[Okular-devel] Slow painting on QImage

[Albert Astals Cid]

A Dijous 26 Octubre 2006 15:01, Tobias Koenig va escriure:
> Hi,
>
> after I've ported the OOo Generator to QImage yesterday I realized that
> painting on the QImage was 3x slower than painting on the QPixmap.
>
> Today I asked the Zack how this can happen and he explained that for
> rendering the text, the X server is still queried in current version of
> Qt4, so drawing text in a QImage is quite inefficient.
>
> One solution is to do all the paiting on a QPixmap and to the convertion
> to a QImage only once...
>
> Another problem we came accross here is that painting to a QPixmap or
> drawing text (which is rendered by X) is only allowed in the main thread!!!

Right.

> So we have a real problem with threaded generators. The poppler
> generator didn't hit this issue since it renders the font itself, or?

Right, poppler only uses Qt classes for the interfacing with poppler core 
classes.

Albert

>
> Ciao,
> Tobias