REGRESSION (r164449): Subpixel rendering: http://www.apple.com/iphone-6/ "Faster wireless." image displays vertical black line on 1x displays at specific window width.

• Component: Layout and Rendering
• Status: RESOLVED FIXED

[zalan]

1. Launch Safari on a 1x display
2. Navigate to http://www.apple.com/iphone-6/
3. Scroll down to "Faster wireless." image and adjust window width between 1,115 and 1,295 pixels

[zalan]

rdar://problem/18307094

[zalan]

Created attachment 252560 [details]
Patch

[Build Bot]

Comment on attachment 252560 [details]
Patch

Attachment 252560 [details] did not pass mac-wk2-ews (mac-wk2):
Output: http://webkit-queues.appspot.com/results/5888337206312960

New failing tests:
compositing/layer-creation/overlap-animation-container.html

[Build Bot]

Created attachment 252561 [details]
Archive of layout-test-results from ews105 for mac-mavericks-wk2

The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews.
Bot: ews105  Port: mac-mavericks-wk2  Platform: Mac OS X 10.9.5

[Simon Fraser (smfr)]

Comment on attachment 252560 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=252560&action=review

> Source/WebCore/rendering/RenderLayerBacking.cpp:728
> +        ancestorCompositingBounds = LayoutRect(encloseRectToDevicePixels(compAncestor->backing()->compositedBounds(), deviceScaleFactor));

Should we just store the encloseRectToDevicePixels rect on the backing?

Also, doesn't this also break our rule that you can only do enclosing computations on things that are in absolute coordinates?

> LayoutTests/ChangeLog:16
> +        * compositing/ancestor-compositing-layer-is-on-subpixel-position-expected.html: Added.
> +        * compositing/ancestor-compositing-layer-is-on-subpixel-position.html: Added.

Do ref tests actually pick up the difference? I would have thought a layer tree dump would be more reliable.

[Build Bot]

Comment on attachment 252560 [details]
Patch

Attachment 252560 [details] did not pass mac-ews (mac):
Output: http://webkit-queues.appspot.com/results/4598034541314048

New failing tests:
compositing/layer-creation/overlap-animation-container.html

[Build Bot]

Created attachment 252563 [details]
Archive of layout-test-results from ews101 for mac-mavericks

The attached test failures were seen while running run-webkit-tests on the mac-ews.
Bot: ews101  Port: mac-mavericks  Platform: Mac OS X 10.9.5

[zalan]

Created attachment 252564 [details]
Patch

[zalan]

(In reply to comment #7)
> Created attachment 252563 [details]
> Archive of layout-test-results from ews101 for mac-mavericks
> 
> The attached test failures were seen while running run-webkit-tests on the
> mac-ews.
> Bot: ews101  Port: mac-mavericks  Platform: Mac OS X 10.9.5
This is a progression.

[zalan]

Created attachment 252604 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 252604 [details]
Patch

Clearing flags on attachment: 252604

Committed r183950: <http://trac.webkit.org/changeset/183950>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.