Get the internal macbook screen with NSScreen

Question

If I have an external monitor connected to my MacBook, how would I retrieve the MacBook screen?

Either of the screens could be the screen with the menubar and the dock. They could also have the same resolution, the same name etc..

Is it posible to determine it without requesting the user to unplug all screens except the MacBook screen?

Answer 1

You can use CGDisplayIsBuiltin() to find out if the display is builtin.

Example code:

int i = 0;
for(NSScreen* screen in [NSScreen screens]) {
    NSDictionary* screenDictionary = [screen deviceDescription];
    NSNumber* screenID = [screenDictionary objectForKey:@"NSScreenNumber"];
    CGDirectDisplayID aID = [screenID unsignedIntValue];     
    NSLog(@"Screen number %i is%@ builtin", i, CGDisplayIsBuiltin(aID)? @"": @" not");
    i++;
}