[Webkit-unassigned] [Bug 84306] [Qt][WK2] Fixed layers are shaking when zoom level is not 1.0 due to a rounding error.

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=84306





--- Comment #14 from Noam Rosenthal <noam.rosenthal at nokia.com>  2012-04-27 06:00:13 PST ---
(From update of attachment 139067)
View in context: https://bugs.webkit.org/attachment.cgi?id=139067&action=review

> Source/WebKit2/UIProcess/WebLayerTreeRenderer.cpp:111
> +    TransformationMatrix newMatrix = matrix;
> +    newMatrix.setM41(newMatrix.m41() + m_roundingAdjustment.width());
> +    newMatrix.setM42(newMatrix.m42() + m_roundingAdjustment.height());
> +

just use translate(m_roundingAdjustment)

> Source/WebKit2/UIProcess/API/qt/qquickwebview.cpp:793
> +        layerTreeHostProxy->layerTreeRenderer()->setRoundingAdjustment(FloatSize(accurateVisibleRect.x() - visibleRect.x() * scale, accurateVisibleRect.y() - visibleRect.y() * scale));

This will create a flicker in certain situations.
LayerTreeRenderer updates the rounding adjustment here, but only updates the scroll position in didChangeScrollPosition. Those two values need to go in sync, e.g. by sending the rounding adjustment together with the trajectory, or something to that effect.

-- 
Configure bugmail: https://bugs.webkit.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.