How to get a desktop picture through the program?

Question

C++ / C#

Hello!
I want to get a desktop picture through Unity in the program and then do something with it. How can this be done? Or how to replace the background if you can't get it?
PS And a follow-up question: how to get the PC username?

Answer 1

https://www.whitebyte.info/programming/why-being-a...
https://www.dreamincode.net/forums/topic/124884-ge...
https://msdn.microsoft.com/ en-us/library/system.en...
Well, like the first links in Google.