iPhone 6 Screens Demystified

2- I think this is doubtful. The first time I saw a WWDC presentation about Resolution Independant graphics was in 2003 (maybe 2002.) Apple's been preparing for this time for a over a decade. The iPhone just was a bit too skeumorphic in its early versions resulting in a focus on raster assets rather than vector.

Either we're all going the Paintcode way (authors of this post) or Apple is going to have to start taking CSS or SVG or some vector format for its assets.

I think this is more likely than tying displays to a rigid multiple of the original iPhone screen size.

Displays are cut from larger pieces of display material at a given PPI. So Apple focused on perfecting a 163PPI display material and then tended to use it on multiple products. They'd do the same thing for the retina display material as well (I think at one point the iPhone and iPad used the same display material and it was just cut to different sizes in making the display)

Apple could do this because they work so closely with their display manufacturers and they care so much about fidelity. It just happened that doing rigid multiples of the original display size was convenient for software as well.

However, displays have become more commoditized, especially retina resolution ones (at the time it was introduced, Apple was the only one shipping these kinds of displays in such volume) and Apple's volume has only increased over the years.

So we're seeing a shift to more commodity display production, I believe, because the commodity market has caught up with Apple's standards. Beyond 300 pixels per inch there isn't much advantage to higher density.

But there is a huge advantage to unit volumes of a display also used in portable TVs or whatever.

The software cost of downscaling isn't significant at this point so it is an economic change.

Tying the size and density of your display to software needs-- especially points that are arbitrary to begin with (as they are based on the original iPhone) seems silly and outdated.

Heh. Yes there will be, most notably on webpages, for example those with box borders defined as "1px solid" lines. The lines will look fuzzy and unequal. Check the last image at http://www.paintcodeapp.com/content/news/2014-09-11_iphone-6... : it shows a "1 CSS pixel" line rendered as 2 black lines + 2 grey lines (one of the greys is very, very light). Some lines will not be interpolated the same way: some will be 2 black lines + 1 grey line, some will be 1 black line + 2 grey lines, and the shade of the 2 greys will be unequal and will vary depending on their precise alignment on the 1080p physical grid. The end result is that some lines will look slightly thinner/lighter or slightly thicker/darker than others. Heck, on my Nexus 5 which has an even higher PPI (445 PPI) than the iPhone 6+ (401 PPI) I can still clearly notice this effect, when holding the phone at arm's length (and I don't even have 20/20 vision), when simulating the downsampling that the 6+ is going to have to do. I can do it by zooming out[1] to simulate an effective pixel ratio of ~2.61, which is equivalent to what the iPhone 6+ is really doing graphically (1080 physical pixels wide / 414 logical pixels wide = ~2.61).

Contrast this with most Android devices where it is possible to get pixel perfect rendering because most (but not all) of them use a non-fractional pixel ratio (1.0, or 2.0, or 3.0, or 4.0) and to my knowledge none do downsampling (though with thousand of devices on the market I am sure 1 or 2 obscure models do it).

[1] If you have a 1080p Android device with a pixel ratio of 3.0 (eg. Nexus 5, LG G2, Galaxy S4, HTC One M7, etc), you can simulate the downsampling of the iPhone 6+ by zooming out in your browser by a factor of 360/414 = 0.8696

Edit: I did NOT downvote you. I agree that for many apps it won't be noticeable, but it will be in some apps. Many users spend a lot of time in the browser, and many sites use 1px lines, and they will be a distracting artifact (unless Apple implemented a special hack to interpolate 1px lines in the browser - maybe Safari bypasses downsampling and forcibly rounds them up to 3 physical pixels, but then what about other browsers?)