The Display

The most visible improvement of the new iPad is naturally its Retina Display. Originally introduced with the iPhone 4, the concept of an Apple Retina Display was created to refer to a display where the pixel density was high enough that the human eye, at a standard viewing distance, could not resolve or identify individual pixels.

Unlike traditional OSes, iOS doesn't support a laundry list of display resolutions. The iPhone was introduced at 480 x 320 (3:2 aspect ratio), while the iPad came to be at 1024 x 768 (4:3 aspect ratio). Rather than require iPhone applications be redesigned for a higher resolution iPhone, Apple simply doubled both the vertical and horizontal resolution for the iPhone 4—maintaining the same aspect ratio as the previous models, and only requiring higher quality assets, not a redesigned UI, to take advantage of the new display.

The iPad on the other hand always required a redesigned UI to make the most of the iPad's larger display and higher resolution. With a different aspect ratio, simply scaling up an iPhone app wouldn't work (although to enable backwards compatibility Apple did allow you to do just that). Admittedly Apple wouldn't want to allow such easy portability between iPhone and iPad apps as it wanted the extra effort to improve the quality of tablet apps.

The new iPad does what the iPhone 4 did and doubles both horizontal and vertical resolution: from 1024 x 768 to 2048 x 1536. All iPad applications work by default as developers don't directly address pixels but rather coordinates on the screen. Existing apps take up the full screen, and if higher resolution images are present they are used as they avoid the interpolation associated with scaling up an image designed for the original iPad resolution. For example, below we have a makeshift iOS icon in three different forms—10x7 native (72x72), upscaled to a 2x version using bicubic interpolation (144x144), and a 2x resolution version (144x144):

72x72
144x144 (Upscaled)
144x144 (Native)

The upscaled form looks good, but the 2x resolution version looks better.

More traditional OSes have always given you additional desktop real estate with increased resolutions. iOS simply gives you a better looking desktop. This distinction is arguably one of the reasons why the new iPad's display can be so polarizing. As consumers of high-end displays we're used to higher resolution going hand in hand with a larger panel size. Alternatively, we're used to a higher resolution enabling us to see more on a screen at one time. In the case of the new iPad, the higher resolution just makes things look sharper. It's a ton of work for an admittedly more understated impact, but it's the type of thing that simply had to be done.

Retina Display Enabled Apps

Apple has created such a healthy marketplace with the app store that developers are eager to quickly deliver apps with updated graphics for the new iPad. Sure enough, by the day of launch we saw several high profile applications with higher resolution assets for the new iPad. The motivation to have Retina Display support is huge as Apple is actively promoting those apps that have been updated for the new iPad via the app store:

These updated apps now come with larger image assets, which can increase the total app size. Not all apps will grow in size (e.g. Infinity Blade 2 simply renders at a higher resolution vs. using tons of new content, not to mention that textures are already heavily compressed) but some have/will. The retina burden unfortunately impacts all iPads as there's only a single app package delivered upon download. Even if you don't use them, the higher resolution retina graphics are there.

Note that iPhone apps will now load their Retina assets (designed for 640 x 960) rather than their normal assets (designed for 320 x 480) on the new iPad, resulting in a significant improvement in image quality there as well:

Games are a special exception to the 2x asset scaling of the new iPad. Applications that simply have their UI accelerated by the A5X's GPU do fairly well at the iPad's native resolution. 3D games are another story however.

If all you're doing is determining the color of a single pixel on the screen, not impacted by lights in 3D space or other transparent surfaces above the surface, it's a relatively simple and painless process. For the majority of what you're looking at in iOS, this is simply the procedure. The app instructs the drawing APIs to place a red pixel at a set of coordinates and that's what happens. In a 3D game however, arriving at the color value of that pixel can require quite a bit of math, and quite a bit of memory bandwidth.

Game developers have a few options on the new iPad. One option is to not update a game, running it at 1024 x 768 and rely on the iPad's scaler to upscale the image to 2048 x 1536. The game will take up the full screen, run faster than on the iPad 2, but it won't necessarily look any better. Low resolution content upscaled to a higher resolution display still maintains much of the aliasing you'd see at a lower resolution.

Another option is to render all scenes at the new iPad's resolution: 2048 x 1536. With four times the number of pixels to fill and only 2x the compute and memory bandwidth compared to the iPad 2, this will only work for fairly lightweight content. Not to say that it's impossible—even GLBenchmark's Egypt test, in its current form, actually runs very well at the new iPad's native resolution. Many stressful 3D games won't fall into this category however.

The third, and more popular option is for a game developer to render all frames offscreen at an intermediate resolution between 1024 x 768 and 2048 x 1536, then scale up to the panel's native res. So long as the developer maintains aspect ratio, it'll be possible to use this approach and get a good balance of higher resolution and performance.


Infinity Blade 2 for the new iPad Renders at roughly 1.4x the iPad 2's resolution, then upscales to fill the screen

Infinity Blade 2, for example, renders offscreen at roughly 1.4x the resolution of the iPad 2 before scaling up to 2048 x 1536 for final display. The result is a sharper image than what you'd get on an iPad 2, without sacrificing performance.

