(maxima.info)Introduction to Plotting

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12.1 Introduction to Plotting
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Maxima uses an external plotting package to make the plots (see the
section on 'Plotting Formats').  The plotting functions calculate a set
of points and pass them to the plotting package together with a set of
commands.  That information can be passed to the external program either
through a pipe or by calling the program with the name of a file where
the data has been saved.  The data file is given the name
'maxout_xxx.format', where 'xxx' is a number that is unique to every
concurrently-running instance of Maxima and 'format' is the name of the
plotting format being used ('gnuplot', 'xmaxima', 'mgnuplot',
'gnuplot_pipes' or 'geomview').

   There are to save the plot in a graphic format file.  In those cases,
the file 'maxout_xxx.format' created by Maxima includes commands that
will make the external plotting program save the result in a graphic
file.  The default name for that graphic file is 'maxplot.extension',
where 'extension' is the extension normally used for the kind of graphic
file selected.

   The 'maxout_xxx.format' and 'maxplot.extension' files are created in
the directory specified by the system variable 'maxima_tempdir'.  That
location can be changed by assigning to that variable (or to the
environment variable MAXIMA_TEMPDIR) a string that represents a valid
directory where Maxima can create new files.  The output of the Maxima
plotting command will be a list with the names of the file(s) created,
including their complete path.

   If the format used is either 'gnuplot' or 'xmaxima', the external
programs 'gnuplot' or 'xmaxima' can be run, giving it the file
'maxout_xxx.format' as argument, in order to view again a plot
previously created in Maxima.  Thus, when a Maxima plotting command
fails, the format can be set to 'gnuplot' or 'xmaxima' and the
plain-text file 'maxout_xxx.gnuplot' (or 'maxout_xxx.xmaxima') can be
inspected to look for the source of the problem.

   The additional package Note: draw provides functions similar to the
ones described in this section with some extra features.  Note that some
plotting options have the same name in both plotting packages, but their
syntax and behavior is different.  To view the documentation for a
graphic option 'opt', type '?? opt' in order to choose the information
for either of those two packages.