From a918c608b85a110630e5c8df1fa1ed9c49d7ca88 Mon Sep 17 00:00:00 2001
From: "auto-submit[bot]" <98614782+auto-submit[bot]@users.noreply.github.com>
Date: Thu, 4 Jul 2024 07:04:25 +0000
Subject: [PATCH] Reverts "fix: mask disappeared when having nested mask filter
 on Flutter web HTML (#45166)" (flutter/engine#53725)

Reverts: flutter/engine#45166
Initiated by: jiahaog
Reason for reverting: This commit seems to cause the debug banner of a material app to be unnecessarily blurred. For example, one of the tests runs the following flutter app:

<details>

<summary>Code</summary>

```dart
import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Materia
Original PR Author: Kingtous

Reviewed By: {yjbanov, harryterkelsen}

This change reverts the following previous change:
Hi from [Dora team](https://www.dora.run/), which powers web developers to build their 3d websites in just a few seconds.

This PR fixes: https://github.com/flutter/flutter/issues/133443, related: https://github.com/flutter/flutter/issues/58546

The original codes attempts to cache the css string but it causes bugs when encountering nested the same mask filter blur. We should also set `filter` properties when currentFilter == incoming mask filter using the cached css string, not just ignore it.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
---
 .../web_ui/lib/src/engine/canvas_pool.dart    | 28 ++++++++--------
 .../canvas_mask_filter_golden_test.dart       | 32 -------------------
 2 files changed, 13 insertions(+), 47 deletions(-)

diff --git a/engine/src/flutter/lib/web_ui/lib/src/engine/canvas_pool.dart b/engine/src/flutter/lib/web_ui/lib/src/engine/canvas_pool.dart
index 4fbc1eecf2..2fb4ad478b 100644
--- a/engine/src/flutter/lib/web_ui/lib/src/engine/canvas_pool.dart
+++ b/engine/src/flutter/lib/web_ui/lib/src/engine/canvas_pool.dart
@@ -934,7 +934,6 @@ class ContextStateHandle {
   }
 
   ui.MaskFilter? _currentFilter;
-  String? _currentFilterCss;
   SurfacePaintData? _lastUsedPaint;
 
   /// Currently active shader bounds.
@@ -1004,20 +1003,19 @@ class ContextStateHandle {
     }
 
     final ui.MaskFilter? maskFilter = paint.maskFilter;
-    if (maskFilter != null) {
-      if (!_renderMaskFilterForWebkit) {
-        if (_currentFilter != maskFilter) {
-          _currentFilter = maskFilter;
-          _currentFilterCss = maskFilterToCanvasFilter(maskFilter);
-        }
-        context.filter = _currentFilterCss;
-      } else {
-        // WebKit does not support the `filter` property. Instead we apply a
-        // shadow to the shape of the same color as the paint and the same blur
-        // as the mask filter.
-        //
-        // Note that on WebKit the cached value of _currentFilter is not useful.
-        // Instead we destructure it into the shadow properties and cache those.
+    if (!_renderMaskFilterForWebkit) {
+      if (_currentFilter != maskFilter) {
+        _currentFilter = maskFilter;
+        context.filter = maskFilterToCanvasFilter(maskFilter);
+      }
+    } else {
+      // WebKit does not support the `filter` property. Instead we apply a
+      // shadow to the shape of the same color as the paint and the same blur
+      // as the mask filter.
+      //
+      // Note that on WebKit the cached value of _currentFilter is not useful.
+      // Instead we destructure it into the shadow properties and cache those.
+      if (maskFilter != null) {
         context.save();
         context.shadowBlur = convertSigmaToRadius(maskFilter.webOnlySigma);
         // Shadow color must be fully opaque.
diff --git a/engine/src/flutter/lib/web_ui/test/html/compositing/canvas_mask_filter_golden_test.dart b/engine/src/flutter/lib/web_ui/test/html/compositing/canvas_mask_filter_golden_test.dart
index e38aa59726..840bb0c233 100644
--- a/engine/src/flutter/lib/web_ui/test/html/compositing/canvas_mask_filter_golden_test.dart
+++ b/engine/src/flutter/lib/web_ui/test/html/compositing/canvas_mask_filter_golden_test.dart
@@ -150,38 +150,6 @@ Future<void> testMain() async {
       await canvasScreenshot(rc, 'mask_filter_transformed_$browser',
           region: screenRect);
     });
-
-    test('multiple MaskFilter.blur in $browser', () async {
-      const double screenWidth = 300.0;
-      const double screenHeight = 300.0;
-      const ui.Rect screenRect =
-          ui.Rect.fromLTWH(0, 0, screenWidth, screenHeight);
-
-      ContextStateHandle.debugEmulateWebKitMaskFilter = isWebkit;
-      final RecordingCanvas rc = RecordingCanvas(screenRect);
-
-      final SurfacePaint paint = SurfacePaint()
-        ..maskFilter = const ui.MaskFilter.blur(ui.BlurStyle.normal, 5);
-      rc.save();
-      rc.drawCircle(const ui.Offset(150, 150), 100,
-          paint..color = const ui.Color(0xFFC8C800));
-      rc.restore();
-      rc.save();
-      rc.drawCircle(const ui.Offset(150, 150), 50,
-          paint..color = const ui.Color(0xFFC800C8));
-      rc.restore();
-      rc.save();
-      rc.drawCircle(
-          const ui.Offset(150, 150),
-          20,
-          paint
-            ..color = const ui.Color(0xFF00C8C8)
-            ..maskFilter = const ui.MaskFilter.blur(ui.BlurStyle.normal, 10));
-      rc.restore();
-
-      await canvasScreenshot(rc, 'multiple_mask_filter_$browser',
-          region: screenRect);
-    });
   }
 
   testMaskFilterBlur();