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Re: em

From: Erik van der Poel <erik@netscape.com>
Date: Mon, 19 Jun 2000 10:51:59 -0700
Message-ID: <394E5DBF.8FAAFA4@netscape.com>
To: Sebastien J Duval <SJDuval@rbrooks.com>
CC: www-style <www-style@w3.org>
Sebastien J Duval wrote:
> 
> em defines the width of the letter M for the font.

No. As far as I can tell, the consensus in the CSS community is that
"em" refers to the font's design size. For example, in TrueType fonts,
there is a field called unitsPerEm, and the glyphs are specified in
terms of coordinates in that space. The designer does not have to make
the em square be as wide as the letter M. The glyphs can protrude
outside the em square.

On the other hand, TeX appears to define "em" in terms of the letter M
or m. So TeX and CSS appear to be different in this area.

Erik
Received on Monday, 19 June 2000 13:53:11 GMT

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