[whatwg] I believe source rectangles for HTML5 Canvas drawImage are specified incorrectly

Rik Cabanier cabanier at gmail.com
Wed Dec 12 10:24:26 PST 2012

On Wed, Dec 12, 2012 at 10:16 AM, Ian Hickson <ian at hixie.ch> wrote:

> On Wed, 12 Dec 2012, Rik Cabanier wrote:
> >
> > What would be the next step? Should we define a new version of drawImage
> > with the extra parameter?
> At the WHATWG, the process, insofar as there is one, is that the spec's
> editor (in this case me) goes through the e-mails on a topic and edits the
> spec based on the feedback and based on how much vendor buy-in an issue
> has.
> On this particular topic, I've only heard interest in implementing this
> from one vendor, Google, so adding support to the spec at this point is
> probably premature. If other vendors are interested in implementing
> something for this (a feature to make drawImage scale subsets with
> clamping at the source rectangle rather than the original image), I
> encourage them to indicate this on this thread.

> > If so, we probably want the description of the existing drawImage call
> > to change so it leaves the resampling issue undefined unless WebKit is
> > OK with changing their current behavior.
> Leaving the spec undefined is not acceptable. :-)
I agree.  What I meant to say that the spec should specify that resampling
behavior is undefined with the existing API.
It would of course be best if WK would fix their code so it follows the
current spec description and instructs developers to use the new parameter.

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