[Etoys] Nepalese support: making progress

[Bert Freudenberg]

Am 25.06.2008 um 07:48 schrieb Yoshiki Ohshima:

>  We are making another progress on the text rendering support with
> Pango.  This time, I'm even comfortable to mention it publicly!


One reason for the performance degradation is that the Pango rendering  
methods flush the whole screen. That is, for every little string there  
is a BitBlt of 1200x900 pixels converting from 32 to 15 bpp. To only  
flush the affected area, you need to give a rectangle parameter to  
#finish:.

Also, for each string/paragraph it actually allocates, draws into, and  
discards a 1200x900x32 Cairo bitmap surface. I did not measure how  
expensive that is, but it could be avoided by reusing one Cairo  
surface for all rendering (the affected region will have to be cleared  
in between of course).

- Bert -