What does this tool do?

[jbbqqf]

I was happy reading the README because you and I wanted to solve the same issue:

If you are using Chromium browser for the graphic interface of your application, as I do, you may want to show some graphics and text overlaying the video being played with OMXplayer.

So I compiled fox.cpp and ran it while omxplayer is playing a video. What I see is a grey overlay (due to the alpha) on top of the video.

However, I don't find other info in the README / sources about what to do to display an actual X window. At first I thought fox would paint the screen as it is visible "under" omxplayer on top of it but it doesn't seem so.

What am I missing?