[pdftex] Patch for pdftex for subsetted font printing problem

Tom Kacvinsky tjk at ams.org
Mon Jun 18 16:54:47 CEST 2001

pdftex does not handle the case of:

   450 10 div callsubr

You know, you could look at the code for pdftex.  It is freely available to
look at, unlike the code for DVIPSONE. ;-)

On that note, I have to ask: how does DVIPSONE get around this?  Does it
fully interpret the charstirng commands?  Did you know that rand is a
supported Type 1 charstring command?  How do you handle that, especially
when renumbering charstrings.

I am taking my cue from the email we (Thanh, you, and I) received this
weekend from Adobe...


On Mon, 18 Jun 2001, Y&Y Support wrote:

> At 08:15 2001-06-18 -0400, Tom Kacvinsky wrote:
> >Hi Hans,
> >
> > >
> > > > subsetted font. To do that, one needs to renumber all of the subroutines,
> > > > and make sure the charstrings which call these renumbered subroutines use
> > > > the new numbers, etc...
> > >
> > > sounds like a good patch
> > >
> >
> >But difficult.  pdftex already disassembles charstrings and subroutines
> >to figure out which subroutines are used, but it does not change and then
> >reassemble them.
> I wonder how pdfTeX handles e.g.
> 450 10 div callsubr
> :-)  This is an unusual, but legal construction.  Extensions of this
> idea (e.g. splitting the computation over different Subrs, possibly
> using the stack, possible using OtherSubrs) show that it is quite
> dangerous to think one can figure out what Subrs are used and
> to renumber them...
> Of course, for very many "normal" fonts this works just fine.
> But we have recently seen how dangerous it is to assume
> that because most fonts follow a certain pattern they all must.
> Or because the majority of PS interpreters or font rasterizers
> do something they all must...
> http://www.yandy.com/acrobat5.htm
> --
> Y&Y Support mailto:support at YandY.com http://www.YandY.com/unique.htm (PG)

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