somewhere the rendering of pixel level graphics is broken, banding is readily evident in the attached images and is limited to Safari-webkit and Chromium, not able to be reproduced using Opera nor Mozilla I have attached a testcase that uses lerp to interpolate colour values, and produce gradients across 2 dimensions, rather than a simple linear gradient. I have not been able to identify precise reasons, however in a broad range of situations, using a variety of methods, banding is always present.
Created attachment 74946 [details] screengrab 1
Created attachment 74947 [details] screengrab 2
Created attachment 74948 [details] screengrab 3
Created attachment 74949 [details] screengrab 4 showing opacity
Created attachment 74950 [details] script to produce banding effect (ie not by design)
apologies, need to qualify testcase better.
Created attachment 74951 [details] uses percentage width and height
it is not that Opera and Mozilla cannot be made to produce banding, rather it is far more difficult. In the particular use-case, not given as large file, I have not yet found a way to reduce banding, which is not present at all in other browsers
Created attachment 74957 [details] Firefox screenshot FWIW, I'm seeing the same in Firefox 3.6 on Mac.
Created attachment 74959 [details] shows relative merits
ap, please compare safarti, mozilla and opera in similar size windows etc. I have attached an example, not contrived,just as quickly as possible. full screen height then shifted left to overlay. there is a considerable difference. could raise issue with working group? obviously no client should interpolate white lines, where data has been provided. on the other hand there is a 'speed' issue, as interpolation takes cycles.
(In reply to comment #11) > ap, > > please compare safarti, mozilla and opera in similar size windows etc. > > I have attached an example, not contrived,just as quickly as possible. > > full screen height then shifted left to overlay. > > there is a considerable difference. > > could raise issue with working group? > > obviously no client should interpolate white lines, where data has been provided. > > on the other hand there is a 'speed' issue, as interpolation takes cycles. Can you check with webkit trunk please? I can confirm a visual difference between Safari 5 and FF as well as Opera. But it seems to work in trunk. Just download a WebKit nightly.
Dirk, using r72487
Version 5.0.3 (6533.19.4, r72487)
filed as errata: define pixel interpolation when scaling http://www.w3.org/Bugs/Public/show_bug.cgi?id=11417