from Hacker News

Retina display Macs, iPads, and HiDPI: Doing the Math

by tuhin on 3/2/12, 5:24 PM with 26 comments

• by ebbv on 3/2/12, 8:38 PM

  Mostly a good article and I agree with his main points, but I have two big disagreements.

  - Viewing distances. I only sit about 16-18" away from my 13" MBP screen and only about 24" from my 24" display. This varies obviously as I don't sit in a locked position all day, but I think he's erring a bit too high on estimated view distance, which means his necessary resolution to reach "retina" level is too low.

  - Screen size. Right now the 13" MBP I'm staring at has a very significant bezel that I would like to see mostly go away in an upcoming model refresh. The iPad's bezel makes sense since it's meant to be held in the hand. The MBP only needs enough bezel to fit the camera up top and needs none on the sides or bottom of the screen.

  But yes, his overall point that Apple does not need to go so far as screen doubling on laptops and desktops to achieve pixels that are indistinguishable to the human eye is correct. I just think the resolution at which that point is reached on laptops and desktops is a bit higher than what he's calculated.

• by robomartin on 3/2/12, 9:01 PM

  The landscape is getting a little messy for app developers. Not saying this is bad. It's just a fact.

  Today you have to deliver .png, @2X.png and *~ipad.png image sets with your app. And, there is no off-the-shelf way to reuse @2X images with the iPad when in most cases they'll work just fine. You can, but it requires creative coding.

  Still, this results in app packages that are bloated with image assets in triplicate and now soon to add a fourth version.

  If you build a universal app it seems that even someone downloading your app onto an iPod Touch is going to end-up with @2X, ~ipad and ~ipad2X (or whatever) images that the app will never use.

  Maybe this is the beginning of the end of the universal app?

• by seanalltogether on 3/2/12, 11:39 PM

  "Retina Display" should have a very clear definition. It should refer to resolution at which anti-aliasing becomes unnecessary. Anti-aliasing is rightly classified as a hack placed on top of modern drawing systems, and one of the reasons that many games don't support it out of the box. With a high enough resolution, anti-aliasing technology will become irrelevant.

  This is going to be different for each resolution depending on the distance that you view it at, I built a quick image that you can test this on. http://dl.dropbox.com/u/1437645/alias.html Put that on your phone or desktop and see how far you have to step back before the aliasing affect disappears

• by alok-g on 3/2/12, 8:26 PM

  From OP: "makes a solid argument for why an iPad retina display must be pixel-doubled -- i.e. 2048×1536 -- and not some intermediate resolution (just as was the case for the iPhone 4 before it). Anything else means every single existing app either has to re-scale art assets -- resulting in a fuzzy display -- or let them appear at a different size on-screen -- resulting in usability problems as the tap targets are resized. This is because every single existing iPad app is hard-coded to run full screen in 1024×768."

  Doesn't this suggest that Apple is getting bitten by backward compatibility to the mass of pre-existing apps, just like Microsoft got stuck with the mass of existing software running on Windows (and also actually users who get too used to existing UIs/UX)?

• by spitfire on 3/2/12, 6:05 PM

  This is a very good post. One I've thought about in a different context before: How much bandwidth/resolution do we really need.

  The human senses have an upper limit of resolution, once we reach that limit further progress is irrelevant. So once everyone is streaming netflix at limitx2, Where does further bandwidth/storage demand come from? Growing populations? There's a limit to that growth. "big data"? Hardly.

  We're rapidly approaching the point where individuals' need for further storage is exhausted. I think it'll be somewhere in the 10-100PB range. Which is pretty damn close.

• by joejohnson on 3/2/12, 8:26 PM

  This is a great post. If an iPad 3 has the "retina" display with resolution 2048×1536, I still think that a similarly high-resolution display will follow soon after for the soon-to-be-unified MacBook Pro/MacBook Air lines. If these high-resolutions screens are available at 9.7" for the iPad, it's hardly a stretch to manufacture them at 13" with a slightly reduced DPI.

• by wmf on 3/2/12, 9:58 PM

  There's an elephant hiding behind "UI elements would look proportionally larger": such a non-doubled Retina display would show less information than the old non-Retina one. This makes perfect sense in the Lion (and Metro and Unity) single-window world, but not for people who do work.

• by crgt on 3/3/12, 6:32 AM

  Is anyone else wondering about speed/performance issues when scaling up iPad graphics like this? Apple must have a hot new (A6?) chip up its sleeve that will enable performance on par with what you get from an iPad 2 now while also smoothly handling the larger images necessary for an iPad retina display. If not, what's the point outside of HD movies? Who cares about retina display if graphically intensive apps all chug? Or if devs have to use non high res images in order to preserve performance... Will be interesting to see how it shakes out.

  Here's hoping for an awesome chip that will make all of the graphics production rework worth it..

• by ewanmcteagle on 3/2/12, 7:57 PM

  This can't be correct when it comes to the larger screens. I found the text on the iPhone 3G to be fuzzy but not on the iPhone 4. I don't like Apple's antialiasing but on the iPhone 4 it doesn't matter anymore. Antialiasing becomes irrelevant. However, my 17 inch Macbook still has text that looks fuzzy to me and the antialiasing is still bothersome. I'm really hoping that there is some increase in resolution for the larger displays coming.