmaX, sigmaY: sigmaY, tileMode: tileMode);
     }
-    return engine.EngineImageFilter.blur(sigmaX: sigmaX, sigmaY: sigmaY);
+    // TODO(flutter_web): implement TileMode.
+    return engine.EngineImageFilter.blur(sigmaX: sigmaX, sigmaY: sigmaY, tileMode: tileMode);
   }
 
-  ImageFilter.matrix(Float64List matrix4, {FilterQuality filterQuality = FilterQuality.low}) {
-    // TODO(flutter_web): add implementation.
-    throw UnimplementedError('ImageFilter.matrix not implemented for web platform.');
-    //    if (matrix4.length != 16)
-    //      throw ArgumentError('"matrix4" must have 16 entries.');
+  factory ImageFilter.matrix(Float64List matrix4, {FilterQuality filterQuality = FilterQuality.low}) {
+    if (matrix4.length != 16)
+      throw ArgumentError('"matrix4" must have 16 entries.');
+    if (engine.useCanvasKit) {
+      return engine.CkImageFilter.matrix(matrix: matrix4, filterQuality: filterQuality);
+    }
+    // TODO(flutter_web): implement FilterQuality.
+    return engine.EngineImageFilter.matrix(matrix: matrix4, filterQuality: filterQuality);
   }
 
   ImageFilter.compose({required ImageFilter outer, required ImageFilter inner}) {

lib/web_ui/test/engine/surface/filters/image_filter_test.dart

@@ -0,0 +1,79 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:typed_data';
+
+import 'package:test/bootstrap/browser.dart';
+import 'package:test/test.dart';
+import 'package:ui/src/engine.dart';
+import 'package:ui/ui.dart';
+
+void main() {
+  internalBootstrapBrowserTest(() => testMain);
+}
+
+void testMain() {
+  group('ImageFilter constructors', () {
+    test('matrix is copied', () {
+      Matrix4 matrix = Matrix4.identity();
+      Float64List storage = matrix.toFloat64();
+      ImageFilter filter1 = ImageFilter.matrix(storage);
+      storage[0] = 2.0;
+      ImageFilter filter2 = ImageFilter.matrix(storage);
+      expect(filter1, filter1);
+      expect(filter2, filter2);
+      expect(filter1, isNot(equals(filter2)));
+      expect(filter2, isNot(equals(filter1)));
+    });
+
+    test('matrix tests all values on ==', () {
+      Matrix4 matrix = Matrix4.identity();
+      Float64List storage = matrix.toFloat64();
+      ImageFilter filter1a = ImageFilter.matrix(storage, filterQuality: FilterQuality.none);
+      ImageFilter filter1b = ImageFilter.matrix(storage, filterQuality: FilterQuality.high);
+
+      storage[0] = 2.0;
+      ImageFilter filter2a = ImageFilter.matrix(storage, filterQuality: FilterQuality.none);
+      ImageFilter filter2b = ImageFilter.matrix(storage, filterQuality: FilterQuality.high);
+
+      expect(filter1a, filter1a);
+      expect(filter1a, isNot(equals(filter1b)));
+      expect(filter1a, isNot(equals(filter2a)));
+      expect(filter1a, isNot(equals(filter2b)));
+
+      expect(filter1b, isNot(equals(filter1a)));
+      expect(filter1b, filter1b);
+      expect(filter1b, isNot(equals(filter2a)));
+      expect(filter1b, isNot(equals(filter2b)));
+
+      expect(filter2a, isNot(equals(filter1a)));
+      expect(filter2a, isNot(equals(filter1b)));
+      expect(filter2a, filter2a);
+      expect(filter2a, isNot(equals(filter2b)));
+
+      expect(filter2b, isNot(equals(filter1a)));
+      expect(filter2b, isNot(equals(filter1b)));
+      expect(filter2b, isNot(equals(filter2a)));
+      expect(filter2b, filter2b);
+    });
+
+    test('blur tests all values on ==', () {
+      ImageFilter filter1 = ImageFilter.blur(sigmaX: 2.0, sigmaY: 2.0, tileMode: TileMode.decal);
+      ImageFilter filter2 = ImageFilter.blur(sigmaX: 2.0, sigmaY: 3.0, tileMode: TileMode.decal);
+      ImageFilter filter3 = ImageFilter.blur(sigmaX: 2.0, sigmaY: 2.0, tileMode: TileMode.mirror);
+
+      expect(filter1, filter1);
+      expect(filter1, isNot(equals(filter2)));
+      expect(filter1, isNot(equals(filter3)));
+
+      expect(filter2, isNot(equals(filter1)));
+      expect(filter2, filter2);
+      expect(filter2, isNot(equals(filter3)));
+
+      expect(filter3, isNot(equals(filter1)));
+      expect(filter3, isNot(equals(filter2)));
+      expect(filter3, filter3);
+    });
+  });
+}

lib/web_ui/test/golden_tests/engine/compositing_golden_test.dart

@@ -361,7 +361,7 @@ void testMain() async {
     viewElement6.remove();
   });
 
-  test('pushImageFilter', () async {
+  test('pushImageFilter blur', () async {
     final SurfaceSceneBuilder builder = SurfaceSceneBuilder();
     builder.pushImageFilter(
       ImageFilter.blur(sigmaX: 1, sigmaY: 3),
@@ -374,6 +374,25 @@ void testMain() async {
     await matchGoldenFile('compositing_image_filter.png', region: region);
   });
 
+  test('pushImageFilter matrix', () async {
+    final SurfaceSceneBuilder builder = SurfaceSceneBuilder();
+    builder.pushImageFilter(
+      ImageFilter.matrix(
+          (
+              Matrix4.identity()
+                ..translate(40, 10)
+                ..rotateZ(math.pi / 6)
+                ..scale(0.75, 0.75)
+          ).toFloat64()),
+    );
+    _drawTestPicture(builder);
+    builder.pop();
+
+    html.document.body.append(builder.build().webOnlyRootElement);
+
+    await matchGoldenFile('compositing_image_filter_matrix.png', region: region);
+  });
+
   group('Cull rect computation', () {
     _testCullRectComputation();
   });