[Cairo] Gradients

[Thomas Hunger]

On Saturday 04 October 2003 18:28, you wrote:
> On Oct 4, Thomas Hunger wrote:
>  > I did a linear gradient using cairo the way described in the OLS paper.
>  > Now I wonder if I want to do complex gradients, like interpolating
>  > between different "color-points" or a plain radial one, will I always
>  > have to use surfaces which I compose myself or are there already some
>  > thoughts on different ways to accomplish this?
>
> You've noticed the same things we have. The gradient technique we
> showed at OLS is a cute hack, but it can't do much beyond linear
> gradients.
>
> Keith and I have been looking at the PostScript support for
> function-based shadings. We should be able to figure out a way to do
> something similar.

Do you want to compose the gradient with trapezoids (and use some kind of 
parameter to control the smoothness of the gradient? The smoother the more 
trapezoids used)? 
If so, how could I tell XRender (IC) which color to use for the trapezoids? 
There is no color member in the XTrapezoid structure but I saw a 
#define X_RenderColorTrapezoids             14
in the XRender extension header?

regards,
Tom

p.s. sorry Carl for buggering you directly. 

>
> As always, contributions are welcome.
>
> -Carl