Best Method for Minimizable Fullscreen Window

Question

Hi, I'm coding a short game in C++ and Win32, and I want to be able to make it in fullscreen with a fixed size. I also want the user to be able to switch focus between the game window and other windows as much as he/she wants without any weird screen glitches.

So far I know of the ChangeDisplaySettings function and creating the window with the WS_POPUP style at initialization to make it fullscreen. To detect the user switching focus to other windows by way of alt+tab or otherwise, what messages should I be handling on the window's WndProc or should I be using another function? When loss of focus is detected should I only call ChangeDisplaySettings(NULL, 0); or are there other functions I should call as well? And what method should I use to handle focus back into the window?

Also can anyone give me some info on how to make it work smoothly for different screen sizes?

Thanks for any help.

Answer 1

If you want an exclusive full screen window, use DirectX.

But I don't recommend it. Changing the display mode causes glitches, rearranges the users icons and so on. Whether done by you, or Direct X.

Rather create a normal window at your native res, and let the user maximize it if wanted.

Answer 2

You could also use the GDI+ library of Windows XP (and newer) to use hardware-accelerated stretching (draw in 640x480, let GDI+ resize it to the native resolution). Then you don't need exclusive mode of DirectDraw nor ChangeDisplaySettings.

Also drawing into a 640x480 big background buffer and bit blitting it on the drawing surface via StretchBlt can be a performant solution.