Bug 208971 – [GPU Process] GraphicsContextStateChange must accumulate fill and stroke fields as single properties

• Status: RESOLVED
• Resolution: FIXED
• Component: Canvas

[Said Abou-Hallawa]

The fill and stroke can be color, gradient or pattern. When setting the fill or the stroke of the GraphicsContextState to any of them, the other two are nullified. GraphicsContextStateChange should behave similarly when any of the fill or the stroke flags is true.

[Said Abou-Hallawa]

Created attachment 393331 [details]
test case

[Said Abou-Hallawa]

Repro steps:

1. Launch mini-browser
2. Enable Settings/Internal Features/Render Canvas in GPU Process
3. Open the attached test case

Result: the test case shows a red rectangle
Expected: the test case shows a green rectangle

[Said Abou-Hallawa]

The same bug happens when enabling Settings/Enable Display List Drawing.

[Said Abou-Hallawa]

Created attachment 393332 [details]
Patch

[Said Abou-Hallawa]

This fixes the following tests:

canvas/philip/tests/2d.pattern.modify.canvas2.html
canvas/philip/tests/2d.pattern.modify.image2.html

when using the following command:

run-webkit-tests --debug --no-retry  --internal-feature RenderCanvasInGPUProcessEnabled LayoutTests/canvas/philip/tests/2d.pattern.modify.canvas2.html LayoutTests/canvas/philip/tests/2d.pattern.modify.image2.html

[Simon Fraser (smfr)]

Comment on attachment 393332 [details]
Patch

Should there be a TestExpectations change?

[Said Abou-Hallawa]

(In reply to Simon Fraser (smfr) from comment #6)
> Comment on attachment 393332 [details]
> Patch
> 
> Should there be a TestExpectations change?

The two tests I mentioned above fail only when running 'run-webkit-tests --internal-feature RenderCanvasInGPUProcessEnabled'. The attached test case fails in the browser when enabling GPU reddening or DisplayList rendering. The patch fixes the following scenario:

    var pattern = ctx1.createPattern(canvas2, 'no-repeat');
    ctx1.fillStyle = pattern;
    ctx1.fillRect(0, 0, canvas1.width, canvas1.height);

    ctx1.fillStyle = 'red';
    ctx1.fillRect(0, 0, canvas1.width, canvas1.height);

    ctx1.fillStyle = pattern;
    ctx1.fillRect(0, 0, canvas1.width, canvas1.height);

The bug is in the last fillStyle. GraphicsContextStateChange::changesFromState() returns 0 because although the flag GraphicsContextState::FillPatternChange is set, the value of the property 'fillPattern' is the same in m_state and state. So no SetState item is created for the last fillRect.

[Said Abou-Hallawa]

Created attachment 393341 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 393341 [details]
Patch

Clearing flags on attachment: 393341

Committed r258317: <https://trac.webkit.org/changeset/258317>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Radar WebKit Bug Importer]

<rdar://problem/60360906>