fix: mask disappeared when having nested mask filter on Flutter web HTML

[Kingtous]

Hi from Dora team, which powers web developers to build their 3d websites in just a few seconds.

This PR fixes: flutter/flutter#133443, related: flutter/flutter#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.

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Golden file changes have been found for this pull request. Click here to view and triage (e.g. because this is an intentional change).

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Changes reported for pull request #45166 at sha 9c48c87

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Changes reported for pull request #45166 at sha f22f02e

[Kingtous]

Any updates here? :)

[flutter-dashboard]

This pull request executed golden file tests, but it has not been updated in a while (20+ days). Test results from Gold expire after as many days, so this pull request will need to be updated with a fresh commit in order to get results from Gold.

[harryterkelsen]

Hi, just seeing this now. I am looking into image filters right now and will look into this tomorrow.

[harryterkelsen]

LGTM. Sorry for the delay in review, I am making it a priority going forward to review third-party contributions.

Please rebase on top of main so the golden tests aren't polluted with all the new goldens that have been added since this PR was created.

Again, thanks so much! External contributors like you make Flutter great!

[harryterkelsen]

Hello @Kingtous, do you plan to rebase this PR on the latest main commit to fix the goldens? Thanks

[Kingtous]

Hello @Kingtous, do you plan to rebase this PR on the latest main commit to fix the goldens? Thanks

Sure, I'll rebase this PR to the latest main commit these days. Thanks for reviewing this PR :)

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Golden file changes are available for triage from new commit, Click here to view.

Changes reported for pull request #45166 at sha d4c7c4e

[Kingtous]

Hello @Kingtous, do you plan to rebase this PR on the latest main commit to fix the goldens? Thanks

Done.

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Golden file changes are available for triage from new commit, Click here to view.

Changes reported for pull request #45166 at sha 3528c73

[harryterkelsen]

I'm updating the branch to determine up-to-date golden file changes

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Golden file changes are available for triage from new commit, Click here to view.

Changes reported for pull request #45166 at sha 9f44c8f

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Golden file changes are available for triage from new commit, Click here to view.

Changes reported for pull request #45166 at sha a29b7b4

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auto label is removed for flutter/engine/45166, due to This PR has not met approval requirements for merging. The PR author is not a member of flutter-hackers and needs 1 more review(s) in order to merge this PR.

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[yjbanov]

[jiahaog]

Reason for revert: 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:

Code

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(useMaterial3: false),
      title: 'Flutter Demo',
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title, style: TextStyle(fontFamily: 'ProductSans')),
      ),
      body: Center(
        child: Text(
          'Button tapped $_counter time${_counter == 1 ? '' : 's'}.',
          key: Key('CountText'),
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ),
    );
  }
}

Screenshots:

Before this change

After this change

Observe that the debug banner on the top right is now blurred. This test runs on Chrome Linux v126, and the unexpected blurs can be seen in both DDC and Dart2js mode with the html renderer.

This can also be reproduced with a fresh flutter app in chrome v126 with the following command on linux (didn't check other platforms), with a Flutter checkout at flutter/flutter@fa70e61. It does not reproduce with the parent commit, nor with the --web-renderer argument ommited.

flutter run web -d chrome --web-renderer html

Googlers, see b/351082848 for more details.