Bug 197251 – REGRESSION(r244372): [GTK][WPE] fast/images/icon-decoding.html and others are failing

• Component: WebKitGTK
• Status: RESOLVED FIXED

[Alicia Boya García]

The following tests are failing on GTK since r244372:r244375

fast/images/icon-decoding.html
fast/images/reset-image-animation.html
fast/images/slower-animation-than-decoding-image.html
fast/images/slower-decoding-than-animation-image.html

Image failures:

css3/shapes/shape-outside/shape-image/shape-image-025.html
fast/images/animated-image-loop-count.html
imported/w3c/web-platform-tests/css/css-shapes/shape-outside/shape-image/shape-image-025.html

[Michael Catanzaro]

That's going to be "ScalableImageDecoder: don't forcefully decode image data when querying frame completeness, duration" again

[Miguel Gomez]

Several tests are failing on the WPE bot as well, and as Michael comments, the culprit seems to be r244372 "ScalableImageDecoder: don't forcefully decode image data when querying frame completeness, duration"

fast/images/icon-decoding.html [ Failure ]
fast/images/reset-image-animation.html [ Failure ]
fast/images/slower-animation-than-decoding-image.html [ Failure ]
fast/images/slower-decoding-than-animation-image.html [ Failure ]
fast/images/animated-image-loop-count.html [ ImageOnlyFailure ]
fast/images/animated-webp.html [ ImageOnlyFailure ]

[Miguel Gomez]

I've been giving a look to this. There are 3 different issues.

First: fast/images/icon-decoding.html just needs new baseline

Second: https://github.com/WebKit/webkit/blob/1240cfe9a01ee4469fdaaacdf3056c4401b01b24/Source/WebCore/platform/image-decoders/ScalableImageDecoder.cpp#L205

is causing that even non complete frames have a duration of 100ms. We should return 0_s if !frame.isComplete(), and avoid the 11ms change. This fixes these tests:

fast/images/reset-image-animation.html
fast/images/slower-animation-than-decoding-image.html
fast/images/slower-decoding-than-animation-image.html
fast/images/animated-image-loop-count.html

Then
css3/shapes/shape-outside/shape-image/shape-image-025.html
imported/w3c/web-platform-tests/css/css-shapes/shape-outside/shape-image/shape-image-025.html

are a bit trickier. They are testing that when using shape-outside on an animated image, the shape must be generated from the first frame of the animation. I've been debugging the code and I can see how the shape is being generated for each frame of the animation (both before and after the regression), and I think that these were passing before just by chance.
The thing is that just decoding the first frame would be enough for the shape image, but nothing indicates that and the complete animation is decoded. With each decoded frame, RenderBox::imageChanged() ends up being invoked and that causes the shape to be marked as dirty, so the next time we want to use it we'll generate it again from the new frame. I think we should somehow indicate that we don't want to decode the full animation when drawing the first frame (BitmapImage::draw()), but I need to check how the Apple ports deal with this, as it's not failing there.

[Miguel Gomez]

I'm going to split this bug into 2, cause there are 2 issues here, one in ScalableDecoder and another one that seems to be in the multiplatform code handling the shape-outside property.

I leave this bug for the ScalableImageDecoder problem and I've created https://bugs.webkit.org/show_bug.cgi?id=203240 to handle the (possible) multiplatform issue.

[Miguel Gomez]

*** Bug 197501 has been marked as a duplicate of this bug. ***

[Miguel Gomez]

Created attachment 381541 [details]
Patch

[Adrian Perez]

Comment on attachment 381541 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=381541&action=review

There is a small typo in the ChangeLog; please fix it before landing.

> Source/WebCore/ChangeLog:10
> +        Covered by existent tests.

s/existent/existing/

[Miguel Gomez]

Created attachment 381543 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 381543 [details]
Patch

Clearing flags on attachment: 381543

Committed r251431: <https://trac.webkit.org/changeset/251431>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.