How can I turn a video image created by winmm.dll to fullscreen? The answer could be simple: resize it to fullscreen. Yes I thought that way too. But there was a problem when I wanted to make it a fullscreen while the video was in paused mode. Normaly it worked, but , once in while, the image would not stretch to fullscreen even though the window size was stretched to fullscreen. There was no problem while the video was playing. So I thought that the problem would be solved if the video was resumed just before the resize process and paused again after the resize. But, no, it did not solve the problem.
Then I noticed that a stretch to 'maximized' window never failed. So I changed the fullscreen process to 2 steps of resizing. First maximize it and then stretch it to fullscreen. Bingo! The problem was solved. A small find, but big satisfation. The latest version of zPlayer adopted this solution.