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# $Id: gp_unix.py,v 2.3 2001/01/07 21:35:13 mhagger Exp $
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# Copyright (C) 1998,1999 Michael Haggerty <mhagger@alum.mit.edu>
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version. This program is distributed in
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# the hope that it will be useful, but WITHOUT ANY WARRANTY; without
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# even the implied warranty of MERCHANTABILITY or FITNESS FOR A
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# PARTICULAR PURPOSE. See the GNU General Public License for more
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# details; it is available at <http://www.fsf.org/copyleft/gpl.html>,
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# or by writing to the Free Software Foundation, Inc., 59 Temple Place
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# - Suite 330, Boston, MA 02111-1307, USA.
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"""gp_unix -- an interface to gnuplot used for unix platforms.
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This file implements a low-level interface to a gnuplot program for a
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unix platform (actually it is used for any non-Windows, non-Mac
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system). This file should be imported through gp.py, which in turn
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should be imported via 'import Gnuplot' rather than these low-level
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__cvs_version__ = '$Revision: 2.3 $'
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# ############ Configuration variables: ################################
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"""The configuration options for gnuplot on generic platforms.
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Store the options in a class to make them easy to import and
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modify en masse. If you want to modify the options from the
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command line or within a running program, do something like the
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Gnuplot.GnuplotOpts.gnuplot_command = '/bin/mygnuplot'
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# Command to start up the gnuplot program. If your version of
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# gnuplot is run otherwise, specify the correct command here. You
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# could also specify a full path or append command-line options
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gnuplot_command = 'gnuplot'
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# Recent versions of gnuplot (at least for Xwindows) allow a
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# `-persist' command-line option when starting up gnuplot. When
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# this option is specified, graph windows remain on the screen
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# even after you quit gnuplot (type `q' in the window to close
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# it). This can be handy but unfortunately it is not supported by
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# older versions of gnuplot. The following configuration variable
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# specifies whether the user's version of gnuplot recognizes this
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# option or not. You can set this variable to 1 (supports
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# -persist) or 0 (doesn't support) yourself; if you leave it with
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# the value None then the first time you create a Gnuplot object
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# it will try to detect automatically whether your version accepts
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recognizes_persist = None # test automatically on first use
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# What should be the default if the persist option is not
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# specified explicitly?
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# Recent versions of gnuplot allow you to specify a `binary'
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# option to the splot command for grid data, which means that the
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# data file is to be read in binary format. This option saves
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# substantial time writing and reading the file, and can also save
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# substantial disk space and therefore it is the default for that
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# type of plot. But if you have an older version of gnuplot (or
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# you prefer text format) you can disable the binary option in
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# either of two ways: (a) set the following variable to 0; or (b)
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# pass `binary=0' to the GridData constructor. (Note that the
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# demo uses binary=0 to maximize portability.)
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recognizes_binary_splot = 1
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# Data can be passed to gnuplot through a temporary file or as
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# inline data (i.e., the filename is set to '-' and the data is
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# entered into the gnuplot interpreter followed by 'e'). If
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# prefer_inline_data is true, then use the inline method as
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# default whenever it is supported. This should be fast but will
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# use more memory since currently the inline data is put into a
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# big string when the PlotItem is created.
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prefer_inline_data = 0
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# After a hardcopy is produced, we have to set the terminal type
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# back to `on screen' using gnuplot's `set terminal' command. The
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# following is the usual setting for Xwindows. If it is wrong,
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# change the following line to select the terminal type you prefer
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# to use for on-screen work.
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# Gnuplot can plot to a printer by using "set output '| ...'"
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# where ... is the name of a program that sends its stdin to a
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# printer, or by "set output 'printer_device', where
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# 'printer_device is the name of a file-like interface to the
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# printer. On my machine the appropriate program is `lpr', as set
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# below. On your computer it may be something different (like
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# `lp'); you can set that by changing the variable below. You can
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# also add options to the print command if needed.
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default_lpr = '| lpr'
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# Enhanced postscript is an option to the postscript terminal
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# driver that requests enhanced treatment of strings (for example,
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# font changes, superscripts, and subscripts). Set to 1 to enable
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# or 0 to disable. If you have a version of gnuplot earlier than
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# 3.7, you should set this to None (*not* 0!) so that the option
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# is not used at all.
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prefer_enhanced_postscript = 1
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# ############ End of configuration options ############################
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"""Determine whether gnuplot recognizes the option '-persist'.
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If the configuration variable 'recognizes_persist' is set (i.e.,
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to something other than 'None'), return that value. Otherwise,
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try to determine whether the installed version of gnuplot
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recognizes the -persist option. (If it doesn't, it should emit an
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error message with '-persist' in the first line.) Then set
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'recognizes_persist' accordingly for future reference.
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if GnuplotOpts.recognizes_persist is None:
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g = popen('echo | %s -persist 2>&1' % GnuplotOpts.gnuplot_command, 'r')
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response = g.readlines()
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GnuplotOpts.recognizes_persist = (
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(not response) or (string.find(response[0], '-persist') == -1))
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return GnuplotOpts.recognizes_persist
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class GnuplotProcess:
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"""Unsophisticated interface to a running gnuplot program.
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This represents a running gnuplot program and the means to
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communicate with it at a primitive level (i.e., pass it commands
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or data). When the object is destroyed, the gnuplot program exits
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(unless the 'persist' option was set). The communication is
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one-way; gnuplot's text output just goes to stdout with no attempt
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to check it for error messages.
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'gnuplot' -- the pipe to the gnuplot command.
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'__init__' -- start up the program.
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'__call__' -- pass an arbitrary string to the gnuplot program,
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followed by a newline.
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'write' -- pass an arbitrary string to the gnuplot program.
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'flush' -- cause pending output to be written immediately.
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def __init__(self, persist=None):
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"""Start a gnuplot process.
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Create a 'GnuplotProcess' object. This starts a gnuplot
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program and prepares to write commands to it.
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'persist=1' -- start gnuplot with the '-persist' option,
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(which leaves the plot window on the screen even after
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the gnuplot program ends, and creates a new plot window
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each time the terminal type is set to 'x11'). This
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option is not available on older versions of gnuplot.
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persist = GnuplotOpts.prefer_persist
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if not test_persist():
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raise ('-persist does not seem to be supported '
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'by your version of gnuplot!')
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self.gnuplot = popen('%s -persist' % GnuplotOpts.gnuplot_command,
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self.gnuplot = popen(GnuplotOpts.gnuplot_command, 'w')
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# forward write and flush methods:
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self.write = self.gnuplot.write
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self.flush = self.gnuplot.flush
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def __call__(self, s):
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"""Send a command string to gnuplot, followed by newline."""
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build/lib/Gnuplot/gp_unix.py
