How to programmatically determine native pixel resolution of Retina MacBook Pro screen on OS X?

Question

Given a CGDirectDisplayID returned from

CGError error = CGGetActiveDisplayList(8, directDisplayIDs, &displayCount);

for the built-in s

Answer 1

I think the best approach is to enumerate all of the display modes (including the 1x modes) and find the biggest 1x mode's dimensions.

You would use CGDisplayCopyAllDisplayModes() and pass a dictionary with the key kCGDisplayShowDuplicateLowResolutionModes mapped to kCFBooleanTrue as the options to get all of the modes. You can test that CGDisplayModeGetPixelWidth() is equal to CGDisplayModeGetWidth() to determine which are 1x.