签名板在 flutter web 中不起作用？

Question

我正在使用

syncfusion_flutter_signaturepad: ^21.1.35

从用户那里获取签名。它在 flutter 移动应用程序中运行良好，但在 flutter web 中运行不正常。

似乎

toImage()

在网络上不受支持，或者我做错了什么。

保存图像代码：

final GlobalKey<SfSignaturePadState> signaturePadKey = GlobalKey<SfSignaturePadState();
ui.Image data = await signaturePadKey.currentState!.toImage(pixelRatio: 3.0);
ByteData? bytes = await data.toByteData(format: ui.ImageByteFormat.png);
String imageEncoded = base64.encode(bytes!.buffer.asUint8List());

Error: Assertion failed: org-dartlang-sdk:///flutter_web_sdk/lib/_engine/engine/html/scene_builder.dart:94:16 dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 266:49      throw_ dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 29:3        assertFailed lib/_engine/engine/html/scene_builder.dart 95:34                                  pushTransform packages/flutter/src/rendering/layer.dart 1414:12                                 toImage dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 84:54                runBody dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 123:5                _async packages/flutter/src/rendering/layer.dart 1404:27                                 toImage packages/syncfusion_flutter_signaturepad/signaturepad.dart 974:13                 toImage dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 84:54                runBody dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 123:5                _async packages/syncfusion_flutter_signaturepad/signaturepad.dart 972:27                 toImage packages/syncfusion_flutter_signaturepad/signaturepad.dart 372:31                 toImage packages/tolk2go_tasker/SignaturePage/signature_view_model.dart 33:33             validatingSignature dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 84:54                runBody dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 123:5                _async packages/tolk2go_tasker/SignaturePage/signature_view_model.dart 28:35             validatingSignature packages/tolk2go_tasker/SignaturePage/signature.dart 156:54                       <fn> packages/flutter/src/material/ink_well.dart 1072:21                               handleTap packages/flutter/src/gestures/recognizer.dart 253:24                              invokeCallback packages/flutter/src/gestures/tap.dart 627:11                                     handleTapUp packages/flutter/src/gestures/tap.dart 306:5                                      [_checkUp] packages/flutter/src/gestures/tap.dart 239:7                                      handlePrimaryPointer packages/flutter/src/gestures/recognizer.dart 615:9                               handleEvent packages/flutter/src/gestures/pointer_router.dart 98:12                           [_dispatch] packages/flutter/src/gestures/pointer_router.dart 143:9                           <fn> dart-sdk/lib/_internal/js_dev_runtime/private/linked_hash_map.dart 21:13          forEach packages/flutter/src/gestures/pointer_router.dart 141:17                          [_dispatchEventToRoutes] packages/flutter/src/gestures/pointer_router.dart 127:7                           route packages/flutter/src/gestures/binding.dart 460:19                                 handleEvent packages/flutter/src/gestures/binding.dart 440:14                                 dispatchEvent packages/flutter/src/rendering/binding.dart 337:11                                dispatchEvent packages/flutter/src/gestures/binding.dart 395:7                                  [_handlePointerEventImmediately] packages/flutter/src/gestures/binding.dart 357:5                                  handlePointerEvent packages/flutter/src/gestures/binding.dart 314:7                                  [_flushPointerEventQueue] packages/flutter/src/gestures/binding.dart 295:7                                  [_handlePointerDataPacket] lib/_engine/engine/platform_dispatcher.dart 1183:13                               invoke1 lib/_engine/engine/platform_dispatcher.dart 244:5                                 invokeOnPointerDataPacket lib/_engine/engine/pointer_binding.dart 147:39                                    [_onPointerData] lib/_engine/engine/pointer_binding.dart 653:20                                    <fn> lib/_engine/engine/pointer_binding.dart 594:14                                    <fn> lib/_engine/engine/pointer_binding.dart 288:16                                    loggedHandler lib/_engine/engine/pointer_binding.dart 179:80                                    <fn> dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 334:14  _checkAndCall dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 339:39  dcall

颤振医生：

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    • Dart version 2.19.5
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