When working with multiple screens and mouse location in Cocoa you have to go through converting the point coordinates to the current screen coordinates.

For example if you have a second monitor on the left and you want to get the mouse position relative to that screen, [NSEvent mousePosition] will return something like (-1200, 130), which is often not what you want. This class provides three simple methods to simplify conversion of points to the current screen coordinates:

    /* 
     Returns the screen where the mouse resides
    */
    + (NSScreen *)currentScreenForMouseLocation;

    /*
     Allows you to convert a point from global coordinates to the current screen coordinates.
    */
    - (NSPoint)convertPointToScreenCoordinates:(NSPoint)aPoint;

    /*
     Allows to flip the point coordinates, so y is 0 at the top instead of the bottom. x remains the same
    */
    - (NSPoint)flipPoint:(NSPoint)aPoint;


License: MIT