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Re: What's an em

From: Erik van der Poel <erik@netscape.com>
Date: Tue, 01 Feb 2000 15:24:34 -0800
Message-ID: <38976B32.AF596635@netscape.com>
To: Just van Rossum <just@letterror.com>
CC: Karlsson Kent - keka <keka@im.se>, www-style@w3.org, "'www-font@w3.org'" <www-font@w3.org>
Just van Rossum wrote:
> 
> You can't measure the *optical* size of any shape by simply looking at it's
> bounding box. Trust me, you're shooting yourself in the foot. Pointsize
> Pointsize Pointsize. It's the only thing that means *anything*.

Take a look at the first image in the definition of font-size-adjust in
the CSS2 spec:

http://www.w3.org/TR/REC-CSS2/fonts.html#propdef-font-size-adjust

It shows a number of different fonts, all rasterized at the same
"Pointsize", as you call it. The "subjective apparent size" depends on
the x-height (mostly). Is the "optical size" (as you call it) the same
as the "subjective apparent size"?

If so, the "Pointsize" isn't the only thing that means anything. CSS2
claims that the ex/em ratio is important.

Not true?

Erik
Received on Tuesday, 1 February 2000 18:28:13 GMT

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