I’m searching now for a while but can’t find an entrance…
The application should behave like a ruler app which is always in front of all apps and does not have a window. I want to draw things directly on the screen.
Would be great if someone could help me out with some keywords to search for or a concrete step into.
Thanks in advance.
Create a borderless transparent NSWindow and draw your content inside it. There are many examples for creating those around.
Use setLevel: to control how the window floats over other windows.