( You should avoid creating UIImage objects that are greater than 1024 x 1024 in size. Besides the large amount of memory such an image would consume, you may run into problems when using the image as a texture in OpenGL ES or when drawing the image to a view or layer - http://developer.apple.com/library/ios/#documentation/uikit/...)
edit for clarity: don't manipulate images in the JPEG domain.
We didn't realize it could be circumvented with PNG's, that's an interesting idea, though it certainly hurts on the bandwidth side.
I expect the iPad3's high resolution to cause a lot websites pain on the bandwidth side. When it comes to the web, people aren't as picky with their high resolution desktop displays as they are likely to be with their iPads.
In this instance we're talking about 2 megapixel images, so the extra HTTP requests are not even going to register in the mix. With modern browsers pulling down 6+ parallel downloads, breaking the image up might make plenty of sense.
This doesn't explain why regular JPEGs are treated special though.
> JPEG images can be up to 32 megapixels due to subsampling, which allows JPEG images to decode to a size that has one sixteenth the number of pixels. JPEG images larger than 2 megapixels are subsampled—that is, decoded to a reduced size. JPEG subsampling allows the user to view images from the latest digital cameras.
JPEG block size is 16, so this must be an alignment related.
Do you have a problem with marketing in general? Is it a problem that Audi makes quattro cars or that Volkswagens have 4motion or BMWs have cars with 'x' in the model number? They only signify 4WD after all.
BTW, iPhone 4 is a 3.5 inch 640×960 resolution (326 ppi). N900 is 3.5 inch 800 × 480 resolution (267 ppi). Not that it matters either way.
Neither of your car manufacturer examples demonstrate this. However, when a certain US cellular carrier slapped a "4G" sticker on 3G technology simply to make their product appear competitive in the market that was not OK.
Similarly, implying to users the pixel density of their device matches the resolving capabilities of the retina, when actual scientific studies demonstrate otherwise, is not OK with me.
But the new iPad is 264 PPI.
Pixel density is only half the equation.
A subset of human retinas can discern a higher pixel density, in the same way that a subset of the human population is capable of running the 4 minute mile. It doesn't make us all professional middle-distance runners.
The majority of people don't even have 20/20 uncorrected vision much less the ability to discern the pixels on a Retina display.
That would be a nice explanation if it actually fit the numbers. That subset of human retinas actually turns out to be 75% of the population. As for average vision, 35% of people can see better than 20/20 with no aids, and once glasses/contacts are added this number jumps significantly.
Apple's displays may well be termed true "20/20 displays" but calling them "retina displays" seems disingenuous.
Yeah, just not according to actual doctors and optical specialists. But what do they know?
Edit: For those downvoting this I should have probably provided supporting evidence, though oddly no one treated the parent post in the same way. Feel free to follow the references at the base of this article: http://clarkvision.com/imagedetail/eye-resolution.html
Maybe because they were ALREADY familiar with numerous articles examining the matter.
>Feel free to follow the references at the base of this article: http://clarkvision.com/imagedetail/eye-resolution.html*
It's funny how you send as "supporting evidence" non-specific to the subject matter studies, that just talk about the eye and it's capabilities, while never testing the actual "retina display" math and numbers. It's like you point us to some huge volume of "Ophthalmology" and say "I'm right and here's the proof".
Here's some more topic-specific exhibits:
We don't care about the resolving power of the retina for some bizarro "Heroes" type people with super-sight, or in the abstract. We care that we can't distinguish individual pixels or nearly can't distinguish them. Which is the case.
That "large part of the population"? Actually minuscule.
>Surely you're not going to suggest there are serious scientific sources that focus specifically on Apple screens? I thought actual research was what you made your initial comment about.
I didn't suggest such at the first place. What I wrote was that "actual doctors and optical specialists" agree that the claims are accurate. Plus, you don't need "actual research on Apple screens". If you know their DPI and the viewing distance, you can work it out from general research on the eye, and it will hold true for any other manufacturer too.
So, here's another actual expert (noticed the Ph.D and vision scientist parts?):
According to William H.A. Beaudot, Ph.D., a vision scientist who was a research associate at McGill University in Montreal and founder of KyberVision. “In my opinion, Apple’s claim is not just marketing, it is actually quite accurate based on a 20/20 visual acuity,” said Beaudot.
(...) Dr. Soneira also claims in the Wired article that the term Retina Display is more of a marketing term and is “superamplified imaginary nonsense.” Beaudot doesn’t agree. “Since this display is able to provide a visual input to the retina with a spatial frequency up to 50 cycles per degree when viewed from a distance of 18-inches, it almost matches the retina resolution according to the Nyquist-Shannon sampling theorem,” said Beaudot. “As such, Apple new display device can be called without dispute a Retina Display. Could it get better? Sure, but so far this is the closest thing ever done in display technology for the consumer market that matches the human retina resolution.”
Plus, as a tech geek, shouldn't you be jumping with joy that we have achieved widespread adoption of such high DPI screens, instead of arguing for minor details on their naming, and if they match the retina perfectly or just 20/20 vision etc?
I don't know why the expert you're quoting is specifying an 18 inch viewing distance when the article you appear to have quoted from was speaking of the iPhone 4; Apple claims a 12 inch viewing distance here as far as I'm aware. Then he makes some vague statement about it being possible to do better and this is simply the closest we've gotten to a retina resolution so far. Sometimes academics just want a bit of press time because it makes them look good.
Anyway, it's great we're getting increasing DPI on our devices, I'm just a bit afraid we'll get stuck and not progress to true retina displays because the consumers will be convinced they already have it anyway.