[framework] lerp images in a save layer. (#131703)
Without a saveLayer, the BlendMode.plus will add itself to the backdrop and not just the previous image. Pushing without tests to see if existing goldens fail, but otherwise I have some good examples locally.
This is necessary uncondtionally, and lerping lerped images has the same issue.
Fixes https://github.com/flutter/flutter/issues/131617
### Before
### After
diff --git a/packages/flutter/lib/src/painting/decoration_image.dart b/packages/flutter/lib/src/painting/decoration_image.dart
index c91a9f0..66c1be2 100644
--- a/packages/flutter/lib/src/painting/decoration_image.dart
+++ b/packages/flutter/lib/src/painting/decoration_image.dart
@@ -815,8 +815,10 @@
@override
void paint(Canvas canvas, Rect rect, Path? clipPath, ImageConfiguration configuration, { double blend = 1.0, BlendMode blendMode = BlendMode.srcOver }) {
+ canvas.saveLayer(null, Paint());
a?.paint(canvas, rect, clipPath, configuration, blend: blend * (1.0 - t), blendMode: blendMode);
b?.paint(canvas, rect, clipPath, configuration, blend: blend * t, blendMode: a != null ? BlendMode.plus : blendMode);
+ canvas.restore();
}
@override
diff --git a/packages/flutter/test/painting/decoration_image_lerp_test.dart b/packages/flutter/test/painting/decoration_image_lerp_test.dart
index 1e0f6f4..44d2e3e 100644
--- a/packages/flutter/test/painting/decoration_image_lerp_test.dart
+++ b/packages/flutter/test/painting/decoration_image_lerp_test.dart
@@ -405,6 +405,169 @@
expect(getPixelFromBlock(19, 19, 19), const Color(0xFF000000));
}
}, skip: kIsWeb); // TODO(ianh): https://github.com/flutter/flutter/issues/130612, https://github.com/flutter/flutter/issues/130609
+
+ testWidgets('ImageDecoration.lerp with colored background', (WidgetTester tester) async {
+ final MemoryImage cmyk = MemoryImage(Uint8List.fromList(<int>[
+ 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d, 0x49, 0x48, 0x44, 0x52,
+ 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x04, 0x02, 0x03, 0x00, 0x00, 0x00, 0xd4, 0x9f, 0x76,
+ 0xed, 0x00, 0x00, 0x00, 0x0c, 0x50, 0x4c, 0x54, 0x45, 0x00, 0xff, 0xff, 0xff, 0x00, 0xff, 0xff,
+ 0xff, 0x00, 0x00, 0x00, 0x00, 0x3b, 0x4c, 0x59, 0x13, 0x00, 0x00, 0x00, 0x0e, 0x49, 0x44, 0x41,
+ 0x54, 0x08, 0xd7, 0x63, 0x60, 0x05, 0xc2, 0xf5, 0x0c, 0xeb, 0x01, 0x03, 0x00, 0x01, 0x69, 0x19,
+ 0xea, 0x34, 0x7b, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4e, 0x44, 0xae, 0x42, 0x60, 0x82,
+ ]));
+ final MemoryImage wrgb = MemoryImage(Uint8List.fromList(<int>[
+ 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d, 0x49, 0x48, 0x44, 0x52,
+ 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x04, 0x02, 0x03, 0x00, 0x00, 0x00, 0xd4, 0x9f, 0x76,
+ 0xed, 0x00, 0x00, 0x00, 0x0c, 0x50, 0x4c, 0x54, 0x45, 0xff, 0xff, 0xff, 0x00, 0x00, 0xff, 0x00,
+ 0xff, 0x00, 0xff, 0x00, 0x00, 0x1e, 0x46, 0xbb, 0x1c, 0x00, 0x00, 0x00, 0x0e, 0x49, 0x44, 0x41,
+ 0x54, 0x08, 0xd7, 0x63, 0xe0, 0x07, 0xc2, 0xa5, 0x0c, 0x4b, 0x01, 0x03, 0x50, 0x01, 0x69, 0x4a,
+ 0x78, 0x1d, 0x41, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4e, 0x44, 0xae, 0x42, 0x60, 0x82,
+ ]));
+
+ await tester.runAsync(() async {
+ await load(cmyk);
+ await load(wrgb);
+ });
+
+ await tester.pumpWidget(
+ ColoredBox(
+ color: Colors.pink,
+ child: Align(
+ alignment: Alignment.topLeft,
+ child: Wrap(
+ textDirection: TextDirection.ltr,
+ children: <Widget>[
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, fit: BoxFit.contain),
