From 1e2583eff25200b10f01d1fc2d13e7936fba57d2 Mon Sep 17 00:00:00 2001
From: Jonah Williams <jonahwilliams@google.com>
Date: Mon, 24 Feb 2025 11:01:55 -0800
Subject: [PATCH] [ui] Fix ImageFilter.shader equality to consider uniform
values. (#163348)
Fixes https://github.com/flutter/flutter/issues/163302
Framework widgets check for ImageFIlter.== to determine whether to mark
themselves dirty. The filter obejct needs to delegate its equality to
the underlying native filter so that uniform values are considered.
---
engine/src/flutter/lib/ui/dart_ui.cc | 1 +
engine/src/flutter/lib/ui/painting.dart | 7 ++++-
.../flutter/lib/ui/painting/image_filter.cc | 4 +++
.../flutter/lib/ui/painting/image_filter.h | 1 +
.../testing/dart/fragment_shader_test.dart | 28 +++++++++++++++++++
5 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/engine/src/flutter/lib/ui/dart_ui.cc b/engine/src/flutter/lib/ui/dart_ui.cc
index a47bf094c42..7bb1aef0ede 100644
--- a/engine/src/flutter/lib/ui/dart_ui.cc
+++ b/engine/src/flutter/lib/ui/dart_ui.cc
@@ -207,6 +207,7 @@ typedef CanvasPath Path;
V(ImageFilter, initComposeFilter) \
V(ImageFilter, initShader) \
V(ImageFilter, initMatrix) \
+ V(ImageFilter, equals) \
V(ImageShader, dispose) \
V(ImageShader, initWithImage) \
V(ImmutableBuffer, dispose) \
diff --git a/engine/src/flutter/lib/ui/painting.dart b/engine/src/flutter/lib/ui/painting.dart
index dea0c7885fa..ddda85d2752 100644
--- a/engine/src/flutter/lib/ui/painting.dart
+++ b/engine/src/flutter/lib/ui/painting.dart
@@ -4474,9 +4474,14 @@ class _FragmentShaderImageFilter implements ImageFilter {
if (other.runtimeType != runtimeType) {
return false;
}
- return other is _FragmentShaderImageFilter && other.shader == shader;
+ return other is _FragmentShaderImageFilter &&
+ other.shader == shader &&
+ _equals(nativeFilter, other.nativeFilter);
}
+ @Native<Bool Function(Handle, Handle)>(symbol: 'ImageFilter::equal')
+ external static bool _equals(_ImageFilter a, _ImageFilter b);
+
@override
int get hashCode => shader.hashCode;
}
diff --git a/engine/src/flutter/lib/ui/painting/image_filter.cc b/engine/src/flutter/lib/ui/painting/image_filter.cc
index 2319008bc4f..8d21d638847 100644
--- a/engine/src/flutter/lib/ui/painting/image_filter.cc
+++ b/engine/src/flutter/lib/ui/painting/image_filter.cc
@@ -125,4 +125,8 @@ void ImageFilter::initShader(ReusableFragmentShader* shader) {
filter_ = shader->as_image_filter();
}
+bool ImageFilter::equals(ImageFilter* a, ImageFilter* b) {
+ return a->filter_ == b->filter_;
+}
+
} // namespace flutter
diff --git a/engine/src/flutter/lib/ui/painting/image_filter.h b/engine/src/flutter/lib/ui/painting/image_filter.h
index c7bb6369bdb..c251d9653f6 100644
--- a/engine/src/flutter/lib/ui/painting/image_filter.h
+++ b/engine/src/flutter/lib/ui/painting/image_filter.h
@@ -36,6 +36,7 @@ class ImageFilter : public RefCountedDartWrappable<ImageFilter> {
void initColorFilter(ColorFilter* colorFilter);
void initComposeFilter(ImageFilter* outer, ImageFilter* inner);
void initShader(ReusableFragmentShader* shader);
+ bool equals(ImageFilter* a, ImageFilter* b);
const std::shared_ptr<DlImageFilter> filter(DlTileMode mode) const;
diff --git a/engine/src/flutter/testing/dart/fragment_shader_test.dart b/engine/src/flutter/testing/dart/fragment_shader_test.dart
index 0bfffbf515d..54366f7af2a 100644
--- a/engine/src/flutter/testing/dart/fragment_shader_test.dart
+++ b/engine/src/flutter/testing/dart/fragment_shader_test.dart
@@ -415,6 +415,34 @@ void main() async {
expect(color, const Color(0xFF00FF00));
});
+ // For an explaination of the problem see https://github.com/flutter/flutter/issues/163302 .
+ test('ImageFilter.shader equality checks consider uniform values', () async {
+ if (!impellerEnabled) {
+ print('Skipped for Skia');
+ return;
+ }
+ final FragmentProgram program = await FragmentProgram.fromAsset('filter_shader.frag.iplr');
+ final FragmentShader shader = program.fragmentShader();
+ final ImageFilter filter = ImageFilter.shader(shader);
+
+ // The same shader is equal to itself.
+ expect(filter, filter);
+ expect(identical(filter, filter), true);
+
+ final ImageFilter filter_2 = ImageFilter.shader(shader);
+
+ // The different shader is equal as long as uniforms are identical.
+ expect(filter, filter_2);
+ expect(identical(filter, filter_2), false);
+
+ // Not equal if uniforms change.
+ shader.setFloat(0, 1);
+ final ImageFilter filter_3 = ImageFilter.shader(shader);
+
+ expect(filter, isNot(filter_3));
+ expect(identical(filter, filter_3), false);
+ });
+
if (impellerEnabled) {
print('Skipped for Impeller - https://github.com/flutter/flutter/issues/122823');
return;
--
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