[webkit-reviews] review denied: [Bug 24571] Element is visible even if backface-visibility is 'hidden' and the back is facing towards the viewer. : [Attachment 28575] Patch to enable backface visibility property to have effect

[bugzilla-daemon at webkit.org]

Simon Fraser (smfr) <simon.fraser at apple.com> has denied 's request for review:
Bug 24571: Element is visible even if backface-visibility is 'hidden' and the
back is facing towards the viewer.
https://bugs.webkit.org/show_bug.cgi?id=24571

Attachment 28575: Patch to enable backface visibility property to have effect
https://bugs.webkit.org/attachment.cgi?id=28575&action=review

------- Additional Comments from Simon Fraser (smfr) <simon.fraser at apple.com>
> Index: WebCore/rendering/RenderLayer.cpp
> ===================================================================
> --- WebCore/rendering/RenderLayer.cpp (revision 41663)
> +++ WebCore/rendering/RenderLayer.cpp (working copy)
> @@ -1955,6 +1955,12 @@ RenderLayer::paintLayer(RenderLayer* roo
>	   TransformationMatrix transform;
>	   transform.translate(x, y);
>	   transform = *m_transform * transform;
> +
> +	   // Don't paint anything if backface-visibility is 'hidden' and the
back is facing towards the viewer.
> +	   if (renderer()->style()->backfaceVisibility() ==
BackfaceVisibilityHidden) {
> +	       if (transform.inverse().m33() < 0)
> +	       return;
> +	   }

This is wrong; backface-visibility has to take into account the transform to
the root, not just the parent layer. It really needs to be implemented by the
GraphicsLayer machinery.