Re: [Matplotlib-users] TeX in xlabel ?

[John H. <jdh...@ac...>]

>>>>> "Chris" == Chris Barker <Chr...@no...> writes:

    Chris> Gary wrote:
    >> Matplotlib doesn't support \text, and it requires that the
    >> first and last characters of a TeX string be $.  I guess it
    >> only processes mathmode.  Well, it can't do *everything*.

It is on the goals page (http://matplotlib.sourceforge.net/goals.html)
to support embedded math strings like

  s = r'Mean ($\mu=5) and standard deviation ($\sigma=1$)'

This wouldn't be too hard - just takes some time that I haven't had of
late.

    Chris> Oh well, I've always thought that if you want to support
    Chris> Math in a graphics package, you would actually use TeX,
    Chris> rather than emulating it. Maybe like PyX:

    Chris> http://pyx.sourceforge.net/

Yes, but you lose the platform independence and portability by doing
this.  It would be nice to be able to choose one or the other -- see
below.

    Chris> The problem, of course, is that requiring a TeX system is a
    Chris> BIG dependency! It would be nice if one could re-package
    Chris> the Tex interpreter to be embedded. I have no idea how big
    Chris> a job that would be. You'd also have all the font issues,
    Chris> of course, but while that would all be a lot of work, I'm
    Chris> not sure it would be more work than trying to re-write TeX!

It would be a monster job.  There is basically no way to factor tex
into components -- it's a monolithic system, in part because of the
heavy use of web macros.  And web2c, the conversion of web/pascal to
c, is GPLd and less permissive than the matplotlib license.  So
embedding tex is a no-go, aside from size considerations.  But there
are some possibilities for improving what matplotlib already offers.

One is to fall back on tex where available as a command line tool (as
pyx does, I believe), and use other command line tools to convert the
dvi to png or some other raster format and then embed it.  This would
require a few external libs and utilities, but it's certainly doable.

Another idea I had while reading Knuth's "TeX: The Program" is to use
the layout information in the TFM font metric files.  Apparently math
fonts have additional layout information in them, like where to place
superscripts.  I've looked at several tfm parsing implementations, and
haven't found one yet that actually extracts this information; most
extract the standard font information but not the special math
information.  But if we could access this info, we could include the
tfm files for common raster sizes and use the layout info crafted by
the master himself.

A third possibility would be to support mathml, using some good mathml
renderer.  Is there a good, free mathml rendering library - what does
mozilla use for this?

JDH