WebKit Limit on Retina JPG Image Display • Hacker News Board

Re: WebKit Limit on Retina JPG Image Display

#21

Post by artursapek » Thu, Mar 22, 2012, 5:17 PM UTC

apinstein wrote: post #5

We ran into this issue while building our HTML5/Mobile Webkit panorama viewer. It took a long time to figure out what was going on, I almost feel that webkit would've been better to just skip the image and log an error to the console, since by resizing your image without your permission typically causes rendering bugs since they literally resize your image down in-line without telling you. We didn't realize it could…

Try switching your PNG's from RGB to Indexed color - depending on what the image is it can dramatically lower the file size.

Re: WebKit Limit on Retina JPG Image Display

#22

Post by wisty » Thu, Mar 22, 2012, 5:32 PM UTC

gokhan wrote: post #18

rorrr wrote: post #13

Earlier quoted context omitted.

You could just slice it into multiple JPGs. It's probably even better for parallel download.

Better? Wrong. Please read "Minimize HTTP Requests" here: http://developer.yahoo.com/performance/rules.html

If you use domain sharding you can get more parellel downloads on older browsers which reduces the problems some due to more requests (parellel request limit on old browsers and unneeded cookies for static resources, but theres still overhead), but that's a separate issue. It's best to avoid the problem altogether by minimizing HTTP Requests (as you suggest).

Re: WebKit Limit on Retina JPG Image Display

#23

Post by brudgers » Thu, Mar 22, 2012, 5:33 PM UTC

apinstein wrote: post #5

We ran into this issue while building our HTML5/Mobile Webkit panorama viewer. It took a long time to figure out what was going on, I almost feel that webkit would've been better to just skip the image and log an error to the console, since by resizing your image without your permission typically causes rendering bugs since they literally resize your image down in-line without telling you. We didn't realize it could…

>"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.

Re: WebKit Limit on Retina JPG Image Display

#24

Post by huxley » Thu, Mar 22, 2012, 5:33 PM UTC

gokhan wrote: post #18

rorrr wrote: post #13

Earlier quoted context omitted.

You could just slice it into multiple JPGs. It's probably even better for parallel download.

Better? Wrong. Please read "Minimize HTTP Requests" here: http://developer.yahoo.com/performance/rules.html

That's a great rule for general purposes, but it's intended for situations where you have lots of small assets that you are asking the client to download.

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.

Re: WebKit Limit on Retina JPG Image Display

#25

Post by huxley » Thu, Mar 22, 2012, 5:46 PM UTC

hetman wrote: post #10

On a mostly unrelated note, I wish blatanly marketing driven terms like "retina display" would stop getting thrown around like this. Thanks to Apple's latest marketing adjustment for the iPad 3, it turns the phone I've owned for over 2 years now actually posesses a "retina display" (N900 for anyone wondering). At the viewing distance specified by Apple, the human retina is in fact capable of discerning a far higher p…

Sigh.

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.

Re: WebKit Limit on Retina JPG Image Display

#26

Post by yonran » Thu, Mar 22, 2012, 5:47 PM UTC

Question: does the HTMLImageElement actually contain fewer pixels, or is it just displayed low-res? Could you take your jpeg, paint it on a canvas using script, and then display it full-resolution?

Re: WebKit Limit on Retina JPG Image Display

#27

Post by brianpan » Thu, Mar 22, 2012, 5:55 PM UTC

eurleif wrote: post #14

brianpan wrote: post #12

Earlier quoted context omitted.

How is he "throwing around" this term? He's specifically talking about the iPad 3. Apple uses this marketing term to signal to the purchaser that they are going to get a certain pixel density. I see retina display, I know I will get a "good looking" display by Apple's standards. If I trust Apple, it means something. That's the purpose of marketing and branding. So what if your phone also has the same pixel density? D…

>BTW, iPhone 4 is a 3.5 inch 640×960 resolution (326 ppi). But the new iPad is 264 PPI.

I included the screen size, because it's a proxy for working distance, and thus pixel density per viewing angle.

http://punchingin.com/chasing-the-6-4-megapixel-unicorn/

http://www.codinghorror.com/blog/2012/03/welcome-to-the-post...

Re: WebKit Limit on Retina JPG Image Display

#28

Post by rorrr » Thu, Mar 22, 2012, 6:11 PM UTC

gokhan wrote: post #18

rorrr wrote: post #13

Earlier quoted context omitted.

You could just slice it into multiple JPGs. It's probably even better for parallel download.

Better? Wrong. Please read "Minimize HTTP Requests" here: http://developer.yahoo.com/performance/rules.html

It's not wrong. If you have only a few slices, they will load in parallel in most browsers.

Re: WebKit Limit on Retina JPG Image Display

#29

Post by batista » Thu, Mar 22, 2012, 6:26 PM UTC

hetman wrote: post #10

On a mostly unrelated note, I wish blatanly marketing driven terms like "retina display" would stop getting thrown around like this. Thanks to Apple's latest marketing adjustment for the iPad 3, it turns the phone I've owned for over 2 years now actually posesses a "retina display" (N900 for anyone wondering). At the viewing distance specified by Apple, the human retina is in fact capable of discerning a far higher p…

At the viewing distance specified by Apple, the human retina is in fact capable of discerning a far higher pixel density anyway.

Yeah, just not according to actual doctors and optical specialists. But what do they know?

Re: WebKit Limit on Retina JPG Image Display

#30

Post by DHowett » Thu, Mar 22, 2012, 6:30 PM UTC

This bug is sort of funny (in the frustrating way) when you're looking for high-resolution wallpapers for the iPad - At least on InterfaceLIFT on-device, you get a 1024x1024 image when trying to fetch the iPad3,x version.