[cairo] polygon fill with patterns

[Stephan Siemen]

Hi,

I try to fill polygons (e.g. paths) with patterns of dots. I
have various areas with different properties where I want the
dot size, color and distance between dots reflect the properties.
I generate geographical maps of weather properties.

Since I have many areas (of very different sizes and shapes)
I am very much concerned about performance. What is the best
way to achieve this? Should I generate a (png) image and use
this as pattern? Or can I draw a pattern and use this? Latter
would be ideal because I could implement easily more patterns.

I looked at the examples and the only one I could get to work
is to use images for patterns.

Thanks in advance for any help!
Stephan