[cairo] surface matrix semantics?

Vladimir Vukicevic vladimir at pobox.com
Sat Apr 10 00:13:31 PDT 2004


As usual, the pieces clicked into place 30 seconds after actually 
sending the mail.  A matrix attached to a surface obviously needs to 
transform operations done to that surface -- so a scale of 0.5 set on a 
surface would mean that any rendering to it would happen at half-size. 
We should be setting the matrix on the drawing destination surface, not 
the source.  Right? :)

	- Vlad

Vladimir Vukicevic wrote:
> Howdy,
> 
> I'm a little unclear on how matrix transforms on surfaces are being 
> applied -- it seems that when I apply a matrix to a surface, and then 
> use that surface as a pattern, the visible result I get is the inverse 
> of the matrix that I applied, which is not what I'd expect.  Are the 
> matrices on surfaces intended to transform surface-local coordinates to 
> world coordinates?  Or to transform world to surface-local?
> 
> Thanks,
>     - Vlad





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