1396298 - webrender: transform:rotation causes element to be drawn over the chrome

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Pierre-Yves Gérardy]

Attachment: Screen Shot 2017-09-02 at 22.25.39.png

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:57.0) Gecko/20100101 Firefox/57.0
Build ID: 20170902100317

Steps to reproduce:

On Nightly (2017-09-02), with webrender.enabled = true (and default options otherwise)

Set `transform: rotation(45deg)` on a non-transparent element.

Example:

    <style> 
    div {
      background-color:red;
      transform: rotate(-45deg);
    }
    </style>
    <div>Hello</div>

live here:
https://flems.io/#0=N4IgZglgNgpgziAXAbVAOwIYFsZJAOgAsAXLKEAGhAGMB7NYmBvAHjmIE9YA+AHTQAmEAG4ACYP1GiARhmoBrAOYAnWgFdBAWjpRayxMpgCA3JNHFlGNHDB6siUauIZGACk0AWAKwCYigJSmaAC+-CwA9OxcMHxoLELC3AASMFC6EQncIMEU6Ni4iAQAVghUdAxMxHjZuSCYOHj41HClNPSMzIXZALrBQA


Actual results:

The element is drawn over some of the chrome (tab bar and hairline between the page and the URL bar).

Comment 1

[Pierre-Yves Gérardy]

Attachment: With layers-free and webrendest enabled

Comment 2

[Pierre-Yves Gérardy]

Attachment: With layers-free enabled (webrendest off)

Comment 3

[Pierre-Yves Gérardy]

Note that the problem doesn't show in the link above if `gfx.webrender.layers-free` is enabled.

http://j2c.py.gy/ is where I noticed the issue to begin with, and that page is still problematic in layers-free mode (though differently).

With `gfx.webrender.layers-free` and `webrendest` enabled, the ribbon appears in the glitchy shadows of logo. If you remove all the text-shadows using the dev tools (that other glitch was reported to github/webrender directly), it appears once again in the tab bar.

Comment 4

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

Probably same root cause as bug 1395731.

Comment 5

[Markus Stange [:mstange]]

I can't reproduce this, and it looks like this was never a problem with layers-free, which is the only available configuration now.

Comment 6

[Pierre-Yves Gérardy]

I can't reproduce it anymore either, but please note that layers-free was also affected, not with the original link but with http://j2c.py.gy/ (see comment #3 and associated screencap).

Comment 7

[Markus Stange [:mstange]]

Oh, I see. Well, nice to see that it seems to be fixed. :)
The j2c problem may have been fixed by bug 1405951.