Bug 68120 – REGRESSION (Safari 5.0.5-5.1): Images briefly appear pixelated after a resize

• Component: Images
• Status: NEW

Redrawing of images when changing their size via Javascript is poorer in builds 534+ than in build 533 on MacOS X and iOS. The images are visibly pixelated when first loaded, then smooth about a second later. This appears to occur however the image is resized; I can repro by manipulating the images or divs surrounding them. 


Repros in:
* Safari Mobile on iOS5b7
* MacOS X on chrome 13
* MacOS X Chrome (Canary) 16.0.881.0
* MacOS X Chrome 13.0.782.220
* MacOS X Safari 5.1
* MacOS X WebKit nightly r95080. 

Does not repro in:
* Safari Mobile on iOS 4.3 
* MacOS X Chrome 5.0.342.9 (latest version of Chrome I could find with WebKit 533) 
* Windows equivalents of Chrome and Safari.



STEPS TO REPRODUCE

1. View one of the attached test pages in an affected browser on MacOS X.

2. Click the Toggle button to resize.

Expected: image resizes smoothly.
Actual: image is jagged, then smoothed a second later.

Created attachment 107420 [details]
Examples

[Alexey Proskuryakov]

WebKit intentionally lowers interpolation quality during animation. But that was implemented long ago (http://trac.webkit.org/changeset/34210), and doesn't explain the regression.

Not sure when this broke, maybe in <http://trac.webkit.org/changeset/61341> or in <http://trac.webkit.org/changeset/61710>? CC'ing some people who worked on this in the past.

[Magnesus]

This is broken in QtWebKit too since 4.8.0 version. (since QtWebKit 2.2.1)