Check the Lazarus and fpgui/fpgfx widget sets for FPC.

They are more or less what you want to do, (independant library to qt, gtk, some also xlib and win32 GDI) and maybe you can convert them to GPC objects style.

Thanks, looks good. But for me it is no problem to write in another language then Pascal since the graphical layer is written as a sub-layer.

www.freepascal.org/fpgui www.freepascal.org/lazarus

Personally, I think that you'll have to switch to GTK because of the reason nearly everybody uses GTK: because of the license of QT (not free!)

Maybe, but it is for a company. And I think it is no problem for them to pay. It will be non open source, non-free software. Do you know how this works in according with GCC, GPC an GTK+ (GPL?).

Borland uses QT, but paid the fee's. (so if you buy Delphi for Linux, you have a license to use QT, and develop and deploy programs), so that is a different category.