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Re: [css3-values] Physical length units

From: Linss, Peter <peter.linss@hp.com>
Date: Wed, 22 Feb 2012 18:57:57 -0800
Cc: "www-style@w3.org" <www-style@w3.org>
Message-Id: <2C50D023-A57E-4A6F-8497-1691E1F923A2@hp.com>
To: Felix Miata <mrmazda@earthlink.net>
On Feb 22, 2012, at 5:44 PM, Felix Miata wrote:

> On 2012/02/23 00:54 (GMT) Linss, Peter composed:
> 
> 2) CSS has physical length units, and always has. They're called 'in',
>> 'cm', 'pt' and the like.
> 
> Those are unfortunate misnomers as long as they are presumptively logical 
> rather than physical as dictated by the 96px=1in specification.

This sentence demonstrates the fundamental disconnect here. 'in' _is_ a physical unit. The difference now is that 'px' is a physical unit too, it's defined as 1/96th of an inch and therefore is physical, not logical. It has the same worth as a 'pt', it's just a convenient fraction of an inch. Whether _all_ units get rendered physically (i.e. matched to real-world measurements), or logically (i.e. scaled to some factor, most commonly to obtain device pixel ratios that give good results), is a UA rendering time decision.

What you don't have are device units, i.e. 1 device pixel. And frankly you never really did, it just happened to work out that way in many cases on screen only. The way screen resolutions are climbing these days, and the preponderance of devices where zooming is commonplace, having an actual device pixel unit is all but useless.

Regardless, this thread is closed. If you have something new to discuss (and I really mean new, all this so far has already been beaten to death) then start a new thread with a new subject.
Received on Thursday, 23 February 2012 02:58:21 GMT

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