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Re: Units, font sizing, and zoom suggestion for CSS 3

From: David Perrell <davidp@earthlink.net>
Date: Fri, 21 Jan 2000 11:42:21 -0800
To: www-style <www-style@w3.org>
Message-id: <00da01bf6447$c15cc000$15a8a8c0@davidp>
RE: Units, font sizing, and zoom suggestion for CSS 3Karlsson Kent - keka
wrote:
>>    em - horizontal size of the point size of the font ..."
>The quote continues:
>"about the [horizontal] size of the letter "M" in the current font."
>which apparently wasn't to your liking.

Neither line is particularly likable, but the first refutes one of your
claims. The second does not support it. Both are inaccurate. Em is not
dependent on points, and font glyphs can be so bold and extended and light
and compressed that em is not really "about" M-width at all (unless your
margin for size-similarity exceeds 200%).

Some of your references for em definition contain provable fallacies, e.g.
"...approximately 1000 points (unscaled) in PostScript..." and others are
only historically relevant. In my experience the following best represents
tradition in the printing/typesetting industry during the last few decades:

em
     In composition, a unit of measurement exactly as wide and high as the
     point size being set. So named because the
     letter "M" in early fonts was usually cast on a square body.

The width of M is irrelevant as a standard of measure when you consider (1)
the variation in modern fonts, and (2) alphabets without an M.

David Perrell
Received on Friday, 21 January 2000 14:45:26 GMT

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