Bug 119462 – Force elements with perspective or preserve-3d to disallow direct composited backgrounds

• Component: Layout and Rendering
• Status: RESOLVED FIXED

[Dean Jackson]

As a stop-gap measure to address Bug 119461, make sure elements that have a perspective or preserve-3d don't allow directly composited backgrounds.

[Dean Jackson]

Created attachment 208053 [details]
Patch

[Dean Jackson]

<rdar://problem/14607548>

[Simon Fraser (smfr)]

Comment on attachment 208053 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=208053&action=review

> Source/WebCore/rendering/RenderLayerBacking.cpp:1518
> +    if (hasPerspectiveOrPreserves3D(renderer->style()))
> +        return false;

I think we need to do the same thing for simple image layers; they should show the same bug.

[Dean Jackson]

(In reply to comment #3)
> (From update of attachment 208053 [details])
> View in context: https://bugs.webkit.org/attachment.cgi?id=208053&action=review
> 
> > Source/WebCore/rendering/RenderLayerBacking.cpp:1518
> > +    if (hasPerspectiveOrPreserves3D(renderer->style()))
> > +        return false;
> 
> I think we need to do the same thing for simple image layers; they should show the same bug.

Simple image layers can't have children, so nothing to intersect with.

[Simon Fraser (smfr)]

Comment on attachment 208053 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=208053&action=review

>>> Source/WebCore/rendering/RenderLayerBacking.cpp:1518
>>> +        return false;
>> 
>> I think we need to do the same thing for simple image layers; they should show the same bug.
> 
> Simple image layers can't have children, so nothing to intersect with.

True dat!

> LayoutTests/compositing/background-color/no-composited-background-color-when-perspective-expected.html:16
> +    background-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAMAAAC6sdbXAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAAZQTFRFAAAA////pdmf3QAAAA5JREFUeNpiYMAHAAIMAAAeAAHMILKLAAAAAElFTkSuQmCC");

This might fall into a future background-image optimization. Maybe better to use border: 5px solid black and box-sizing: foo.

[Dean Jackson]

Comment on attachment 208053 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=208053&action=review

>> LayoutTests/compositing/background-color/no-composited-background-color-when-perspective-expected.html:16
>> +    background-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAMAAAC6sdbXAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAAZQTFRFAAAA////pdmf3QAAAA5JREFUeNpiYMAHAAIMAAAeAAHMILKLAAAAAElFTkSuQmCC");
> 
> This might fall into a future background-image optimization. Maybe better to use border: 5px solid black and box-sizing: foo.

Yeah, but unfortunately that slightly changes either the perspective origin or the transform origin. I'm not sure why this is - sounds like a bug!

[Dean Jackson]

Committed r153681: <http://trac.webkit.org/changeset/153681>