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Re: Intrinsic size of jpeg images

From: Ian Hickson <ian@hixie.ch>
Date: Fri, 28 Jan 2005 15:42:51 +0000 (UTC)
To: leslie.brown@evidian.com
Cc: www-style@w3.org
Message-ID: <Pine.LNX.4.61.0501281540190.11312@dhalsim.dreamhost.com>

On Fri, 28 Jan 2005 leslie.brown@evidian.com wrote:
> On the other hand, I'd expect a web browser to ignore the "300dpi" and 
> render the image at 600x900 pixels in the absence of any width and 
> height definitions in CSS or HTML.

600x900 CSS pixels, or display pixels? (Note that there is not a 
one-to-one mapping from CSS pixels to display pixels, CSS pixels are 
actually an angular unit.)

Why would you expect something to print at the specified absolute size, 
but display on a screen at a different size?

> To take the idea to its logical extreme, if the "correct" approach is to 
> treat the dpi resolution as gospel, then videoprojectors would have to 
> incorporate a rangefinder so that they could measure the distance to the 
> screen, calculate the total image size, and tell the PC driving them to 
> scale the jpeg image accordingly...

Yes. This is actually required by CSS for font sizes and margins set in 
pixels, for instance. Not that anyone yet supports this.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Friday, 28 January 2005 15:42:54 UTC

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