xlib feasibility question

[DanielWaterworth]

I'd really like to do some usability testing, and being able to do eye-tracking would be really useful. However eye-tracking cameras aren't viable for me, so I'd like to write some software that blacks out the entire screen except a circle around the cursor so that I can just record the cursor position. Is this possible using xlib?

[lkjoel]

I'd really like to do some usability testing, and being able to do eye-tracking would be really useful. However eye-tracking cameras aren't viable for me, so I'd like to write some software that blacks out the entire screen except a circle around the cursor so that I can just record the cursor position. Is this possible using xlib?
What programming language?
The only way I can suggest is to actually change the code of the application itself.
If it was another software, I don't think functionality of your other application would work.

[DanielWaterworth]

I don't want to have to change the code of the software. It's not possible then?

[lkjoel]

I don't know if it is possible to use xlib.
I am not a C/C++ programmer, but I do know a lot about what is possible to do with it.
But check the documentation.

Best Regards,
lkjoel.