Those pictures you put up don't do the iPhone4 display justice. I've seen it up close, and I think there's a pretty big difference. But I think I agree with your conclusion: 960x640 would be overkill on the Pre's 3.1" screen. I think the Pre's pixel density is somewhere in between the 3GS and 4 pixel densities. Oh heck, let's just do some math.
Originally Posted by wellwellwell11
Assuming square pixels...
3.5" 320x480: (320c)^2+(480c)^2=3.5^2
pixel density=1/c=164.8 pixels/inch
3.5" 640x960: c=sqrt(3.5^2/(640^2+960^2))=.003033 inches/pixel
pixel density=329.65 pixels/inch3.1" 320x480: c=.005374 inches/pixel
pixel density=186.1 pixels/inchJust for the heck of it, what would 480x800 look like on the Pre's 3.1" screen?
3.1" 480x800: c=.003323 inches/pixel
pixel density=300.95 pixels/inch3.1" 640x960: c=.002687
pixel density=372.2 pixels/inch <--I'm not sure this is possible with current tech.So the Pre's pixel density would come pretty close to the iPhone4's retina display if it had a 480x800 resolution. Of course, for square pixels, the Pre's screen would have to be a little bit longer, since 480/800 is not the same ratio as 320/480. So there are some challenges there. Then there are the PDK apps--you can't do something simple like just doubling each pixel to fill the screen. You would have to do 3 pixels for every 2. It could be done, but it's a little bit messier.
Anyway, after all of this, when you take everything into account, if the Pre 2's job was to basically be the same phone, even to the extent of using the same Touchstone back, there really wasn't much they could do with the screen. Possibly they could have gone to 480x800, but you could easily argue that back in the spring when they were putting this guy together the extra effort wasn't worth it. It is very likely that the design for the Pre 2 was completed prior to the completion of the acquisition, which makes it unlikely that HP had any involvement (or cash) in this device. In other words, the design was very much cost constrained.
At least, those are my two cents.