How do I create a screenshot function?

I tried everything but the screenshot function for this app Im working on does not work. I tried many different screenshot methods but it still wont take any pictures. Please if anyone can take a look at this and help me out that would be so0o awesome

dropbox.com/s/7zy65f4f6qvhkji/DrawingMang.zip

What exactly have you tried? I don't see any attempts in your capx file.

Taking screenshot is pretty easy and there are lots of examples and tutorials.

scirra.com/tutorials/1087/using-nodewebkit-to-take-and-auto-save-screenshots-in-desktop-builds

scirra.com/tutorials/9553/screenshot-capture-to-email