Convert MaskFilter to pure-Dart. (flutter#4534)

lib/ui/BUILD.gn

@@ -28,8 +28,6 @@ source_set("ui") {
     "painting/image_filter.h",
     "painting/image_shader.cc",
     "painting/image_shader.h",
-    "painting/mask_filter.cc",
-    "painting/mask_filter.h",
     "painting/matrix.cc",
     "painting/matrix.h",
     "painting/paint.cc",

lib/ui/dart_ui.cc

@@ -14,7 +14,6 @@
 #include "flutter/lib/ui/painting/image.h"
 #include "flutter/lib/ui/painting/image_filter.h"
 #include "flutter/lib/ui/painting/image_shader.h"
-#include "flutter/lib/ui/painting/mask_filter.h"
 #include "flutter/lib/ui/painting/path.h"
 #include "flutter/lib/ui/painting/picture.h"
 #include "flutter/lib/ui/painting/picture_recorder.h"
@@ -59,7 +58,6 @@ void DartUI::InitForGlobal() {
     FrameInfo::RegisterNatives(g_natives);
     ImageFilter::RegisterNatives(g_natives);
     ImageShader::RegisterNatives(g_natives);
-    MaskFilter::RegisterNatives(g_natives);
     Paragraph::RegisterNatives(g_natives);
     ParagraphBuilder::RegisterNatives(g_natives);
     Picture::RegisterNatives(g_natives);

lib/ui/painting.dart

@@ -562,6 +562,9 @@ class Paint {
   static const int _kColorFilterIndex = 9;
   static const int _kColorFilterColorIndex = 10;
   static const int _kColorFilterBlendModeIndex = 11;
+  static const int _kMaskFilterIndex = 12;
+  static const int _kMaskFilterBlurStyleIndex = 13;
+  static const int _kMaskFilterSigmaIndex = 14;
 
   static const int _kIsAntiAliasOffset = _kIsAntiAliasIndex << 2;
   static const int _kColorOffset = _kColorIndex << 2;
@@ -575,14 +578,16 @@ class Paint {
   static const int _kColorFilterOffset = _kColorFilterIndex << 2;
   static const int _kColorFilterColorOffset = _kColorFilterColorIndex << 2;
   static const int _kColorFilterBlendModeOffset = _kColorFilterBlendModeIndex << 2;
+  static const int _kMaskFilterOffset = _kMaskFilterIndex << 2;
+  static const int _kMaskFilterBlurStyleOffset = _kMaskFilterBlurStyleIndex << 2;
+  static const int _kMaskFilterSigmaOffset = _kMaskFilterSigmaIndex << 2;
   // If you add more fields, remember to update _kDataByteCount.
-  static const int _kDataByteCount = 48;
+  static const int _kDataByteCount = 75;
 
   // Binary format must match the deserialization code in paint.cc.
   List<dynamic> _objects;
-  static const int _kMaskFilterIndex = 0;
-  static const int _kShaderIndex = 1;
-  static const int _kObjectCount = 2;  // Must be one larger than the largest index
+  static const int _kShaderIndex = 0;
+  static const int _kObjectCount = 1; // Must be one larger than the largest index.
 
   /// Whether to apply anti-aliasing to lines and images drawn on the
   /// canvas.
@@ -735,13 +740,29 @@ class Paint {
   ///
   /// See [MaskFilter] for details.
   MaskFilter get maskFilter {
-    if (_objects == null)
-      return null;
-    return _objects[_kMaskFilterIndex];
+    switch (_data.getInt32(_kMaskFilterOffset, _kFakeHostEndian)) {
+      case MaskFilter._TypeNone:
+        return null;
+      case MaskFilter._TypeBlur:
+        return new MaskFilter.blur(
+          BlurStyle.values[_data.getInt32(_kMaskFilterBlurStyleOffset, _kFakeHostEndian)],
+          _data.getFloat32(_kMaskFilterSigmaOffset, _kFakeHostEndian),
+        );
+    }
+    return null;
   }
   set maskFilter(MaskFilter value) {
-    _objects ??= new List<dynamic>(_kObjectCount);
-    _objects[_kMaskFilterIndex] = value;
+    if (value == null) {
+      _data.setInt32(_kMaskFilterOffset, MaskFilter._TypeNone, _kFakeHostEndian);
+      _data.setInt32(_kMaskFilterBlurStyleOffset, 0, _kFakeHostEndian);
+      _data.setFloat32(_kMaskFilterSigmaOffset, 0.0, _kFakeHostEndian);
+    } else {
+      // For now we only support one kind of MaskFilter, so we don't need to
+      // check what the type is if it's not null.
+      _data.setInt32(_kMaskFilterOffset, MaskFilter._TypeBlur, _kFakeHostEndian);
+      _data.setInt32(_kMaskFilterBlurStyleOffset, value._style.index, _kFakeHostEndian);
+      _data.setFloat32(_kMaskFilterSigmaOffset, value._sigma, _kFakeHostEndian);
+    }
   }
 
