[cairo] Gradient mesh rasterizer

[Adrian Johnson]

Bill Spitzak wrote:
> Can the patch have any number of sides or is it required to have 4?

Internally patches are required to have 4 sides. Sides can be 
degenerate. If less than 4 sides are specified cairo will fill in each 
missing side with a cairo_pattern_line_to() to the first point in the 
patch. See for example the mesh-gradient-conical test that draws a 
conical gradient using circular sectors consisting of 2 lines and a 
Bézier curve.