[cairo] New to cairo, some questions
sloonz at gmail.com
Fri Jan 24 08:51:28 PST 2014
I’m trying to learn cairo, and there’s some thinks I don’t quite
understand. First, let’s begin with this simple program :
It is a simple animation where an arc rotates around the center. Now my
questions are :
* If I move cairo_create() and cairo_destroy() out of the loop, the
result is still the same. However, most cairo examples on the web (like
http://en.literateprograms.org/Hello_World_%28C,_Cairo%29) puts these
call outside the loop. Why ? What’s the difference ?
* Now if I just move cairo_paint() (and the first cairo_set_source_rgba
call) outside the loop, I expect the result to be an animation of a
circle being drawn. But that’s not what I get : I get no animation
at all. Why ?
* The same programe using EGL
(https://gist.github.com/anonymous/8600771) instead of plain X
surface doesn't draw anything. What am I doing wrong ?
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