How to grab screen on thread?

[Alex Snet]

Hi!

I know how to grab screen in GUI thread:


QPixmap::grabWindow( QApplication::desktop()->winId() );


But how to grab the screen in another thread?
If I do it how i write before application returns this:


QPixmap: It is not safe to use pixmaps outside the GUI thread

[wysota]

Why would you want to do that?

[Alex Snet]

I wanna make a small OS screen capture utility.
If I shoots from GUI thread it stops at some time and I can't get more than 7 frames per second.

[Alex Snet]

Can I use OpenGL? Or it's a extra load for application?

[wysota]

Using another thread would only slow your application down instead of speeding it up. Making screenshots of the screen like that is a very slow operation - don't expect to get more than those few frames per second.

[Alex Snet]

And how I can make it faster? How I can get more than 15-20 frames per second?

[wysota]

Using platform dependant means. Such as XVideo on X11 (or take a look at sources of applications such as recordmydesktop).