Re: Checksums (was re: 8r fonts)

["Berthold K.P. Horn" <bkph@ai.mit.edu>]

   Piet Tutelaers writes:
    > > (1) what happens if WX is non-integer (as it is in all CM, AMS etc fonts
    > >   --- or at least if it isn't fractional then you do not have good
    > >   fonts!)?

    > Non-integers are currently *not* supported. They were not foreseen by Tom
    > Rokicki. Perhaps Berthold wants to learn us why we need them "uberhaupt?

Because some fonts (such as most of Knuth's fonts) do not have integer
advance widths when expressed in 1/1000-th of an em.  And those CM
fonts out there that round advance widths off, well they just are
approximations, not the real thing!

For example, in some CM fonts, Knuth worked mostly in multiples of
1/36 th of a point.

   Fontinst supports them, but only by brute force truncation after the
   decimal point.  They were introduced by Adobe at the same time as MM
   fonts, and I suspect that that's not a coincidence!  MM AFMs are
   generated by interpolating, so it's not surprising you need
   non-integer AFM values.

That is not quote correct, I think. The CM fonts had AFM files with
fractional widths ever since they first came out somewhere between
1988 and 1990.  True, some software choked on those numbers, but then
there is always software around that makes unwarranted assumptions.

   Alan.