[whatwg] Compatibility problems with HTML5 Canvas spec.

Philip Taylor excors+whatwg at gmail.com
Tue Sep 25 14:19:47 PDT 2007

On 25/09/2007, Oliver Hunt <oliver at apple.com> wrote:
> Firefox 2/3 and Safari 2 clear the context's path on strokeRect/
> fillRect, this violates the spec -- but there are many websites that
> now rely on such behaviour despite the behaviour defined in hmtl5.
> This means that those browsers that match the current draft (eg.
> Safari 3 and Opera 9.x) fail to render these websites "correctly".

How hard would it be to get those sites fixed? If there are problems
in something like PlotKit or Reflection.js, which lots of people copy
onto their own servers, then it would be a pain to break
compatibility. If it's just sites like canvaspaint.org where there is
a single copy of the code and the developer still exists and can
update it, it seems a much less significant problem to break

> Unfortunately it isn't really an edge case as it's a relatively
> common occurance -- people expect that the rect drawing function (for
> example) will clear the path, so expect clearRect
> (myCanvasElement.width, myCanvasElement.height) to clear the rect and
> reset the path, and other similarly exciting things :-/

Firefox also resets the path on drawImage and putImageData, unlike
Opera and Safari 3 - do people depend on that behaviour too?

> --Oliver

Philip Taylor
excors at gmail.com

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