| Do you have a source for that? Because I'd love if that were true, but every explanation I've seen contradicts that. The default isn't more space, as you write -- it's actually less space, for bigger elements. Which is why you would need to render at more than 2x. It does, indeed, scale up -- there are plenty of articles from when Retina's scaling options came out that state it does lead to a slight amount of blurriness because of this. To be clear, under Display > Scaled, the "More Space" option is true 2x retina, while "Default" through "Larger Text" are the ones that upscale. You can actually verify this yourself -- it you take a screenshot of any UX element at "More Space", and then take a screenshot of the same element at "Larger Text", they're pixel-for-pixel identical. For everything less than "More space", MacOS is scaling up. |
You are correct that if you go down to the "bigger text" side of things that it does scale things up, and for those sizes using 3x would give a sharper image. I hadn't even considered that though because I think most people think either the exact 2x retina resolution is fine, or if anything they want more space. The only people who would use the "bigger text" option are probably people with poor eyesight in which case it doesn't matter if its slightly more blurry.
EDIT: see screenshot here: http://imgbox.com/uxcHERt3 Default for MacBook Pro 13" is "Looks like 1440x900" which requires rendering at a resolution of 2880x1800, which is then scaled DOWN to the native resolution of 2560x1600.