[cairo] How to make stipple pattern as source

[Daniel Goldman]

Can someone suggest how to make a stipple pattern (or other tiled pattern) as a 
source? Something like:

oxoxoxoxox
xoxoxoxoxo
oxoxoxoxox

Or

ooxxooxx
xxooxxoo
ooxxooxx

After looking around cairo web site a lot, the only thing I saw was 
cairo_image_surface_create_from_png () with an existing png file with pattern. 
I'd rather create the pattern from within cairo, but don't know which functions 
to use. I don't want to reinvent the wheel or do this an inefficient way.

I write to both pdf and png surfaces.

Thanks,
Daniel