[cairo] path gradients and cairo
vladimir at pobox.com
Sun Apr 25 20:00:44 PDT 2004
David Reveman wrote:
> I think a "path gradient" pattern can be quite useful.
> Something similar to:
> cairo_pattern_t *
> cairo_pattern_create_for_current_path (cairo_t *cr);
> would be nice and we would probably need to add on or two functions for
> setting the center and surrounding color points, right?
Mmm. I was thinking of something like this, but I have a hard time
figuring out how you'd specify the colors. Concievably, the current
path could include curves and the like.. I'm not sure how you'd specify
what point to attach a color to. The "simple" implementation would be
cairo_pattern_create_path (cairo_point_t *points, cairo_color_t *colors,
int num_points) -- but this doesn't really fit with any of the current
API functions (especially considering there's no publicly exported
cairo_point_t nor cairo_color_t).
It also probably wouldn't make sense to extend paths to be able to store
color ops, so I'm not sure of the right way to specify the color data.
> There would be no problem in passing this pattern data down to glitz. I
> actually think it could be efficiently accelerated by the current
> version of glitz using non-rectangular clipping and the color triangles.
Good to hear! The non-accelerated/pixel-rendering case shouldn't be too
bad to implement, either; it should fit in cleanly within the current
framework in cairo_pattern.c.
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