Path: utzoo!mnetor!uunet!husc6!bbn!rochester!ken
From: ken@cs.rochester.edu (Ken Yap)
Newsgroups: comp.fonts
Subject: Re: Standard font formats.
Message-ID: <8421@sol.ARPA>
Date: 8 Apr 88 05:41:44 GMT
References: <5352@pyr.gatech.EDU>
Reply-To: ken@cs.rochester.edu (Ken Yap)
Organization: U of Rochester, CS Dept, Rochester, NY
Lines: 31

|My personal opinion about standard font formats is that they shouldn't
|use a bitmap representation.  Bitmaps are tied to a particular device
|resolution and are difficult to scale properly to other resolutions.

Most high resolution fonts are stored as outlines. Storing them as
bitmaps would require too much space anyway.

The problem with storing low resolution fonts as outlines is
quantization error. If the font is to look decent, some manual tuning
may be necessary. In that case you have added information that can't be
recovered by rasterizing the outline.

The Hershey fonts aren't that great on paper if you look closely. You
can see the articulation points.  I once tried generating METAFONT from
the Hershey fonts and did persuade METAFONT to smooth the edges.
Unfortunately some manual editing is required to tell METAFONT where
paths begin and end.  In the Hershey data, unrelated curves are stored
in sequence because the plotter pen doesn't care. But these have to be
broken up for METAFONT or the spline routines go wild. Too much work so
I shelved that idea. If you want to give it a shot, you're welcome to
my code.

PostScript seems to be quite successful at automatic smoothing at low
resolution, I wonder how they do it. It's all hidden in their firmware,
no doubt.

Incidentally, it is straightforward in principle (if not in practice)
to generate outline fonts with METAFONT.  Simply ask for an adequately
high resolution, then convert the rasters to outlines.

	Ken