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Re: [CSS21] 4.3.2 Lengths (reference pixel?)

From: Brad Kemper <brad.kemper@gmail.com>
Date: Sun, 12 Dec 2010 08:17:20 -0800
Cc: www-style@w3.org
Message-Id: <AAA6D1B3-76CD-4EE4-A948-4F3CA61A374E@gmail.com>
To: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>

On Dec 12, 2010, at 5:05 AM, Dr. Olaf Hoffmann wrote:

>> The point you seem to be missing is that we are not trying to define inches
>> and centimeters. We are defining the CSS units of 'in' and 'cm'. In some
>> contexts, these have a direct relationship to inches and centimeters, and
>> in others they do not. On projector screens, for instance, 'in' is just
>> about as divorced in meaning from a physical "inch" as it is from the
>> preposition "in".
> 
> No, as cited several times, it is written in the draft:
> 
> "
> cm: centimeters
> mm: millimeters
> "
> This means, that 'cm' represents centimeters and 
> 'mm' represents millimeters. These are the same
> letters (symbols) and words as commonly used for international
> standard length units called 'centimeter' and 'millimeter'.

So, would it be less objectionable to you if we had:

in: CSS inches*
cm:  CSS centimeters*
mm: CSS millimeters*
[ etc. ]
*See discussion below for times when the CSS units are not equal to the corresponding metric or traditional units.

In theory, you could argue that it would have been better to use abbreviations that did not so closely match the metric abreviations, e.g.:

cssin: CSS inches*
csscm:  CSS centimeters*
cssmm: CSS millimeters*
[ etc. ]

However, as Anton pointed out, this doesn't serve any practical purpose. It just makes the units harder to learn and use, and at this point cannot be changed retroactively because the old CSS units are already in widespread use and need practical meanings in all output devices. The CSSWG considered it more important to have consistency of converting between the various CSS units than it did it creating definitions that could not be reliably adhered to.
 
Received on Sunday, 12 December 2010 16:17:55 GMT

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