[cairo] Fast text rendering

[michael at cubic.org]

Is there a good manual or book out there exclusively about cairo?

I was irritated, that for the xlib surface I get about 170 frames per
second for a text matrix of 20 by 20 with two digits of text and
for the xgl surface I get less than 1 frame per second.

> No matter what, you need to arrange your program so you don't *have* to
> draw 30 different letters every second. It should instead do a "what
> letter is it at now, if different than before draw it" method.

It is only draw when nessesary, but the worst case makes it nessesary to
draw them with 30Hz.

This is the reason why the 30Hz:
http://www.grandma2.de/help/en-us/image/Ref_Window_Sheet_DMX.png
This can actually be drawn to an image and then be mapped to the destination.

And its geting even worse with lots of dynamic changes:
http://www.grandma2.de/help/en-us/image/Concept_Effect_2.gif
http://www.grandma2.de/help/en-us/image/Ref_Window_Sheet_Fixture.png