Bug 203613 – The image is flashing if falls out and has an animation transform: rotate

• Component: Compositing
• Status: RESOLVED FIXED

[Roman Kosov]

Created attachment 382324 [details]
image with animation transform: rotate = flashing

The image is flashing if falls out and has an animation transform: rotate.

Preview: https://codepen.io/romankosov/full/GRRMPJJ
Code: https://codepen.io/romankosov/pen/GRRMPJJ

MacOS X: 10.15.1 Beta (19B86a)
Safri: Version 13.0.3 (15608.3.10.1.4)

[Said Abou-Hallawa]

The flashing happens only when resizing the window or scrolling the page horizontally such that the image is partially visible. And it is not because of image decoding.

[Radar WebKit Bug Importer]

<rdar://problem/56748028>

[Simon Fraser (smfr)]

This is about backing store detachment.

[Simon Fraser (smfr)]

Created attachment 383525 [details]
Reduced test case

[Simon Fraser (smfr)]

This code is wrong:
    if (auto extent = animationExtent()) {
        // Adjust the animation extent to match the current animation position.
        bounds = rects.animatingTransform.inverse().valueOr(TransformationMatrix()).mapRect(*extent);
    }

[Simon Fraser (smfr)]

Antti added this code in r218735

[Simon Fraser (smfr)]

I don't think we need to map "extent" through the inverses of the current transform, because "extent" was computed as the union of all the possible bounds that result from the animation.

[Simon Fraser (smfr)]

Created attachment 383574 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 383574 [details]
Patch

Clearing flags on attachment: 383574

Committed r252486: <https://trac.webkit.org/changeset/252486>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.