When it comes to Apple's Retina displays there's a bit more to it than what you're used to:
- when OP says 1440x900 he means the pixel doubled version. All GUI lengths / fonts have the size of their 1440x900 versions, but there are twice as many pixels, enabling high resolution graphics and fonts. It's basically a crotch because Apple never got around to make their OS resolution independent, however from a programmer's standpoint it's actually not that bad, you just have to specify images with @2x postfix in the filename.
- higher resolutions are not scaled in the same way you're used to. They're actually rendered internally at double the resolution after which they're overlayed with the screen's native grid for some interpolation-like process. The result is vastly better than what you know from usual screen interpolation, it's hardly noticeable actually.
- when OP says 1440x900 he means the pixel doubled version. All GUI lengths / fonts have the size of their 1440x900 versions, but there are twice as many pixels, enabling high resolution graphics and fonts. It's basically a crotch because Apple never got around to make their OS resolution independent, however from a programmer's standpoint it's actually not that bad, you just have to specify images with @2x postfix in the filename.
- higher resolutions are not scaled in the same way you're used to. They're actually rendered internally at double the resolution after which they're overlayed with the screen's native grid for some interpolation-like process. The result is vastly better than what you know from usual screen interpolation, it's hardly noticeable actually.