Bug 129859 – Subpixel rendering: Transform origin is miscalculated when RenderLayer's offsetfromRenderer has device pixel fraction value.

• Component: Layout and Rendering
• Status: RESOLVED FIXED

[zalan]

Miscalculated transform origin produces off by one rendering errors for transforms like rotate.

[zalan]

This patch requires to be able to test hidpi compositing layers. bug 129961

[zalan]

Created attachment 226244 [details]
Patch

[Simon Fraser (smfr)]

Comment on attachment 226244 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=226244&action=review

> Source/WebCore/rendering/RenderLayerBacking.cpp:845
> +        LayoutRect layerBounds(LayoutPoint(roundedForPainting(offsetFromParent, deviceScaleFactor)), borderBox.size());

It's a bit odd that the origin is device-pixel snapped, but the size is not. Does this work for large boxes where a percentage transform-origin could be visibly affected by the exact size?

[zalan]

(In reply to comment #3)
> (From update of attachment 226244 [details])
> View in context: https://bugs.webkit.org/attachment.cgi?id=226244&action=review
> 
> > Source/WebCore/rendering/RenderLayerBacking.cpp:845
> > +        LayoutRect layerBounds(LayoutPoint(roundedForPainting(offsetFromParent, deviceScaleFactor)), borderBox.size());
> 
> It's a bit odd that the origin is device-pixel snapped, but the size is not. Does this work for large boxes where a percentage transform-origin could be visibly affected by the exact size?

Good catch. It is most likely incorrect.

[zalan]

Created attachment 226262 [details]
Patch

[zalan]

Comment on attachment 226262 [details]
Patch

EWSing

[Build Bot]

Comment on attachment 226262 [details]
Patch

Attachment 226262 [details] did not pass mac-wk2-ews (mac-wk2):
Output: http://webkit-queues.appspot.com/results/6043000496979968

New failing tests:
compositing/columns/composited-columns.html
compositing/repaint/resize-repaint.html
compositing/visibility/visibility-image-layers-dynamic.html
compositing/repaint/invalidations-on-composited-layers.html
compositing/geometry/limit-layer-bounds-opacity-transition.html

[Build Bot]

Created attachment 226263 [details]
Archive of layout-test-results from webkit-ews-10 for mac-mountainlion-wk2

The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews.
Bot: webkit-ews-10  Port: mac-mountainlion-wk2  Platform: Mac OS X 10.8.5

[Build Bot]

Comment on attachment 226262 [details]
Patch

Attachment 226262 [details] did not pass mac-ews (mac):
Output: http://webkit-queues.appspot.com/results/4645108901216256

New failing tests:
compositing/columns/composited-columns.html
compositing/repaint/resize-repaint.html
compositing/visibility/visibility-image-layers-dynamic.html
compositing/repaint/invalidations-on-composited-layers.html
compositing/geometry/limit-layer-bounds-opacity-transition.html

[Build Bot]

Created attachment 226264 [details]
Archive of layout-test-results from webkit-ews-03 for mac-mountainlion

The attached test failures were seen while running run-webkit-tests on the mac-ews.
Bot: webkit-ews-03  Port: mac-mountainlion  Platform: Mac OS X 10.8.5

[Build Bot]

Comment on attachment 226262 [details]
Patch

Attachment 226262 [details] did not pass mac-wk2-ews (mac-wk2):
Output: http://webkit-queues.appspot.com/results/6612167415562240

New failing tests:
compositing/columns/composited-columns.html
compositing/repaint/resize-repaint.html
compositing/visibility/visibility-image-layers-dynamic.html
compositing/repaint/invalidations-on-composited-layers.html
compositing/geometry/limit-layer-bounds-opacity-transition.html

[Build Bot]

Created attachment 226265 [details]
Archive of layout-test-results from webkit-ews-11 for mac-mountainlion-wk2

The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews.
Bot: webkit-ews-11  Port: mac-mountainlion-wk2  Platform: Mac OS X 10.8.5

[Build Bot]

Comment on attachment 226262 [details]
Patch

Attachment 226262 [details] did not pass mac-ews (mac):
Output: http://webkit-queues.appspot.com/results/6541343404851200

New failing tests:
compositing/columns/composited-columns.html
compositing/repaint/resize-repaint.html
compositing/visibility/visibility-image-layers-dynamic.html
compositing/repaint/invalidations-on-composited-layers.html
compositing/geometry/limit-layer-bounds-opacity-transition.html

[Build Bot]

Created attachment 226271 [details]
Archive of layout-test-results from webkit-ews-07 for mac-mountainlion

The attached test failures were seen while running run-webkit-tests on the mac-ews.
Bot: webkit-ews-07  Port: mac-mountainlion  Platform: Mac OS X 10.8.5

[zalan]

Created attachment 226469 [details]
Patch

[Simon Fraser (smfr)]

Comment on attachment 226469 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=226469&action=review

> LayoutTests/platform/mac/compositing/visibility/visibility-image-layers-dynamic-expected.txt:114
> +          (anchor 0.50 0.50)

Are these just slightly different from 0.5? Maybe we need to print more precision.

> Source/WebCore/rendering/RenderLayerBacking.cpp:848
> +        FloatPoint3D anchor(enclosingRelativeCompositingBounds.width() != 0.0f ? ((layerOffset.x() - enclosingRelativeCompositingBounds.x()) + transformOrigin.x())
> +            / enclosingRelativeCompositingBounds.width() : 0.5f, enclosingRelativeCompositingBounds.height() != 0.0f ? ((layerOffset.y() - enclosingRelativeCompositingBounds.y())

0.0f -> 0, 0.5f -> 0.5

[zalan]

Created attachment 227150 [details]
Patch

[zalan]

Comment on attachment 227150 [details]
Patch

EWS testing.

[zalan]

(In reply to comment #16)
> (From update of attachment 226469 [details])
> View in context: https://bugs.webkit.org/attachment.cgi?id=226469&action=review
> 
> > LayoutTests/platform/mac/compositing/visibility/visibility-image-layers-dynamic-expected.txt:114
> > +          (anchor 0.50 0.50)
> 
> Are these just slightly different from 0.5? Maybe we need to print more precision.
bug 130442

> 
> > Source/WebCore/rendering/RenderLayerBacking.cpp:848
> > +        FloatPoint3D anchor(enclosingRelativeCompositingBounds.width() != 0.0f ? ((layerOffset.x() - enclosingRelativeCompositingBounds.x()) + transformOrigin.x())
> > +            / enclosingRelativeCompositingBounds.width() : 0.5f, enclosingRelativeCompositingBounds.height() != 0.0f ? ((layerOffset.y() - enclosingRelativeCompositingBounds.y())
> 
> 0.0f -> 0, 0.5f -> 0.5
done.

[WebKit Commit Bot]

Comment on attachment 227150 [details]
Patch

Clearing flags on attachment: 227150

Committed r165892: <http://trac.webkit.org/changeset/165892>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.