Disabling the ability to screen shot and prtscr

I've already disabled right click on my  site, but I'd also like to disable screenshots. I've seen this done for many websites in the crypto world and wanted to implement  it on my site. If disabling it isn't an option, i'd like to cover the contents with a black overlay when screen shots are taken so that the photo is just a pure black void. how would i code this please 

Can you share link to a website where you see this feature?