RE: Type1 fonts

[Jeff Henrikson]

> The problem is determining the outline of a
> stroked, self-overlapping drawing. That involves some nasty
> mathematics. And the feta font definitely uses penstrokes and overlaps.

Arg.  I was thinking that stroking was not heavily utilized.  Didn't look close 
enough.  My bad.

> Have you actually read the MetaFog paper by Richard Kinch? Parsing the

I have now.  I get that the envelope computation is a bit involved.  I remember 
trying to solve this for fun once before for the
case of a circle stroke along a bezier path and then getting bored (ie, 
stumped) before I found an answer.  But it isn't obvious to
me why the "Weeding" thing is so hard so as to be entirely computed by user GUI 
interaction.  It seems like a straightforward
application of the beginnings of algebraic topology.  CorelDraw is certainly 
able to take unions, intersetions, and differences of
big messes of outlined shapes without problems.  Mysterious.  And the one 
sentence discussion "Manual input to the conversion
process is vital, because METAFONT output often has degenerate shapes and 
intersections that defy an automatic solution." doesn't
seem to help.

At least I now have an explanation for why stroke to outline conversion is not 
a standard feature of high end outline editors such
as CorelDraw and Adobe Illustrator.  I have always wondered this.


Jeff Henrikson


> -----Original Message-----
> From: address@hidden
> [mailto:address@hidden Behalf Of Han-Wen Nienhuys
> Sent: Wednesday, July 11, 2001 5:02 PM
> To: Jeff Henrikson
> Cc: gnu-music-discuss
> Subject: FW: Type1 fonts
>
>
> address@hidden writes:
> > > The problem is
> > > rather difficult, btw.
> >
> > The general problem is, of course, but have you bothered to read the
> > feta type 3 code?  There's nothing sophisticated in it and I'm sure
> > an experienced postscript hacker could cook up (at most) a simple
> > recursive decent parser to do it, maybe with a little duct tape.
>
> Have you actually read the MetaFog paper by Richard Kinch? Parsing the
> file is not the problem. The problem is determining the outline of a
> stroked, self-overlapping drawing. That involves some nasty
> mathematics. And the feta font definitely uses penstrokes and overlaps.
>
> > BTW- I was wondering the other day how much nonlinear scaling
> > behavior there is in feta.  (Ie, the thing that Computer Modern does
> > a lot but TrueType, Type 1, fonts can't.)  I don't know enough
> > metafont to see for myself.
>
> there is not much, but I'd like to expand in that direction: we have a
> blot-diameter, that should cause the smaller glyphs to be a little
> chubbier. It is not used by many glyphs, though.
>
>
> --
> Han-Wen Nienhuys   |   address@hidden    | http://www.cs.uu.nl/~hanwen/
>
>
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