Bug 130015 – [CSS Regions] Hit-testing is not working properly inside scrollable regions

• Status: RESOLVED
• Resolution: FIXED
• Component: CSS

[Radu Stavila]

Hit-testing on elements inside scrollable regions does not take the region's scroll offset into consideration.

[Radu Stavila]

Created attachment 226313 [details]
Patch

[Darin Adler]

Comment on attachment 226313 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=226313&action=review

> Source/WebCore/rendering/RenderLayer.cpp:6879
> +    IntSize scrolledContentOffset = region->fragmentContainer().hasOverflowClip() ? region->fragmentContainer().scrolledContentOffset() : IntSize();

Why would we want to skip the call to scrolledContentOffset is the container does not handle overflow? Wouldn’t the container correctly return 0,0 in that case? This seems mysterious enough that you might want to write a comment.

[Radu Stavila]

Comment on attachment 226313 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=226313&action=review

>> Source/WebCore/rendering/RenderLayer.cpp:6879
>> +    IntSize scrolledContentOffset = region->fragmentContainer().hasOverflowClip() ? region->fragmentContainer().scrolledContentOffset() : IntSize();
> 
> Why would we want to skip the call to scrolledContentOffset is the container does not handle overflow? Wouldn’t the container correctly return 0,0 in that case? This seems mysterious enough that you might want to write a comment.

The first line of the RenderBox::scrolledContentOffset() method is ASSERT(hasOverflowClip());

[Antti Koivisto]

Comment on attachment 226313 [details]
Patch

r=me with the informative comment Darin asked for.

[Radu Stavila]

After discussing with Antti on IRC, we decided to not add the comment, since throughout the code, every time the scrolledContentOffset is used, it's preceeded by the hasOverflowClip check. I will submit an issue to move the check inside the scrolledContentOffset method itself.

[WebKit Commit Bot]

Comment on attachment 226313 [details]
Patch

Clearing flags on attachment: 226313

Committed r165388: <http://trac.webkit.org/changeset/165388>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.