[webkit-reviews] review granted: [Bug 195371] Compositing layer that renders two positioned elements should not hit test : [Attachment 364262] patch

[bugzilla-daemon at webkit.org]

Simon Fraser (smfr) <simon.fraser at apple.com> has granted Antti Koivisto
<koivisto at iki.fi>'s request for review:
Bug 195371: Compositing layer that renders two positioned elements should not
hit test
https://bugs.webkit.org/show_bug.cgi?id=195371

Attachment 364262: patch

https://bugs.webkit.org/attachment.cgi?id=364262&action=review




--- Comment #13 from Simon Fraser (smfr) <simon.fraser at apple.com> ---
Comment on attachment 364262
  --> https://bugs.webkit.org/attachment.cgi?id=364262
patch

View in context: https://bugs.webkit.org/attachment.cgi?id=364262&action=review

> Source/WebCore/rendering/RenderLayerBacking.cpp:2587
> +    if (eventRegion->contains(roundedIntRect(compositedBounds())))
> +	   eventRegion = nullptr;

When does this happen? Is this the case for a simple layer which is fully
hit-testable?

>
Source/WebKit/WebProcess/WebPage/RemoteLayerTree/PlatformCALayerRemote.cpp:884
> +    m_properties.eventRegion =
std::make_unique<WebCore::Region>(*eventRegion);

Is it worth comparing regions? Not doing so will trigger region encoding on
every paint, right?