1724990 - box shadow is broken in a specific situation

Status: NEW

(Core :: Graphics: WebRender, defect)

Description

[Alireza Shabani]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:90.0) Gecko/20100101 Firefox/90.0

Steps to reproduce:

in this link https://jsfiddle.net/jxg8hvcn/ I made a situation that if there are Arabic and English letters in that hyperlink, the box-shadow looks broken. but if there are Arabic letters only or English letters only, box-shadow looks fine.

Actual results:

this is an image of how it looks in Firefox:
https://i.ibb.co/6y70Zbw/Screenshot-from-2021-08-10-22-53-20.png

Expected results:

and here is how it should look (from chrome):
https://i.ibb.co/RHTxPWh/Screenshot-from-2021-08-10-22-55-54.png

Comment 1

[Pablo]

I was able to reproduce this using windows 10 64bit, MacOs 11, and ubuntu 20 using:
Firefox Release 91.0
Firefox Beta 92.0b2
Firefox Nigtly 93.0a1

Comment 2

[Alice0775 White]

Disabling WebRender solves the problem in Nightly 93.0a1 on Windows 10.

Comment 3

[Darkspirit]

Thanks for the report!
It's broken right from the beginning.
MOZ_DISABLE_CONTENT_SANDBOX=1 mozregression --good 2017-03-11 --bad 2017-04-11 --pref gfx.webrender.all:true layers.acceleration.force-enabled:true gfx.webrender.enabled:true gfx.webrendest.enabled:true gfx.webrender.layers-free:true gfx.webrender.blob-images:true image.mem.shared:true layout.display-list.retain:false -a https://jsfiddle.net/jxg8hvcn/

3:27.05 INFO: Last good revision: b043233ec04f06768d59dcdfb9e928142280f3cc (2017-04-05)
3:27.05 INFO: First bad revision: 3c68d659c2b715f811708f043a1e7169d77be2ba (2017-04-06)
3:27.05 INFO: Pushlog:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=b043233ec04f06768d59dcdfb9e928142280f3cc&tochange=3c68d659c2b715f811708f043a1e7169d77be2ba

likely

6b6847ceb7c9137107eb43ca4b75bb66736e01b3 Mason Chang — Bug 1347727 - Enable outer box shadows by default in WR. r=rhunt

because this bug can be reproduced with "last good" when setting layers.advanced.boxshadow-outer-layers to 1:

MOZ_DISABLE_CONTENT_SANDBOX=1 mozregression --launch 2017-04-05 --pref gfx.webrender.all:true layers.acceleration.force-enabled:true gfx.webrender.enabled:true gfx.webrendest.enabled:true gfx.webrender.layers-free:true gfx.webrender.blob-images:true image.mem.shared:true layout.display-list.retain:false layers.advanced.boxshadow-outer-layers:1 -a https://jsfiddle.net/jxg8hvcn/

Comment 4

[Marco Castelluccio [:marco]]

Set release status flags based on info from the regressing bug 1347727

Comment 5

[Jim Blandy :jimb]

I can reproduce this on a recent nightly on Fedora, using the jsfiddle link.

Comment 6

[Glenn Watson [:gw]]

Hard to know what's going on here without some further investigations and debugging. The first thing I'd probably check are the bounding boxes of the box-shadow and text primitives that get passed to WR for the text in the broken Arabic letter case. I wonder if we end up with some kind of invalid or incorrect bounds here.

Comment 7

[Mayank Bansal]

Attachment: Reporters_Standalone_testcase.html

Can still repro this bug on the latest Nightly.