[CSSRegions] RenderFlowThread::renderRegionForLine should use a faster search method

• Component: Layout and Rendering
• Status: RESOLVED FIXED

[Alexandru Chiculita]

The RenderRegion rects are always in order. There should be a faster way to search the region at a specified position.

[Radar WebKit Bug Importer]

<rdar://problem/10218165>

[Mihai Balan]

Created attachment 158840 [details]
A sample from a client, that might prove to be a good test-case for this. Addmitedly, the algorithm is (very) naive, but it shouldn't take 5 minutes to finish, nonetheless.

[Andrei Bucur]

Created attachment 196358 [details]
Patch

[Andrei Bucur]

Comment on attachment 196358 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=196358&action=review

> Source/WebCore/rendering/RenderFlowThread.cpp:968
> +    if (interval.data()->isRenderRegionSet())

Is it possible we'd want to return a region set that's not the last region? The old code seemed to have allowed it.

[Dave Hyatt]

Comment on attachment 196358 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=196358&action=review

Please handle

expandToEncompassFlowThreadContentsIfNeeded()

which hacks the flow thread portion rect. You'll want to make sure that interval gets correctly updated.

> Source/WebCore/rendering/RenderFlowThread.cpp:827
> +        m_regionIntervalTree.add(RegionIntervalTree::createInterval(regionRect.y(), regionRect.maxY(), region));

I think because of writing modes it would read better not to use y() and maxY() here. You could just use logicalHeight and logicalHeight + regionLogicalHeight, and I think that would read slightly better.

>> Source/WebCore/rendering/RenderFlowThread.cpp:968
>> +    if (interval.data()->isRenderRegionSet())
> 
> Is it possible we'd want to return a region set that's not the last region? The old code seemed to have allowed it.

Yes, it will be possible to have multiple region sets. Your code is going to be applicable to region sets.

[Andrei Bucur]

Created attachment 196363 [details]
Patch

[Dave Hyatt]

Comment on attachment 196363 [details]
Patch

r=me

[WebKit Review Bot]

Comment on attachment 196363 [details]
Patch

Clearing flags on attachment: 196363

Committed r147620: <http://trac.webkit.org/changeset/147620>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.