[webkit-dev] Canvas rendering changes between Safari and Nightlies

Oliver Hunt oliver at apple.com
Sat Mar 29 15:58:22 PDT 2008

Without the full source, or a reduced test case it's we can't see what  
the bug is, so merely looking at code won't help.

Rather than using this list to report the bug though, I'd encourage  
you to file a bug at http://bugs.webkit.org as that
means the report won't be lost, and many people will be able to look  
at it and work out what is happening.


On Mar 29, 2008, at 12:47 PM, Dimitri Bouniol wrote:

> I am using a canvas to render images at a perspective on my site by  
> rendering each line of pixels at a different scale.
> The canvas object is all the icons that appear at the top of the  
> page in the grey bar.
> In Safari (3.1 and below), everything renders quickly and looks  
> normal, but in recent Nightly builds, rendering time is  
> significantly increased and rendering looks very bizarre.
> I think it has something to do with drawing and scaling images using  
> transforming methods, but I'm not sure, and was wondering If someone  
> could take a look at it so I can locate the issue and either file a  
> bug of fix my own code.
> Site: http://appkainime.bouniol.homeip.net/
> Javascript: http://appkainime.bouniol.homeip.net/js/master.js
> Methods of interest:
> - drawAppFlow()
> Calls drawInContextWithPerspectiveAndArg several times at different  
> positions with each image to be drawn at a perspective.
> - drawInContextWithPerspectiveAndArg(drawFunction, ctx, x, y, z,  
> width, height, arg)
> Draws the drawFunction(ctx, arg) in the context ctx using the one- 
> point perspective at (x, y, z), by calling drawFunction(ctx, arg)  
> for every vertical pixel line, then clip, scale, and apply shading  
> to the result accordingly so a perspective is acheived.
> drawFunction is always drawImage(ctx, image)
> arg is an Image object to be passed to drawImage
> - drawImage(ctx, image)
> Draws the image in the context ctx with a shadow, or if the image is  
> not yet loaded, draws a grey box instead.
> Hope someone could help me find the issue for this.
> --
> 定魅刀利
> Dimitri Bouniol
> dimitri008 at mac.com
> http://web.mac.com/dimitri008/
> _______________________________________________
> webkit-dev mailing list
> webkit-dev at lists.webkit.org
> http://lists.webkit.org/mailman/listinfo/webkit-dev

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