   /// Controls the performance vs quality trade-off to use when applying
@@ -1291,7 +1312,7 @@ enum BlurStyle {
 /// color pixels.
 ///
 /// Instances of this class are used with [Paint.maskFilter] on [Paint] objects.
-class MaskFilter extends NativeFieldWrapperClass2 {
+class MaskFilter {
   /// Creates a mask filter that takes the shape being drawn and blurs it.
   ///
   /// This is commonly used to approximate shadows.
@@ -1304,11 +1325,40 @@ class MaskFilter extends NativeFieldWrapperClass2 {
   /// in pixels.
   ///
   /// A blur is an expensive operation and should therefore be used sparingly.
-  MaskFilter.blur(BlurStyle style, double sigma) {
-    assert(style != null);
-    _constructor(style.index, sigma);
+  ///
+  /// The arguments must not be null.
+  ///
+  /// See also:
+  ///
+  ///  * [Canvas.drawShadow], which is a more efficient way to draw shadows.
+  const MaskFilter.blur(
+    this._style,
+    this._sigma,
+  ) : assert(_style != null),
+      assert(_sigma != null);
+
+  final BlurStyle _style;
+  final double _sigma;
+
+  // The type of MaskFilter class to create for Skia.
+  // These constants must be kept in sync with MaskFilterType in paint.cc.
+  static const int _TypeNone = 0; // null
+  static const int _TypeBlur = 1; // SkBlurMaskFilter
+
+  @override
+  bool operator ==(dynamic other) {
+    if (other is! MaskFilter)
+      return false;
+    final MaskFilter typedOther = other;
+    return _style == typedOther._style &&
+           _sigma == typedOther._sigma;
   }
-  void _constructor(int style, double sigma) native "MaskFilter_constructor";
+
+  @override
+  int get hashCode => hashValues(_style, _sigma);
+
+  @override
+  String toString() => "MaskFilter.blur($_style, ${_sigma.toStringAsFixed(1)})";
 }
 
 /// A description of a color filter to apply when drawing a shape or compositing
@@ -2406,10 +2456,14 @@ class Canvas extends NativeFieldWrapperClass2 {
 
   /// Draws a shadow for a [Path] representing the given material elevation.
   ///
-  /// transparentOccluder should be true if the occluding object is not opaque.
+  /// The `transparentOccluder` argument should be true if the occluding object
+  /// is not opaque.
+  ///
+  /// The arguments must not be null.
   void drawShadow(Path path, Color color, double elevation, bool transparentOccluder) {
     assert(path != null); // path is checked on the engine side
     assert(color != null);
+    assert(transparentOccluder != null);
     _drawShadow(path, color.value, elevation, transparentOccluder);
   }
   void _drawShadow(Path path,

lib/ui/painting/paint.cc

@@ -4,19 +4,20 @@
 
 #include "flutter/lib/ui/painting/paint.h"
 
-#include "flutter/lib/ui/painting/mask_filter.h"
 #include "flutter/lib/ui/painting/shader.h"
 #include "lib/fxl/logging.h"
 #include "lib/tonic/typed_data/dart_byte_data.h"
 #include "third_party/skia/include/core/SkColorFilter.h"
 #include "third_party/skia/include/core/SkMaskFilter.h"
 #include "third_party/skia/include/core/SkShader.h"
 #include "third_party/skia/include/core/SkString.h"
+#include "third_party/skia/include/effects/SkBlurMaskFilter.h"
 
 using namespace blink;
 
 namespace tonic {
 
+// Indices for 32bit values.
 constexpr int kIsAntiAliasIndex = 0;
 constexpr int kColorIndex = 1;
 constexpr int kBlendModeIndex = 2;
@@ -29,11 +30,14 @@ constexpr int kFilterQualityIndex = 8;
 constexpr int kColorFilterIndex = 9;
 constexpr int kColorFilterColorIndex = 10;
 constexpr int kColorFilterBlendModeIndex = 11;
-constexpr size_t kDataByteCount = 48;
+constexpr int kMaskFilterIndex = 12;
+constexpr int kMaskFilterBlurStyleIndex = 13;
+constexpr int kMaskFilterSigmaIndex = 14;
+constexpr size_t kDataByteCount = 75;  // 4 * (last index + 1)
 
