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Re: Adaptive images

From: Kornel Lesiński <kornel@geekhood.net>
Date: Thu, 02 Jun 2011 12:30:36 +0100
To: public-html@w3.org
Message-ID: <op.vwf4xa2jte2ec8@aimac.local>
On Wed, 01 Jun 2011 11:14:03 +0100, Simon Pieters <simonp@opera.com> wrote:

>> True - but ONLY if the user zooms.  And you don't know ahead of time if  
>> the user will do that :(.
>
> Indeed. However, with the stop early approach you can stop with very low  
> resolution for all images if the user starts in overview view, and then  
> only load more when the user zooms into "normal" zoom view for images  
> that are in view, which I would expect would save more bandwidth  
> compared to author-supplied "normal res" and "high res" dual images.

I don't think stop-early approach is good enough:

- author cannot provide properly anti-aliased subsampled images. While  
this might be OK for photos, it will cause aliased edges and missing thin  
lines in line art.

- HTTP and TCP/IP flow control are not fine-grained enough to stop  
download exactly at the point where desired amount of detail is  
downloaded. Clients may end up getting a lot more or even whole image even  
if they try to stop the download (i.e. even when you close the connection  
immediately, by the time server notices it, the rest of the image may have  
been sent already).

-- 
regards, Kornel Lesiński
Received on Thursday, 2 June 2011 11:31:08 UTC

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