Three key visualization software - Display button on your computer screen

Recording software tutorial when needed, in order to better teaching results, we want to display on the screen of our key
recommend two visualization software here

1. KeyCastOW :
   open-source software platform under the window.

2. Carnac :
   the same is the software platform under the window, but the software does not support crtl, alt, shift and display fn (do not know the problem is not the finished version I used).

3. recommendation mac platform keycastr