[WEB] ShaderMask crash

[maxnemoy]

I want to get text with a gradient on web platform

Steps to Reproduce

Widget build(BuildContext context) {
    return ShaderMask(
      shaderCallback: (bounds) => LinearGradient(colors: [
        Colors.blue.shade400,
        Colors.blue.shade900,
      ]).createShader(
        Rect.fromLTWH(0, 0, bounds.width, bounds.height),
      ),
      child: Text(
        text,
        style: TextStyle(
          color: Colors.white,
          fontSize: 40,
        ),
      ),
    );
  }

I get an error

[+1425 ms] ══╡ EXCEPTION CAUGHT BY SCHEDULER LIBRARY ╞═════════════════════════════════════════════════════════

[   +1 ms] The following UnimplementedError was thrown during a scheduler callback:

[   +4 ms] UnimplementedError

[  +22 ms] When the exception was thrown, this was the stack:

[  +13 ms] C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 216:49  throw_

[   +1 ms] C:/b/s/w/ir/cache/builder/src/out/host_debug/flutter_web_sdk/lib/_engine/engine/surface/scene_builder.dart 250:5           pushShaderMask

[  +13 ms] packages/flutter/src/rendering/layer.dart 1856:26                                                                          addToScene

[   +1 ms] packages/flutter/src/rendering/layer.dart 443:5                                                                            [_addToSceneWithRetainedRendering]

[  +14 ms] packages/flutter/src/rendering/layer.dart 1066:14                                                                          addChildrenToScene

[   +1 ms] packages/flutter/src/rendering/layer.dart 2044:5                                                                           addToScene

[   +1 ms] packages/flutter/src/rendering/layer.dart 443:5                                                                            [_addToSceneWithRetainedRendering]

[  +11 ms] packages/flutter/src/rendering/layer.dart 1066:14                                                                          addChildrenToScene

[   +1 ms] packages/flutter/src/rendering/layer.dart 1204:5                                                                           addToScene

[   +1 ms] packages/flutter/src/rendering/layer.dart 443:5                                                                            [_addToSceneWithRetainedRendering]

[   +1 ms] packages/flutter/src/rendering/layer.dart 1066:14                                                                          addChildrenToScene

[  +10 ms] packages/flutter/src/rendering/layer.dart 1204:5                                                                           addToScene

[   +1 ms] packages/flutter/src/rendering/layer.dart 443:5                                                                            [_addToSceneWithRetainedRendering]

[   +1 ms] packages/flutter/src/rendering/layer.dart 1066:14                                                                          addChildrenToScene

[   +1 ms] packages/flutter/src/rendering/layer.dart 1652:5                                                                           addToScene

[        ] packages/flutter/src/rendering/layer.dart 803:5                                                                            buildScene

[   +1 ms] packages/flutter/src/rendering/view.dart 230:36                                                                            compositeFrame

[        ] packages/flutter/src/rendering/binding.dart 406:18                                                                         drawFrame

[        ] packages/flutter/src/widgets/binding.dart 865:13                                                                           drawFrame

[  +10 ms] packages/flutter/src/rendering/binding.dart 284:5                                                                          [_handlePersistentFrameCallback]

[   +1 ms] packages/flutter/src/scheduler/binding.dart 1074:15                                                                        [_invokeFrameCallback]

[   +1 ms] packages/flutter/src/scheduler/binding.dart 1013:9                                                                         handleDrawFrame

[        ] packages/flutter/src/scheduler/binding.dart 822:7                                                                          <fn>

[        ] C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/isolate_helper.dart 50:19       internalCallback

[        ] ════════════════════════════════════════════════════════════════════════════════════════════════════

[   +2 ms] Another exception was thrown: UnimplementedError

i tried using this for windows, it works well

but if not used ShaderMask widget, like a

Text("GRADIENT",
            style: TextStyle(
                fontSize: 90,
                fontWeight: FontWeight.bold,
                foreground: Paint()
                  ..shader = LinearGradient(
                    colors: <Color>[Colors.red, Colors.yellow],
                  ).createShader(Rect.fromLTWH(0.0, 0.0, 1000.0, 90.0)))));
  }

it works correctly

Flutter doctor

flutter doctor -v
[✓] Flutter (Channel master, 1.18.0-13.0.pre.10, on Microsoft Windows [Version 10.0.18363.778], locale ru-RU)
    • Flutter version 1.18.0-13.0.pre.10 at D:\libs\flutter
    • Framework revision 8fbfe1cfbf (10 hours ago), 2020-05-06 17:36:01 -0700
    • Engine revision d6aa099de7
    • Dart version 2.9.0 (build 2.9.0-5.0.dev 4da5b40fb6)

 
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
    • Android SDK at C:\Users\maxne\AppData\Local\Android\sdk
    • Platform android-29, build-tools 29.0.3
    • Java binary at: D:\Program Files\Android\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b04)
    • All Android licenses accepted.

[✓] Chrome - develop for the web
    • Chrome at C:\Program Files (x86)\Google\Chrome\Application\chrome.exe

[✓] Visual Studio - develop for Windows (Visual Studio CommunityВ 2019 16.5.1)
    • Visual Studio at D:\Program Files (x86)\Microsoft Visual Studio\2019\Community
    • Visual Studio CommunityВ 2019 version 16.5.29920.165

[✓] Android Studio (version 3.6)
    • Android Studio at D:\Program Files\Android\Android Studio
    • Flutter plugin version 44.0.2
    • Dart plugin version 192.7761
    • Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b04)

[✓] Connected device (3 available)
    • Windows    • Windows    • windows-x64    • Microsoft Windows [Version 10.0.18363.778]
    • Web Server • web-server • web-javascript • Flutter Tools
    • Chrome     • chrome     • web-javascript • Google Chrome 81.0.4044.138

UPD:

Rect.fromLTWH works correctly only when turned on debug paint mode

[TahaTesser]

Hi @maxnemoy
Looks like ShaderMask isn't supported on web, put thumbs up emoji on mentioned issue
Closing as duplicate of #44152
Thank you

[github-actions]

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