I want to get a screenshot of non visible or minimized window and save it as bmp. I know how to do it with visible window. It's easy. But get non visible is quite difficult. I have looked over Internet and didn't find any example. I know that Desktop Window Manager get window's thumbnails. DWM example But I didn't find any example how to convert thumbnail to bmp.
P.S. Please don't suggest me to bring window in front, get a screenshot and then minimize it.