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

From: David Singer <singer@apple.com>
Date: Mon, 13 Dec 2010 10:29:27 -0800
Cc: www-style@w3.org
Message-Id: <D80E917B-219F-43A9-8135-A09A0BEB83D9@apple.com>
To: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>
OK, we previously discussed calling these css-cm, css-inch, and so on, since under many circumstances they are cm, inch, etc.;  but that seemed ungainly.

Another possibility would be to insert a paragraph something like:

"CSS physical lengths (e.g. cm, in, pt) are usually, but not always, measured on the display surface.  Under some circumstances it is more appropriate to measure these lengths on a virtual surface.  That virtual surface is at a normal reading distance, and the image on that virtual surface is the presented image (on the actual display, if any) projected onto the virtual surface. These two measurement locations -- the actual display surface, and the virtual surface -- result in the two 'anchor methods'.

(This allows for images on small, high-resolution devices that are intended to be read close-up to display an appropriate quantity of the image, or on large low-resolution devices such as billboards to fill the display appropriately, or for devices without a true display surface, such as projection glasses, nonetheless be consistent with other devices)."

I'm sure there are other possibilities.  But complaining that we don't understand the historical role of the Quai D'Orsay is not leading to them.


David Singer
Multimedia and Software Standards, Apple Inc.
Received on Monday, 13 December 2010 18:30:00 GMT

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