+ DecorationImage(image: cmyk, fit: BoxFit.contain),
+ 0.0,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, fit: BoxFit.contain),
+ DecorationImage(image: cmyk, fit: BoxFit.contain),
+ 0.1,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, fit: BoxFit.contain),
+ DecorationImage(image: cmyk, fit: BoxFit.contain),
+ 0.2,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, fit: BoxFit.contain),
+ DecorationImage(image: cmyk, fit: BoxFit.contain),
+ 0.5,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, fit: BoxFit.contain),
+ DecorationImage(image: cmyk, fit: BoxFit.contain),
+ 0.8,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, fit: BoxFit.contain),
+ DecorationImage(image: cmyk, fit: BoxFit.contain),
+ 0.9,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, fit: BoxFit.contain),
+ DecorationImage(image: cmyk, fit: BoxFit.contain),
+ 1.0,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, fit: BoxFit.cover),
+ DecorationImage(image: cmyk, repeat: ImageRepeat.repeat),
+ 0.5,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, repeat: ImageRepeat.repeat),
+ DecorationImage(image: cmyk, repeat: ImageRepeat.repeatY),
+ 0.5,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, repeat: ImageRepeat.repeatX),
+ DecorationImage(image: cmyk, repeat: ImageRepeat.repeat),
+ 0.5,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, repeat: ImageRepeat.repeat, opacity: 0.2),
+ DecorationImage(image: cmyk, repeat: ImageRepeat.repeat, opacity: 0.2),
+ 0.25,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, repeat: ImageRepeat.repeat, opacity: 0.2),
+ DecorationImage(image: cmyk, repeat: ImageRepeat.repeat, opacity: 0.2),
+ 0.5,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, repeat: ImageRepeat.repeat, opacity: 0.2),
+ DecorationImage(image: cmyk, repeat: ImageRepeat.repeat, opacity: 0.2),
+ 0.75,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: wrgb, scale: 0.5, repeat: ImageRepeat.repeatX),
+ DecorationImage(image: cmyk, scale: 0.25, repeat: ImageRepeat.repeatY),
+ 0.5,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ 0.0,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ 0.25,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ 0.5,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ 0.75,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ 1.0,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(0.0, 0.0, 1.0, 1.0)),
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ 0.0,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(0.0, 0.0, 1.0, 1.0)),
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ 0.25,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(0.0, 0.0, 1.0, 1.0)),
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ 0.5,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(0.0, 0.0, 1.0, 1.0)),
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ 0.75,
+ )),
+ TestImage(DecorationImage.lerp(
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(0.0, 0.0, 1.0, 1.0)),
+ DecorationImage(image: cmyk, centerSlice: const Rect.fromLTWH(2.0, 2.0, 1.0, 1.0)),
+ 1.0,
+ )),
+ ],
+ ),
+ ),
+ ),
+ );
+
+ await expectLater(
+ find.byType(Wrap),
+ matchesGoldenFile('decoration_image.lerp.2.png'),
+ );
+ }, skip: kIsWeb); // TODO(ianh): https://github.com/flutter/flutter/issues/130612, https://github.com/flutter/flutter/issues/130609
}
Future<void> load(MemoryImage image) {
