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Color.lerp asserts when mixing Display P3 and sRGB colors in ThemeData/ColorScheme #182777
Description
Steps to reproduce
Use Color.from() with ColorSpace.displayP3 in a ColorScheme and render any widget that internally animates colors (e.g. TextField).
MaterialApp(
theme: ThemeData(
colorScheme: ColorScheme.light(
primary: const Color.from(
alpha: 1,
red: 0.0272,
green: 0.2264,
blue: 0.2928,
colorSpace: ColorSpace.displayP3,
),
),
),
home: const Scaffold(body: TextField()),
)Tap the TextField to trigger focus animation.
Expected results
Color.lerp should handle mixed color spaces gracefully, either by normalizing to a common space before interpolation or by documenting that ColorScheme/ThemeData only supports sRGB.
Actual results
The assertion fires because InputDecorator creates sRGB border colors internally and BorderSide.lerp calls Color.lerp with one sRGB and one Display P3 operand. The same issue affects AnimatedTheme (via ThemeData.lerp), TextStyleTween, ColorTween, and any other framework code that lerps theme-sourced colors against internally-created sRGB colors.
══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
The following assertion was thrown during paint():
'dart:ui/painting.dart': Failed assertion: line 428 pos 16: '<optimized out>': is not true.
Either the assertion indicates an error in the framework itself, or we should provide substantially
more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
https://github.com/flutter/flutter/issues/new?template=02_bug.yml
The relevant error-causing widget was:
TextField TextField:file:///home/spydon/repos/h2-core/app/test/unit/display_p3_repro_test.dart:24:17
When the exception was thrown, this was the stack:
#2 Color.lerp (dart:ui/painting.dart:428:16)
#3 BorderSide.lerp (package:flutter/src/painting/borders.dart:271:22)
#4 UnderlineInputBorder.lerpFrom (package:flutter/src/material/input_border.dart:217:32)
#5 ShapeBorder.lerp (package:flutter/src/painting/borders.dart:516:36)
#6 _InputBorderTween.lerp (package:flutter/src/material/input_decorator.dart:110:45)
#7 Tween.transform (package:flutter/src/animation/tween.dart:369:12)
#8 Animatable.evaluate (package:flutter/src/animation/tween.dart:71:46)
#9 _InputBorderPainter.paint (package:flutter/src/material/input_decorator.dart:140:44)
#10 RenderCustomPaint._paintWithPainter (package:flutter/src/rendering/custom_paint.dart:593:13)
#11 RenderCustomPaint.paint (package:flutter/src/rendering/custom_paint.dart:646:7)
#12 RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3429:7)
#13 PaintingContext.paintChild (package:flutter/src/rendering/object.dart:265:13)
#14 _RenderDecoration.paint.doPaint (package:flutter/src/material/input_decorator.dart:1598:17)
#15 _RenderDecoration.paint (package:flutter/src/material/input_decorator.dart:1602:5)
#16 RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3429:7)
#17 PaintingContext.paintChild (package:flutter/src/rendering/object.dart:265:13)
#18 RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:143:13)
#19 RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3429:7)
#20 PaintingContext.paintChild (package:flutter/src/rendering/object.dart:265:13)
#21 RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:143:13)
#22 RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3429:7)
#23 PaintingContext.paintChild (package:flutter/src/rendering/object.dart:265:13)
#24 RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:143:13)
#25 RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3429:7)
#26 PaintingContext.paintChild (package:flutter/src/rendering/object.dart:265:13)
#27 RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:143:13)
#28 RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3429:7)
#29 PaintingContext.paintChild (package:flutter/src/rendering/object.dart:265:13)
#30 RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:143:13)
#31 RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3429:7)
#32 PaintingContext.paintChild (package:flutter/src/rendering/object.dart:265:13)
#33 RenderBoxContainerDefaultsMixin.defaultPaint (package:flutter/src/rendering/box.dart:3368:15)
#34 RenderCustomMultiChildLayoutBox.paint (package:flutter/src/rendering/custom_layout.dart:422:5)
#35 RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3429:7)
#36 PaintingContext.paintChild (package:flutter/src/rendering/object.dart:265:13)
#37 RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:143:13)
#38 _RenderInkFeatures.paint (package:flutter/src/material/material.dart:634:11)
#39 RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3429:7)
#40 PaintingContext.paintChild (package:flutter/src/rendering/object.dart:265:13)
#41 RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:143:13)
#42 RenderPhysicalModel.paint.<anonymous closure> (package:flutter/src/rendering/proxy_box.dart:2252:15)
#43 PaintingContext.pushClipRRect (package:flutter/src/rendering/object.dart:626:14)
#44 RenderPhysicalModel.paint (package:flutter/src/rendering/proxy_box.dart:2239:21)
#45 RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3429:7)
#46 PaintingContext.paintChild (package:flutter/src/rendering/object.dart:265:13)
