Decorationless Window - How??

edit

Hello,

My display's resolution is 1920x1080. I want to show images which are size of 1920x1080 on this display. But window decorations (titlebar and borders) eat into my display area. How can I overcome this? What is the best way to go fully fullscreen?

Setting CV_WND_PROP_FULLSCREEN to CV_WINDOW_FULLSCREEN removes titlebar but borders remain. :(