[metapost] MetaPost 1.770 (test release)

Taco Hoekwater taco at elvenkind.com
Mon Dec 10 11:20:08 CET 2012

We are happy to announce a new test release of MetaPost:

MetaPost 1.770

This is a test release for the new functionality planned in MetaPost 1.800.

This version will not be uploaded to CTAN / TLcontrib yet. The plan is
to wait for a few weeks before releasing 1.800. That will then be an
official end-user release.

Bugs in the current version are expected, so use with care!

The standalone distribution package and a win32 binary can be downloaded
immediately from


What is new in MetaPost version 1.770:

Fixes & improvements:

* There is a new bitmap backend:


   This backend uses cairo and libpng to generate PNG bitmap data.

   Associated with this, there are new internals "hppp" and "vppp",
   that are used by the bitmap backend to decide on the scale of
   the generated bitmap. Default value for both new internals is
   "1.0", i.e. one pixel per Metapost point.

* On the command line, adding


   switches to double precision floating point internal numerical values
   instead of the traditional scaled point. There is also an identically
   named new read-only internal to query the current setting. The
   possible return values for that are currently "scaled" and "double".

   With "double" in effect, numerical values can be expressed in
   scientific notation including exponent, e.g.:

      a = 23.5E71;

   and the warning limit (traditionally 4096.0) has been extended to
   allow for the greater range.

* The C API has been extended to allow path control point resolution
    without going through the Metapost input language, see
    manual/mplibapi.tex for details.

* The C API has been extended with a "math_mode" switch in the options
   structure, and the memory size options as well as "ini_mode" have
   been removed (the MPlib instance now always starts up in inimp mode)

* The code for picture shipout now uses "double" for all floating point
   values. This can give small differences in the actual output files in
   traditional mode due to the required scaled -> double conversion, but
   was necessary to support the new numerical backend code.

* The Lua API internals have been updated to reflect the C API changes.

* All known crashes in earlier versions of Metapost have been fixed.

Known issues:

* The manual is not up-to-date yet on the metapost input language

* There are various small memory leaks (for the most part, these were
   already present in mpost 1.50x series).

Legal notice / license / bug reports

MetaPost is a system for producing graphics developed by John Hobby
at AT&T, based on Donald Knuth's Metafont.  The MetaPost home page
is http://tug.org/metapost.

MetaPost is free software: you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation, either version 2.1 of the License, or
(at your option) any later version.

The MetaPost development project is currently hosted at Supelec,
http://foundry.supelec.fr/gf/project/metapost; with a bug tracker
at http://tracker.luatex.org/. Please report bugs and
request enhancements through there if possible. Alternatively, you
can reach us through the <metapost at tug.org> mailing list as well.

Have fun!

Taco Hoekwater, for the MetaPost team, December 10, 2012.

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