8356320: GifImageDecoder can produce wrong image when GCE changes transparent pixel index #25076

mickleness · 2025-05-07T02:55:12Z

When a gif frame's disposal code is DISPOSAL_BGCOLOR and we're maintaining a saved image: we have to flood-fill the frame's bounds. And if the transparent pixel index changes across frames: we could sometimes flood fill the wrong value, resulting in an opaque rectangle in the output image.

There are a cluster of four related PRs that share the GifComparison class in this PR.

~~8357034~~ (integrated)
~~8356137~~ (integrated)
~~8356320~~ (this one; cannot repro after merging first two)
8351913

The test in this PR required 8356137's PR to pass.

This bug can be observed reading this gif animation:
https://tenor.com/view/fnf-free-download-fnf-free-download-fnf-fd-cyan-gif-15334412416964826224

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Issue

JDK-8356320: GifImageDecoder can produce wrong image when GCE changes transparent pixel index (Bug - P4)

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Jayathirth D V (@jayathirthrao - Reviewer)

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$ git fetch https://git.openjdk.org/jdk.git pull/25076/head:pull/25076
$ git checkout pull/25076

Update a local copy of the PR:
$ git checkout pull/25076
$ git pull https://git.openjdk.org/jdk.git pull/25076/head

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$ git pr checkout 25076

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Merge openjdk/jdk into mickleness/jdk

Merge openjdk/jdk

Merge from openjdk/jdk

Updating mickleness/jdk from openjdk/jdk

updating to openjdk/jdk

In this ticket the problem was: `tpix` was the transparent pixel index of the current `model`. However `decoder.saved_image` uses its own IndexColorModel (see `decoder.saved_model`). In a simple gif these two models are the same, but in this case the gif has some frames that change the transparent pixel index between frames. We were filling the wrong tpix value, resulting in an opaque rectangle.

bridgekeeper · 2025-05-07T02:55:59Z

👋 Welcome back mickleness! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

openjdk · 2025-05-07T02:56:56Z

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

openjdk · 2025-05-07T02:57:28Z

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mlbridge · 2025-05-07T03:01:03Z

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openjdk · 2025-05-26T05:28:58Z

⚠️ @mickleness This pull request contains merges that bring in commits not present in the target repository. Since this is not a "merge style" pull request, these changes will be squashed when this pull request in integrated. If this is your intention, then please ignore this message. If you want to preserve the commit structure, you must change the title of this pull request to Merge <project>:<branch> where <project> is the name of another project in the OpenJDK organization (for example Merge jdk:master).

This makes the main() method much less useful, so I removed it too. (I originally used this class to explore a folder of hundreds of gifs to look for discrepancies. But the discrepancies were rarely only on the last frame.) This is in response to: openjdk#25044 (comment)

This can be used by multiple gif tests in this directory. This is in response to: openjdk#25044 (review)

This is an extension of work for this PR: openjdk#25044 (review)

openjdk · 2025-07-11T18:54:17Z

@mickleness this pull request can not be integrated into master due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

git checkout JDK-8356320
git fetch https://git.openjdk.org/jdk.git master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

# Conflicts: # test/jdk/sun/awt/image/gif/GifBuilder.java # test/jdk/sun/awt/image/gif/GifComparison.java

mickleness · 2025-07-11T22:00:22Z

I merged with master and confirmed the unit test passes and the original sample gif (fnf-free-download in PR description) passes.

jayathirthrao · 2025-08-04T07:31:05Z

/reviewers 2 reviewer

openjdk · 2025-08-04T07:32:37Z

@jayathirthrao
The total number of required reviews for this PR (including the jcheck configuration and the last /reviewers command) is now set to 2 (with at least 2 Reviewers).

jayathirthrao

Code change looks good to me.
CI testing is green.

Please update the test to include image dumping logic for debugging.

mickleness · 2025-08-04T16:59:29Z

Regarding the image dumping logic: that will (mostly) automatically appear once we merge #25264 (specifically b418a02 ). I'll remove rfr for now until that ticket is merged.

jayathirthrao · 2025-08-20T04:37:59Z

Regarding the image dumping logic: that will (mostly) automatically appear once we merge #25264 (specifically b418a02 ). I'll remove rfr for now until that ticket is merged.