-constexpr int kMaskFilterIndex = 0;
-constexpr int kShaderIndex = 1;
-constexpr int kObjectCount = 2;  // Must be one larger than the largest index
+// Indices for objects.
+constexpr int kShaderIndex = 0;
+constexpr int kObjectCount = 1;  // One larger than largest object index.
 
 // Must be kept in sync with the default in painting.dart.
 constexpr uint32_t kColorDefault = 0xFF000000;
@@ -46,6 +50,9 @@ constexpr uint32_t kBlendModeDefault =
 // default SkPaintDefaults_MiterLimit in Skia (which is not in a public header).
 constexpr double kStrokeMiterLimitDefault = 4.0;
 
+// Must be kept in sync with the MaskFilter private constants in painting.dart.
+enum MaskFilterType { Null, Blur };
+
 Paint DartConverter<Paint>::FromArguments(Dart_NativeArguments args,
                                           int index,
                                           Dart_Handle& exception) {
@@ -68,12 +75,6 @@ Paint DartConverter<Paint>::FromArguments(Dart_NativeArguments args,
     if (Dart_IsError(Dart_ListGetRange(paint_objects, 0, kObjectCount, values)))
       return result;
 
-    Dart_Handle mask_filter = values[kMaskFilterIndex];
-    if (!Dart_IsNull(mask_filter)) {
-      MaskFilter* decoded = DartConverter<MaskFilter*>::FromDart(mask_filter);
-      paint.setMaskFilter(decoded->filter());
-    }
-
     Dart_Handle shader = values[kShaderIndex];
     if (!Dart_IsNull(shader)) {
       Shader* decoded = DartConverter<Shader*>::FromDart(shader);
@@ -132,6 +133,17 @@ Paint DartConverter<Paint>::FromArguments(Dart_NativeArguments args,
     paint.setColorFilter(SkColorFilter::MakeModeFilter(color, blend_mode));
   }
 
+  switch (uint_data[kMaskFilterIndex]) {
+    case Null:
+      break;
+    case Blur:
+      SkBlurStyle blur_style =
+          static_cast<SkBlurStyle>(uint_data[kMaskFilterBlurStyleIndex]);
+      double sigma = float_data[kMaskFilterSigmaIndex];
+      paint.setMaskFilter(SkBlurMaskFilter::Make(blur_style, sigma));
+      break;
+  }
+
   result.is_null_ = false;
   return result;
 }

testing/run_tests.sh

@@ -6,6 +6,8 @@ out/host_debug_unopt/fxl_unittests
 out/host_debug_unopt/synchronization_unittests
 out/host_debug_unopt/wtf_unittests
 
+flutter/travis/analyze.sh
+
 pushd flutter/testing/dart
 pub get
 popd
@@ -17,3 +19,7 @@ for TEST_SCRIPT in flutter/testing/dart/*.dart; do
     out/host_debug_unopt/flutter_tester --disable-observatory --disable-diagnostic --non-interactive --enable-checked-mode $TEST_SCRIPT
     out/host_debug_unopt/flutter_tester --disable-observatory --disable-diagnostic --non-interactive $TEST_SCRIPT
 done
+
+pushd flutter
+travis/test.sh
+popd

travis/licenses_golden/licenses_flutter

@@ -9509,8 +9509,6 @@ FILE: ../../../flutter/lib/ui/painting/gradient.cc
 FILE: ../../../flutter/lib/ui/painting/gradient.h
 FILE: ../../../flutter/lib/ui/painting/image_shader.cc
 FILE: ../../../flutter/lib/ui/painting/image_shader.h
-FILE: ../../../flutter/lib/ui/painting/mask_filter.cc
-FILE: ../../../flutter/lib/ui/painting/mask_filter.h
 FILE: ../../../flutter/lib/ui/painting/matrix.cc
 FILE: ../../../flutter/lib/ui/painting/matrix.h
 FILE: ../../../flutter/lib/ui/painting/paint.cc