W3C home > Mailing lists > Public > www-style@w3.org > December 1998

Re: platform-specific font size issues

From: Steven Pemberton <Steven.Pemberton@cwi.nl>
Date: Wed, 16 Dec 1998 13:30:53 +0100 (MET)
To: Todd Fahrner <fahrner@pobox.com>
Cc: www-style@w3.org
Message-ID: <13943.42837.152278.435071@schoener.cwi.nl>

 > 2. The 1996 CSS1 standard suggests a 1/90" value for a "reference pixel",
 > extrapolated from a visual angle of 0.0227 degrees visual angle at arms
 > length. UAs are expected to scale pixels appropriately if the physical
 > resolution is known to vary significantly from this value. A 1/90"
 > reference pixel would suggest a rasterization of 12pt into 15px, rather
 > than 16. 15 is of course much closer to 16 than to 12, however. Because no
 > OS/UA currently assumes a 90ppi logical resolution, (nor implements
 > pixel-scaling per CSS1), I think the reference pixel value should be
 > amended to 1/96". It's simple to preserve the suggested 0.0227 degrees
 > visual angle by giving the reference user a longer arm's length. (^:

I've always disagreed with this definition of pixel. It seems to
demand that the browser know how far away the reader is. All of a
sudden if you use a projector, the definition of pixel may change.

A better definition *if you ask me* is: a px unit is 1pt rounded to
the nearest whole number of physical pixels on the device.

Steven Pemberton
Received on Wednesday, 16 December 1998 07:31:00 UTC

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