[cairo] clipmask of multiple rects in different angles
Enrico Weigelt, metux IT consult
enrico.weigelt at gr13.net
Wed Jul 20 11:37:27 UTC 2016
for my widget toolkit (*1), I'd like to repaint only those screen
sections that are actually changed. Each widget can have subwidgets
(theoretically unlimited recursion), which can be mapped in arbitrary
The rendering currently goes like this:
* each widget has some paint() operation, which just renders into an
* it doesn't actually draw to screen, but instead recorded into a
pattern (where also the already collected patterns of the subs
are painted into)
* finally, the pattern of the root widget (which then aleady holds
the complete scene) is painted onto screen
When individual widgets need to be repainted, their regions (in case
of moving, the corresponding regions in the parent) are invalidated.
These regions are then passed up the hierarchy with the corresponding
transfomations and finally collected in an list. (rects + matrices)
Now I'd like to create a clip, so only these rects are actually painted.
How can I achieve that ?
More information about the cairo