Sure, while testing this PR i manually took debugging logic and tested.

bridgekeeper · 2025-10-15T15:42:30Z

@mickleness This pull request has been inactive for more than 8 weeks and will be automatically closed if another 8 weeks passes without any activity. To avoid this, simply issue a /touch or /keepalive command to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

mickleness · 2025-11-06T05:40:26Z

Closing. I believe https://github.com/openjdk/jdk/pull/25264/files resolved this. See https://bugs.openjdk.org/browse/JDK-8356320?focusedCommentId=14831492&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14831492

mickleness and others added 14 commits May 22, 2022 04:50

Merge pull request #1 from openjdk/master

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Merge pull request #4 from openjdk/master

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Updating mickleness/jdk from openjdk/jdk

Merge pull request #5 from openjdk/master

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updating to openjdk/jdk

Merge branch 'openjdk:master' into master

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Merge branch 'openjdk:master' into master

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Merge branch 'openjdk:master' into master

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Merge branch 'master' of https://github.com/mickleness/jdk

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Merge branch 'master' of https://github.com/mickleness/jdk

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Merge branch 'master' of https://github.com/mickleness/jdk

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8356320: adding resource leo.gif

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8356137: updating (c) year

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openjdk bot added the rfr Pull request is ready for review label May 7, 2025

openjdk bot added the client [email protected] label May 7, 2025

mickleness mentioned this pull request May 14, 2025

8356137: GifImageDecode can produce opaque image when disposal method changes #25044

Closed

3 tasks

mickleness added 5 commits May 14, 2025 19:11

GifComparison: adding common helper class for gif bugs

20839dc

8356320: change package to access GifComparison

a067ba6

GifComparison: code cleanup

91427f7

GifComparison: fixing error message

63ea01a

8356320: fixing copy & paste typo

178c006

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mickleness closed this May 15, 2025

mickleness added 2 commits May 14, 2025 23:07

Merge branch 'master' of https://github.com/mickleness/jdk

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Merge branch 'master' of https://github.com/mickleness/jdk

80944a2

This was referenced May 26, 2025

8351913: ToolkitImage renders some gifs wrong #24271

Open

8357034: GifImageDecoder can produce wrong transparent pixels #25264

Closed

mickleness reopened this May 26, 2025

mickleness marked this pull request as draft May 26, 2025 05:17

openjdk bot removed the rfr Pull request is ready for review label May 26, 2025

8356137: Adding copyright to GifComparison

55d22ba

mickleness added 6 commits June 1, 2025 03:03

8356137: trivial javadoc update

e03d7c2

8356137: Adding GifBuilder to dynamically create test file

7a5a692

This can be used by multiple gif tests in this directory. This is in response to: openjdk#25044 (review)

8356137: adding copyright

387b4b3

8356320: Use new GifBuilder and remove leo.gif

ad4dcac

This is an extension of work for this PR: openjdk#25044 (review)

Merge branch 'master' into JDK-8356320

35fedf0

openjdk bot added the merge-conflict Pull request has merge conflict with target branch label Jul 11, 2025

Merge branch 'master' into JDK-8356320

3deeb49

# Conflicts: # test/jdk/sun/awt/image/gif/GifBuilder.java # test/jdk/sun/awt/image/gif/GifComparison.java

openjdk bot removed the merge-conflict Pull request has merge conflict with target branch label Jul 11, 2025

mickleness marked this pull request as ready for review July 11, 2025 22:56

openjdk bot added the rfr Pull request is ready for review label Jul 11, 2025

jayathirthrao approved these changes Aug 4, 2025

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mickleness marked this pull request as draft August 4, 2025 16:59

openjdk bot removed the rfr Pull request is ready for review label Aug 4, 2025

mickleness closed this Nov 6, 2025

8356320: GifImageDecoder can produce wrong image when GCE changes transparent pixel index #25076

8356320: GifImageDecoder can produce wrong image when GCE changes transparent pixel index #25076

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