[New Multicolumn] Implement support for compositing

• Component: Layout and Rendering
• Status: RESOLVED FIXED

[Dave Hyatt]

All of the compositing tests that involve pagination mode on the RenderView just fail completely. They don't dump any layer trees.

[Dave Hyatt]

Created attachment 230410 [details]
Patch

[Simon Fraser (smfr)]

Comment on attachment 230410 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=230410&action=review

> Source/WebCore/rendering/RenderLayer.cpp:2065
> +                    location.moveBy(region->topLeftLocation() + -parentLayer->renderBox()->topLeftLocation());

+ - -> -?

> Source/WebCore/rendering/RenderMultiColumnSet.cpp:826
> +    LayoutUnit blockOffset = initialBlockOffset + (isHorizontalWritingMode() ? -flowThreadPortion.y() : -flowThreadPortion.x());

Change the plus with two minuses into a minus?

> LayoutTests/ChangeLog:10
> +        * compositing/columns/composited-columns-vertical-rl.html:

I don't think you meant to change this.

[Dave Hyatt]

Fixed in r167965.

[Alexey Proskuryakov]

This change broke fast/multicol/mixed-positioning-stacking-order.html on WebKit2 bots:

http://build.webkit.org/results/Apple%20Mavericks%20Release%20WK2%20(Tests)/r167977%20(5329)/fast/multicol/mixed-positioning-stacking-order-diffs.html

[Dave Hyatt]

(In reply to comment #4)
> This change broke fast/multicol/mixed-positioning-stacking-order.html on WebKit2 bots:
> 
> http://build.webkit.org/results/Apple%20Mavericks%20Release%20WK2%20(Tests)/r167977%20(5329)/fast/multicol/mixed-positioning-stacking-order-diffs.html

That's a progression, but I don't like how the test is rendering, so will probably try to find a way to keep compositing from happening. Let me come up with a tweak.