[Gambas-user] jpeg performance

[Rob Kudla]

On Tue January 3 2006 14:02, nando wrote:
> Shelling to a 3-line Shell script (a different one for each
> camera):

You might also consider using "convert" or some other ImageMagick 
tool run from a shell without a WAIT to do the stretching, so 
that 4 of those can be done at the same time too.  It won't be 
any faster than Qt's stretching, but at least your program isn't 
frozen while it's happening.

Also, using a drawing area is slower than using two picture boxes 
for each image and showing/hiding them (basically page flipping) 
in my experience.  I wrote an app to capture and display frames 
from a security camera (by shelling out to some v4l capture 
utility), and I used that approach.  Qt is still slow enough 
that when you make the picture full-screen you can see the 
redraw, but short of redoing it as an SDL app I don't see any 
other option.

When gb.qt.opengl is mature, you might look into that for faster 
scaling as well.

Rob