What resolution programmers will get in Macbook Pro Retina

Question

Note: this question may not be suitable to SO, but I'd like to ask here because I want to hear from Mac OS X developers.

Macbook Pro Retina (MPB Retina) has a native 2880x1800 resolution. However, such native resolution is not directly exposed. Rather, resolutions like 1440x900 and 1920x1200 are provied as shown in the below figure.

I want to know what resolution programmers will see. Is it 2880x1800? Or, a reduced resolution?

I'm particularly interested in how Mac OS X handles such ultra display. There could be two approaches: (1) Mac OS X sets the 2880x1800 resolution, and then tweaks DPI scaling for all programs; (2) Just set lower resolution while having the original DPI setting. (simple)

Because I have no experience in writing an application for Mac OS X, I really want to see how Mac OS X handles this resolution, and what is the impacts for programmers to adapt retina display.

Answer 1

From what I know, in 1680x1050 and 1920x1200 Mac OS actually sets virtual resolution to twice as that (so 3360x2100 or 3840x2400 respectively) and then downscales to physical resolution 2880x1800. This allows resulting image to be quite sharp (there is a performance penalty though). What resolution a programmer see depends on whether application is Retina-enabled or not. Mac OS never changes DPI for apps.

Apple has provide an extensive guide on the topic. You can find it here: http://developer.apple.com/library/mac/#documentation/GraphicsAnimation/Conceptual/HighResolutionOSX/Introduction/Introduction.html