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@gaaclarke gaaclarke commented Feb 11, 2025

This is a cherry-pick for all the changes that went into fixing #149652

It looks like a lot but most of it is testing and refactoring.

PRs included

Impacted Users

All users of Impeller.

Impact Description

Animating text with translations and scales can cause:

  • jitter between glyphs
  • jitter between glyphs and the baseline
  • artifacts when rendering glyphs at non integer scales

Workaround

Use skia.

Risk

Since this edits how text is rendered, the risk is pretty high. The actual changes are small and there are unit tests for them. Golden test coverage for cherry-picks is not complete and text rendering golden coverage for android is problematic.

Test Coverage

Yes.

Validation Steps

The reproduction code in #149652 is good.

Pre-launch Checklist

If you need help, consider asking for advice on the #hackers-new channel on Discord.

gaaclarke and others added 6 commits February 11, 2025 09:15
issue: flutter#149652

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

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[Contributor Guide]:
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[Tree Hygiene]:
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[Flutter Style Guide]:
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[Features we expect every widget to implement]:
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[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
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[Discord]:
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[Data Driven Fixes]:
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issue: flutter#149652

Animating from 0.444x to 0.445x

![before-pos](https://github.com/user-attachments/assets/3b561e35-68ca-49ca-aa3e-e2c224ae06c5)

Animating from 0.444x to 0.445x

![after-pos](https://github.com/user-attachments/assets/3ef67ec9-29ce-481a-83ff-cb27fbe2ddca)

Diff at 0.444x

![444](https://github.com/user-attachments/assets/2a309f2d-65ad-4be2-bc35-7b9df5639c0f)

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
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[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
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[Discord]:
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[Data Driven Fixes]:
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fixes flutter#162348

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
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[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
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issue: flutter#149652

This makes flutter#149652 better. It
doesn't completely it better though, there is still a shrinking of
whitespace at larger scales. Without this patch though the test will
fail with many 3 pixel jumps between glyphs.

I think scaling in the thousands is reasonable so this is an adequate
test.

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
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[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md
fixes flutter#162776
fixes flutter#149652

Previously we weren't calculating the subpixel offset correctly. We
weren't using the transform of the object being drawn to get global
coordinates, now we are.

## Video of flutter#149652 after PR



https://github.com/user-attachments/assets/3e9063d5-f70c-46d0-a7a4-892819b247b8



## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
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[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
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@github-actions github-actions bot added a: text input Entering text in a text field or keyboard related problems engine flutter/engine related. See also e: labels. e: impeller Impeller rendering backend issues and features requests labels Feb 11, 2025
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@jonahwilliams isn't there a special label I have to put on this PR? I'm not seeing anything in the cherry-pick doc.

@jonahwilliams jonahwilliams added the cp: beta cherry pick this pull request to beta release candidate branch label Feb 11, 2025
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🤷

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LGTM!

@gaaclarke gaaclarke added the cp: review Cherry-picks in the review queue label Feb 12, 2025
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FYI @zanderso

@zanderso zanderso added the cp: approved Approved cherry-pick request label Feb 12, 2025
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CP LGTM. The number of files is a little misleading since the change includes some new testing logic, a bunch of new unit tests, and some code moving between files.

@christopherfujino christopherfujino added cp: stable cherry pick this pull request to stable release candidate branch and removed cp: beta cherry pick this pull request to beta release candidate branch labels Feb 13, 2025
@eyebrowsoffire eyebrowsoffire added the autosubmit Merge PR when tree becomes green via auto submit App label Feb 20, 2025
@auto-submit auto-submit bot merged commit d73fc34 into flutter:flutter-3.29-candidate.0 Feb 20, 2025
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engine-flutter-autoroll added a commit to engine-flutter-autoroll/packages that referenced this pull request Mar 6, 2025
engine-flutter-autoroll added a commit to engine-flutter-autoroll/packages that referenced this pull request Mar 7, 2025
@reidbaker reidbaker mentioned this pull request Apr 4, 2025
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Fintasys pushed a commit to Fintasys/flutter that referenced this pull request May 14, 2025
This is a cherry-pick for all the changes that went into fixing flutter#149652

It looks like a lot but most of it is testing and refactoring.

- flutter#161625
- flutter#162351
- flutter#162415
- flutter#162555
- flutter#162824

All users of Impeller.

Animating text with translations and scales can cause:
  - jitter between glyphs
  - jitter between glyphs and the baseline
  - artifacts when rendering glyphs at non integer scales

Use skia.

Since this edits how text is rendered, the risk is pretty high.  The actual changes are small and there are unit tests for them.  Golden test coverage for cherry-picks is not complete and text rendering golden coverage for android is problematic.

Yes.

The reproduction code in flutter#149652 is good.
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a: text input Entering text in a text field or keyboard related problems autosubmit Merge PR when tree becomes green via auto submit App cp: approved Approved cherry-pick request cp: review Cherry-picks in the review queue cp: stable cherry pick this pull request to stable release candidate branch e: impeller Impeller rendering backend issues and features requests engine flutter/engine related. See also e: labels.

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5 participants