Mouse coordinates in Objective-C?

Question

What is the difference between these three methods of getting mouse coordinates:

• [NSWindow convertBaseToScreen]
• [NSEvent* locationInWindow]
• [NSWindow mouseLocationOutsideOfEventStream]

I already checked the documentation, but the descriptions were too technical. Could someone explain the difference between these three in simpler terms?

Answer 1

Every window and every view has its own coordinate system, which (unless you've modified it) starts at (0, 0) in the bottom-left and counts up and to the right. -[NSEvent locationInWindow] gives you the location where the event took place the window's coordinate system (that is, (0, 0) is the bottom-left of the window). -[NSWindow convertBaseToScreen:] takes a coordinate in the window's coordinate system and converts it to screen coordinates, so that (0, 0) now means the bottom-left of the whole screen.

-[NSWindow mouseLocationOutsideOfEventStream] gives you the location (in the coordinate system of the window you send it to) where the mouse is right now, unrelated to any event. This is rarely useful information.