# interesting ideas --- interesting ideas

• To: math-font-discuss@cogs.susx.ac.uk
• Subject: interesting ideas --- interesting ideas
• From: Justin Ziegler <ziegler@goofy.zdv.uni-mainz.de>
• Date: Fri, 06 Aug 1993 09:06:10 -0000

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Date: 04 Aug 1993 15:48:32 -0400 (EDT)
>From: Michael Downes <MJD@MATH.AMS.ORG>
Subject: Re:  The skewchar.
To: ziegler@micky.zdv.Uni-Mainz.DE

<<
<<<
since the kerns for the
skewchar have to be built into the font, the character number of the
skewchar itself should be available as a fontdimen.
>>>

That is a nice idea, but has one problem. When using scaled fonts, the
skewchar would get scaled as well. I don't think that we want that.
>>

OK, good point. How about two fontdimens x and y, such that the ratio
x/y gives the needed character number. Interesting also, that TeX does
not scale \fontdimen 1. Thus another approach for math fonts might be
to use fontdimen1 to give the value of \skewchar, and use the ratio
height/width of skewchar to give the slant per point. This is assuming
that the font position \skewchar does not contain a real character
intended for typesetting---which is a good idea anyway.

But actually, it occurs to me now, a better approach is to mandate
always \skewchar = 0 for math fonts and leave font position 0 empty.
This solves the problem of having to find a suitable character for
\skewchar that will never naturally occur in combination with the
characters for which skews are specified. If there is other extra
information needed for a math font, it could be encoded in the height,
width, depth of character 0.

One might even envision the following extension: suppose S = skewchar,
X = other character. The pair kern for XS would give the amount by
which a top accent should be shifted right, in order to be centered above
the apex of the character X. The pair kern for SX would give the
amount by which a bottom accent should be shifted left, in order to be
centered below the character X.

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