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From: laporta@apollo.HP.COM (John X. Laporta)
Newsgroups: comp.fonts
Subject: Re: How to define kerning for a soft font?
Message-ID: <4cac478e.20b6d@apollo.HP.COM>
Date: 7 Sep 90 21:48:00 GMT
References: <38743@shemp.CS.UCLA.EDU>
Sender: root@apollo.HP.COM
Reply-To: laporta@apollo.HP.COM (John X. Laporta)
Organization: Hewlett-Packard Company, Apollo Division; Chelmsford, MA
Lines: 35

>What I'm currently thinking of is a program which would construct the
>character shapes for a given font in memory -- then take each pair of
>symbols and try to move them closer together (up to some minimum dis-
>tance, measured in any direction).
>

As far as I know the original kerning was done in Venice by Aldo 
Manutius sometime in the last 1400's. He took his letter forms and
filed off each corner when the counter (flat surface from which
typeform rises) at that corner was spacious.

Then when he set type the characters kerned when the filing angles
fit into one another. That is, `W' and `A' would kern, but `H' and 
`A' would not.

So it sounds like your proposal is in the best typographic tradition,
certainly one of the oldest, and Manutius' work is generally regarded
as very elegant.

By the way, are you aware that there are three types of kerning, and
all three may be enabled simultaneously:

    overall kerning - an identical (positive/negative) amount is
        added to the distance between each pair of characters.
    track kerning - like overall kerning, but the values differ
        for different ranges of point sizes within a given font.
    pairwise/triplet kerning - a lookup table offers kerning
        increments/decrements for specific pairs of characters
        and for the pairs in specific triplets. Kerning triplets
        are often used when the font has no ligatures (e.g. for
        "ffl").

The kerning you are talking about is pairwise decrement.

        John