Just curious...
Are you using an OpenGL directdraw surface for the graphics emulation in
Qemu?
If not, then consider the benefits:
1. It is much faster than any native graphics 2D/3D primitives like
Windows GDI
2: It gives full control over things like window or fullscreen mode in
any (almost) resolution and color depth.
3. It is operating system independent.
4. It handles things like RGB, BGR, 24bit, 15bit, 16bit, 8bit, alpha
channel etc in hardware, all you have to do is select the pixelformat
you like to use for the buffer and OpenGL does the rest - lightning
fast, minimum CPU-load.
[...]