1818820 - Canvas 2D with Copy + Rotate(0) +Clip fails on Window 10

Status: VERIFIED FIXED

(Core :: Graphics: Canvas2D, defect)

Description

[raffy]

Attachment: Examples.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/110.0

Steps to reproduce:

function test(rot) {
let canvas = document.createElement('canvas');
canvas.style.border = '1px solid #000';
canvas.width = canvas.height = 200;
let ctx = canvas.getContext('2d');
ctx.globalCompositeOperation = 'copy';
ctx.translate(100, 100);
ctx.rotate(rot);
ctx.rect(-50, -50, 100, 100);
ctx.clip();
ctx.fillStyle = '#f00';
ctx.resetTransform();
ctx.fillRect(0, 0, canvas.width, canvas.height);
return canvas;
}

// works correctly
test(0.0001)
test(0.2)

// bugged
test(0)
test(Math.PI/2)
test(Math.PI)

Actual results:

When using composition "copy" with rotation at right angles, the clip region is ignored.

Expected results:

The clip region should be expected in all cases.

Comment 1

[Timothy Nikkel (:tnikkel)]

Attachment: cas.html

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1804952

:jrmuizel, since you are the author of the regressor, bug 1804952, could you take a look? Also, could you set the severity field?

For more information, please visit auto_nag documentation.

Comment 3

[Jeff Muizelaar [:jrmuizel]]

I think this is exposing an existing bug in the D2D backend.

Comment 4

[Jeff Muizelaar [:jrmuizel]]

I think the bug may have been caused by https://hg.mozilla.org/mozilla-central/rev/538d248fa252

Comment 5

[Jeff Muizelaar [:jrmuizel]]

Attachment: Bug 1818820. Fix drawing of some blend modes with non-complex clips.

This ensures that we have our clips pushed when we expect them to.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b7b8c57a5cba
Fix drawing of some blend modes with non-complex clips. r=bas

Comment 7

[Jeff Muizelaar [:jrmuizel]]

Comment on attachment 9320840 [details]
Bug 1818820. Fix drawing of some blend modes with non-complex clips.

Beta/Release Uplift Approval Request

• User impact if declined: Sometimes we ignore the clip in canvas
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: No
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): The common paths in canvas are quite well tested so if this introduces a problem it's likely to be rare.
• String changes made/needed:
• Is Android affected?: No

Comment 8

[Marian-Vasile Laza]

https://hg.mozilla.org/mozilla-central/rev/b7b8c57a5cba

Comment 10

[Donal Meehan [:dmeehan]]

Comment on attachment 9320840 [details]
Bug 1818820. Fix drawing of some blend modes with non-complex clips.

Approved for 111.0 RC1

Comment 11

[Donal Meehan [:dmeehan]]

https://hg.mozilla.org/releases/mozilla-beta/rev/4a97110c5bab

Comment 12

[raffy]

Impressive work Mozilla team. Thanks for the quick fix!

I apologize for the poorly formatted report and lack of one-click demo. It was my first bug report and I didn't know I could use markdown or provide an inline attachment.

Comment 13

[Monica Chiorean]

Reproduced the issue on Win10x64 using 110.0a1(20230105213109).
Verified as fixed on Win10x64/Ubuntu20.04/Mac10.13 using 112.0a1(20230306094520) and 111.0(20230306162820).