[matplotlib-devel] Subsetting fonts in Postscript

[Michael D. <md...@st...>]

[I've been discussing this off-list with John Hunter, and I thought I'd 
summarize that conversation in case anyone else on this list has any 
thoughts or suggestions.]

I've started working on the problem of reducing Postscript output file 
sizes by saving out only the glyphs that are used in the figure.  There 
are (at least) two alternative approaches:

1. Subset the Truetype font into another Truetype font and embed it as 
we do now.  This could theoretically be done with fonttools/ttx.  
Writing out .ttf files looks to be rather complex, and there's a lot of 
griping about the format itself to be found on the 'net.  John also 
mentioned that he'd prefer not to add the requirement of fonttools to 
the mix from past experience.

2. Convert the Truetype font to a Type 3 font (which is basically a set 
of standard Postscript commands).  There is a small C application 
(http://www.this.net/~frank/ttconv.tar.gz) that converts TTF to Type 3 
that looks to work quite well.  Some modifications would have to be made 
to actually subset the font and to integrate with Python etc., but it's 
fairly straightforward code, and the licensing is amenable to including 
it in the matplotlib source tree.

Clearly, I'm leaning toward option #2, but thought I'd open it to the 
crowd to see if there are any other options or opinions on the matter.

The plan is to make the choice of the existing or new behavior be an 
option, with the default TBD.

Cheers,
Mike