Engadget says yes. Daringfireball says no. Engadget says we’re both right, kind of. Daringfireball says nah, I still think I’m right and you’re just wrong.
It comes down to “pixel perfect” UI graphics. In short, you can pixel-double a UI without making it look any worse than native resolution, but you can’t upscale by a fraction. Or can you?
Bearing in mind that in “real life” the upscaled image would be displayed at reduced size and that the text would need not be upscaled (the single ugliest thing here is the WiFi signal strength indicator, which also wouldn’t be upscaled). I think we could actually live with this level of display quality.
Additional Note: the bitmap in the lower portion of the clipping is a screenshot that was pasted into the document and scaled, so you’re looking at a bitmap that’s been scaled from its native size down and then up — were this an actual 1.25x UI scale the bitmap would only have been scaled once and would likely be razor sharp.
So I think Engadget may be right.
On the Mac Observer discussion thread on this very same topic, someone links to a screenshot of developer guidelines presaging 2x resolution iPad icons for “universal” iPad apps. This is taken as “proof” that the iPad’s screen resolution is doubling, which I think is simply wrong. When Mac OS X first shipped icons were 128x128px with developers encouraged to provide scaled down versions in powers of two (64×64, 32×32, and so forth). Currently it’s 512x512px. An iPhone 4 is probably a more capable computer than a 2001 desktop Mac, and they were perfectly capable of scaling icons down to arbitrary sizes, so I don’t think this tells us anything.
If the iPad ships with a “retina” display, I suspect it will need to be 1.5x linear resolution, i.e. 1536x1152px. Scaling down graphics by 3/4 is something GPUs do very well and very cheaply. (And scaling them up by 50% is just as cheap and also quite good.)
Gruber & Benjamin — You Ignorant Sluts
On The Talk Show Gruber and Benjamin discuss how horrible a one pixel line would look scaled by 1.5. Here’s an absolute worst case scenario: single pixel black lines on a white background scaled up using the bicubic option (which is all but a free operation on most GPUs).
Note that this is scaling up by 50%, not scaling up resolution by 50% while keeping size constant. If you squeeze this image back down to the original size it will look even better.
I don’t think the iPad needs more pixels, and in fact there are advantages in keeping the resolution lower, but there’s seriously no technical or aesthetic obstacle to increasing resolution by a sensible factor and scaling stuff up.