Why can't I get the pixels of a window that isn't visible on screen?
If the window isn't visible on the screen, then the pixels simply don't exist. The Windows painting model follows the principle of "Don't save anything you can recalculate". Consider: You have a 640x480 display in 16-color mode. That's 150KB of video memory. Take four copies of Notepad and maximize each one. If each of those copies of Notepad req...