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

[Jeremy Wood]

On Wed, 7 May 2025 02:55:12 GMT, Jeremy Wood <duke at openjdk.org> wrote:

> 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.
> 
> (I know this looks similar to https://github.com/openjdk/jdk/pull/25044 , but if you look at the data structure of the sample gifs: they are separate problems with separate solutions.)

Closing temporarily. As noted [here](https://github.com/openjdk/jdk/pull/25044#issuecomment-2881889090): this new test case is blocked. Once incident report 9078482 clears: I can make a PR for that new ticket. Once that ticket is merged: this test will pass.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/25076#issuecomment-2881892650