[webkit-reviews] review granted: [Bug 196508] Async overflow scroll on iOS paints slowly if it has a negative z-index child : [Attachment 371119] Patch

[bugzilla-daemon at webkit.org]

Dean Jackson <dino at apple.com> has granted Simon Fraser (smfr)
<simon.fraser at apple.com>'s request for review:
Bug 196508: Async overflow scroll on iOS paints slowly if it has a negative
z-index child
https://bugs.webkit.org/show_bug.cgi?id=196508

Attachment 371119: Patch

https://bugs.webkit.org/attachment.cgi?id=371119&action=review




--- Comment #7 from Dean Jackson <dino at apple.com> ---
Comment on attachment 371119
  --> https://bugs.webkit.org/attachment.cgi?id=371119
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=371119&action=review

> Source/WebCore/ChangeLog:13
> +	   Fix by updating the fore- and background-layers last (nothing elese
has dependencies

typo: else

> Source/WebCore/rendering/RenderLayerBacking.cpp:1274
> +	   if (m_scrolledContentsLayer) {
> +	       foregroundSize = m_scrolledContentsLayer->size();
> +	       foregroundOffset = m_scrolledContentsLayer->offsetFromRenderer()
- toLayoutSize(m_scrolledContentsLayer->scrollOffset());
> +	       needsDisplayOnOffsetChange = GraphicsLayer::DontSetNeedsDisplay;
> +	   } else {
> +	       foregroundSize = primaryGraphicsLayerRect.size();
> +	       foregroundOffset = m_graphicsLayer->offsetFromRenderer();
> +	   }
> +
> +	   if (hasClippingLayer()) {
> +	       // If we have a clipping layer (which clips descendants), then
the foreground layer is a child of it,
> +	       // so that it gets correctly sorted with children. In that case,
position relative to the clipping layer.
> +	       foregroundSize = FloatSize(clippingBox.size());
> +	       foregroundOffset = toFloatSize(clippingBox.location());
> +	   }

This can be

if (hasClippingLayer()) {


} else {
 if (m_scrolledContentsLayer) {

 } else {

 }
}

Although I guess you still need the needsDisplayOnOffsetChange... :(