1640347 - Drop shadows render incorrectly briefly while pinch-zooming

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect, P3)

Description

[Connor Brewster [:cbrewster]]

Attachment: pinch-zoom-dropshadow-bug.mov

STR:

1. Enable WebRender
2. Enable apz.allow_zooming
3. Go to https://developer.mozilla.org/en-US/docs/Web/SVG/Element/feDropShadow
4. Pinch-zoom over the drop-shadow example
5. The drop shadow renders incorrectly but fixes itself after invalidation

Comment 1

[Timothy Nikkel (:tnikkel)]

It seems that to see the problem the drop shadow has to intersect the boundary of the viewport and the shadow decides that it's bounds are now limited by the viewport.

Comment 2

[Timothy Nikkel (:tnikkel)]

Seems to be a regression, 2020-01-01 is better, but not perfect.

Comment 3

[Kris Taeleman (:ktaeleman)]

@kats: can't reproduce, needs regression check

Comment 4

[Kartikaya Gupta (email:[e-mail])]

mozregression says this was fixed by https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=8ab5f308563d7e5ba91632d751895e8fc2079bd2&tochange=e2390cba7abf74b21fe9cfc20d8cfec2f1c0fcce. There's still some clipping/checkerboarding problems but that's tracked in other bugs.