#47 RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:143:13)
#48 RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3429:7)
#49 PaintingContext.paintChild (package:flutter/src/rendering/object.dart:265:13)
#50 RenderProxyBoxMixin.paint (package:flutter/src/rendering/proxy_box.dart:143:13)
#51 RenderObject._paintWithContext (package:flutter/src/rendering/object.dart:3429:7)
#52 PaintingContext._repaintCompositedChild (package:flutter/src/rendering/object.dart:180:11)
#53 PaintingContext.repaintCompositedChild (package:flutter/src/rendering/object.dart:125:5)
#54 PipelineOwner.flushPaint (package:flutter/src/rendering/object.dart:1325:31)
#55 PipelineOwner.flushPaint (package:flutter/src/rendering/object.dart:1335:15)
#56 AutomatedTestWidgetsFlutterBinding.drawFrame (package:flutter_test/src/binding.dart:2137:31)
#57 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:495:5)
#58 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1430:15)
#59 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1345:9)
#60 AutomatedTestWidgetsFlutterBinding.pump.<anonymous closure> (package:flutter_test/src/binding.dart:1960:9)
#63 TestAsyncUtils.guard (package:flutter_test/src/test_async_utils.dart:74:41)
#64 AutomatedTestWidgetsFlutterBinding.pump (package:flutter_test/src/binding.dart:1949:27)
#65 WidgetTester.pumpAndSettle.<anonymous closure> (package:flutter_test/src/widget_tester.dart:719:23)
<asynchronous suspension>
#66 TestAsyncUtils.guard.<anonymous closure> (package:flutter_test/src/test_async_utils.dart:130:27)
<asynchronous suspension>
#67 main.<anonymous closure> (file:///home/spydon/repos/h2-core/app/test/unit/display_p3_repro_test.dart:31:5)
<asynchronous suspension>
#68 testWidgets.<anonymous closure>.<anonymous closure> (package:flutter_test/src/widget_tester.dart:192:15)
<asynchronous suspension>
#69 TestWidgetsFlutterBinding._runTestBody (package:flutter_test/src/binding.dart:1682:5)
<asynchronous suspension>
<asynchronous suspension>
(elided 5 frames from class _AssertionError, dart:async, and package:stack_trace)
The following RenderObject was being processed when the exception was fired: RenderCustomPaint#5c433:
creator: CustomPaint ← _BorderContainer ← _Decorator ← InputDecorator ← AnimatedBuilder ← Listener ←
RawGestureDetector ← TextSelectionGestureDetector ← Semantics ← AnimatedBuilder ← IgnorePointer ←
TextFieldTapRegion ← ⋯
parentData: offset=Offset(0.0, 0.0) (can use size)
constraints: BoxConstraints(w=800.0, h=48.0)
size: Size(800.0, 48.0)
painter: null
foregroundPainter: _InputBorderPainter#b661f
This RenderObject has no descendants.
Code sample
Code sample
import 'dart:ui' show ColorSpace;
import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
void main() {
testWidgets('Display P3 color in ColorScheme triggers Color.lerp assert', (
tester,
) async {
await tester.pumpWidget(
MaterialApp(
theme: ThemeData(
colorScheme: ColorScheme.light(
primary: const Color.from(
alpha: 1,
red: 0.0272,
green: 0.2264,
blue: 0.2928,
colorSpace: ColorSpace.displayP3,
),
),
),
home: const Scaffold(
body: TextField(),
),
),
);
// Trigger validation which causes AnimatedDefaultTextStyle to lerp
await tester.tap(find.byType(TextField));
await tester.pumpAndSettle();
});
}
Screenshots or Video
No response
Logs
No response
Flutter Doctor output
Doctor output
I tested both on main and stable with exactly the same results.main:
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel main, 3.42.0-1.0.pre-222, on Ubuntu 24.04.4 LTS 6.8.0-100-generic, locale en_US.UTF-8)
[✓] Android toolchain - develop for Android devices (Android SDK version 36.1.0)
[✓] Chrome - develop for the web
[✓] Linux toolchain - develop for Linux desktop
[✓] Connected device (3 available)
[✓] Network resources
• No issues found!stable:
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 3.41.1, on Ubuntu 24.04.4 LTS 6.8.0-100-generic, locale en_US.UTF-8)
[✓] Android toolchain - develop for Android devices (Android SDK version 36.1.0)
[✓] Chrome - develop for the web
[✓] Linux toolchain - develop for Linux desktop
[✓] Connected device (3 available)
[✓] Network resources
• No issues found!
Activity
mbcorona commentedon Feb 25, 2026
Hi @spydon, thanks for the report and reproducible example! Labeling team-design to take a look at how ThemeData and InputDecorator handle mixed color spaces during lerping.
dkwingsmt commentedon Feb 25, 2026
Sounds like an oversight after adding support for color spaces. If
Color.lerpthrows for mixing color spaces then we should audit all uses ofColor.lerpto eliminate similar errors.spydon commentedon Feb 26, 2026
Can't we just add support for mixed color spaces in
Color.lerpand it'll be automatically solved everywhere?spydon commentedon Feb 26, 2026
I'm thinking that we could just simply do this, what do you think?
Support mixed color spaces in `Color.lerp` (#182934)
Support mixed color spaces in `Color.lerp` (flutter#182934)
github-actions commentedon Mar 17, 2026
This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of
flutter doctor -vand a minimal reproduction of the issue.Support mixed color spaces in `Color.lerp` (flutter#182934)