Re: Widths in tables

Mon, 24 Apr 95 15:43:28 EDT

[Bert Bos:]

> Dave Ragget writes:

[stuff omitted]

> |The use of ems is problematic in this case as an em isn't the same
> |as the width of a character for a fixed pitch font. My understanding
> |is that the em is equal to the point size which is related to the
> |height of the font - not its width.
> That is not the way I heard it. em is a unit of width, not of height
> (ex and others are for height). It is a measure associated with a font
> by the designer and it is traditionally about the width of an M (hence
> the name). An en is exaclty half an em.

Dave is correct. An em is the body height of the font. If the font
is a 12 point font, then the body height is 12 points (that's what "12
point font" means) and the value of an em is 12 points. In *most*
traditional latin fonts, the lower case and capital "m" characters (I
mean the physical pieces of metal) are exactly as wide as they are
tall, making the type itself square in cross section; that's why ems
are often called "em quads".


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