Game developers may choose to increase the level of anti-aliasing instead of or in combination with an increase in resolution. As we'll discuss shortly, Apple's A5X does come equipped with more GPU execution resources and dedicated memory bandwidth for graphics that would allow for an increase in quality without a corresponding decrease in frame rate.

The new iPad The Display: In Numbers
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  • zanon - Wednesday, March 28, 2012 - link

    In the article:
    Alternatively, we're used to a higher resolution enabling us to see more on a screen at one time. In the case of the new iPad, the higher resolution just makes things look sharper.

    The higher resolution does make smaller fonts readable. For something like an SSH session, that really will mean significantly more stuff can be on a screen at once.
    Reply
  • MobiusStrip - Thursday, March 29, 2012 - link

    A more useful change would be abandoning the ridiculous glossy screens. It's sad that Apple takes its cues from the plastic schlock being peddled at Best Buy, and participates in this fraud of shoving glossy screens down customers' throats. Reply
  • repoman27 - Thursday, March 29, 2012 - link

    The plastic schlock at Best Buy has a glossy plastic film applied to a cheap TN panel. Apple puts a piece of glass in front of their much more expensive IPS panels to protect them. The only way to make that glass (or the glass of the LCD panel itself) matte would be to apply an antiglare plastic film coating to the glass. These films have drawbacks (they block and scatter light making small details and text blurry.) The drawbacks become more exaggerated the farther the front surface of the glass is from the plane of the actual LCD.

    But you're right, it's probably Apple copying the design language of sub $500 laptops in order to somehow defraud the general public and force their customers to buy the products they actually produce.

    And seeing as how this discussion is about the new iPad screen, I'd like to point out that you're complaining about the lack of an antiglare coating on a touchscreen device... Strong work.
    Reply
  • Sabresiberian - Thursday, March 29, 2012 - link

    How is it fraud? Apple isn't, like, saying their screens are anti-reflective and then giving you totally reflective glossy screens.

    Many people prefer a glossy screen and simply aren't bothered by background reflections.

    ;)
    Reply
  • Henk Poley - Monday, April 02, 2012 - link

    Yes, Apple really should use Schott Conturan/Amiran/Mirogard antireflective technology.

    btw, not-glossy does not mean matte. Air is not matte either. Glass can be see-through too ;)
    Reply
  • Watwatwat - Monday, April 02, 2012 - link

    Nope, steve gibson has tested even using screen protectors on the new ipad vs not, it seems to affect the resolution at that level, matte might not be a good idea at all for high density display. Reply
  • KoolAidMan1 - Thursday, March 29, 2012 - link

    I wasn't initially blown away, but then after a day of using it every other display seemed bad in comparison. It is one of those things you didn't realize was needed until using it, now I want very high DPI in all of my monitors. Reply
  • menting - Wednesday, March 28, 2012 - link

    Is it just me, or do Shadowgun and GTA screenshots look more detailed in Transformer Prime than in the iPad? Reply
  • menting - Wednesday, March 28, 2012 - link

    nm..i just noticed that it's scaled up in new ipad, so it's definitely not as sharp.
    However, how can fps be fairly compared in this case then?
    Reply
  • TheJian - Wednesday, March 28, 2012 - link

    Basically because of the way Nvidia and Apple approach games so far, you can expect games on Tegra3 to just look better as they seem to aim for more graphics and fewer games (they spend money on fewer projects that produce better results), as opposed to apple who spreads the wealth but just ends up with more cannon fodder if you ask me :) You should get more variety on Apple I'd guess, but a better experience with fewer choices on Tegra3/Android. I like QUALITY over QUANTITY personally and hope Apple leans the way of Nvidia in the future. I would rather have 10 games that I'd play for weeks or months (if I'm playing on my hdtv through one of these I want better water, buildings etc) rather than games I fire up for less than 20 minutes as their just another angry birds variant and arguably useless on your TV.

    I want these devices to KILL the consoles next year and make MS/Nintendo etc give it up in 2015 or whenever the next revs should come. I hope they just realize we won't buy them anymore. DirectX11 on my phone/tablet and probably standard 25x14 resolutions by then (won't all be retina by 2015?) make a console purchase STUPID. This could be the merging of console/pc we need since phones/tablets rev yearly like pc's instead of 10yr console's stuck in stone stagnating gaming. Your phone as a portable console with xbox/ps3/pc gamepad support would be excellent. Pump it out to a monitor and keyboard/mouse setup and you have a notebook replacement too...LOL Now if they'd just put in a few extra cores by then that will disable if on their own screen but turn on when on a larger display like TV/Monitor and we have exactly what we want in both cases :)

    Pipe dreams? Retina is here now, and gamepads sort of. Next stop cores that only turn on depending on display output :) Awesome battery on the road, and great power in the dock at home pushing your 27in monitor. :) The 28nm versions by xmas of everyone's chips should come close to console power or surpass them. Interesting times.
    Reply

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