Check the FPS in a C + + program

[Guest]

Hello everyone, I hope not to have the wrong section. I'm writing a small tool to manage the scaling of the ATI video cards with open driver (Radeon). To do this I need to know the fps of one element in the system (for example plasma-desktop). You know if there is a method in libraries qt4 or kdelibs to return it? there another way for know it?
Thanks to all for the help and sorry for my bad english

[OneLine]

The Plasma is having the "ShowFPS"



KDE System Settings > Desktop effects > All effects - Tools > ShowFPS


Maybe the sources (+ KDE docs) or the KDE/Plasma developers can help.