[whatwg] [WebApps] canvas transform()/setTransform()
Ian Hickson
ian at hixie.ch
Tue Jan 16 16:37:45 PST 2007
On Thu, 28 Dec 2006, ¹õß·¹ä»Ö(KUROSAWA, Takeshi) wrote:
>
> Web Application 1.0 adds the transform() and the setTransform() to the
> canvas 2d context. The conversion of the arguments of these methods to
> the matrices is described in the section 3.14.6.1.2.
>
> > The transform(m11, m12, m21, m22, dx, dy) method must multiply the current
> > transformation matrix with the matrix described by:
> > m11 m12 dx
> > m21 m22 dy
> > 0 0 1
> >
> > The setTransform(m11, m12, m21, m22, dx, dy) method...
> - http://www.whatwg.org/specs/web-apps/current-work/#transform
>
> However, this is repugnant. And it isn't compatible with many graphics
> systems. So the matrix should be
>
> m11 m21 dx
> m12 m22 dy ... (b)
> 0 0 1
>
> In addtion, the rhino-canvas implements both methods. It uses the matrix (b).
> http://rhino-canvas.sourceforge.net/
I have fixed the spec as you request. Sorry for the delay in responding.
On Thu, 28 Dec 2006, Charles McCathieNevile wrote:
>
> In particular, this would make for easy compatibility with SVG
> transformations, helping authors to copy them from one to hte other
> format and back.
Indeed.
On Mon, 15 Jan 2007, Stefan Haustein wrote:
>
> could somebody please clarify whether the unusual parameter order is
> intended -- or simply a bug in the specification?
It was a bug in the specification.
Cheers,
--
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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