# $Id: gp_macosx.py 291 2006-03-03 08:58:48Z mhagger $
# Copyright (C) 1998-2003 Michael Haggerty <mhagger@alum.mit.edu>
#
# This file is licensed under the GNU Lesser General Public License
# (LGPL). See LICENSE.txt for details.
"""gp_macosx -- an interface to the command line version of gnuplot
used under Mac OS X.
The only difference between this interface and gp_unix is that
default_term is 'aqua'.
This file implements a low-level interface to gnuplot. This file
should be imported through gp.py, which in turn should be imported via
'import Gnuplot' rather than using these low-level interfaces
directly.
"""
# ############ Configuration variables: ################################
class GnuplotOpts:
"""The configuration options for gnuplot on Mac OS X.
See the gp_unix.py for documentation on all of the parameters.
"""
gnuplot_command = 'gnuplot'
recognizes_persist = None # test automatically on first use
prefer_persist = 0
recognizes_binary_splot = 1
prefer_inline_data = 0
# os.mkfifo should be supported on Mac OS X. Let me know if I'm
# wrong.
support_fifo = 1
prefer_fifo_data = 1
default_term = 'aqua'
default_lpr = '| lpr'
prefer_enhanced_postscript = 1
# ############ End of configuration options ############################
from os import popen
def test_persist():
"""Determine whether gnuplot recognizes the option '-persist'.
If the configuration variable 'recognizes_persist' is set (i.e.,
to something other than 'None'), return that value. Otherwise,
try to determine whether the installed version of gnuplot
recognizes the -persist option. (If it doesn't, it should emit an
error message with '-persist' in the first line.) Then set
'recognizes_persist' accordingly for future reference.
"""
if GnuplotOpts.recognizes_persist is None:
import string
g = popen('echo | %s -persist 2>&1' % GnuplotOpts.gnuplot_command, 'r')
response = g.readlines()
g.close()
GnuplotOpts.recognizes_persist = (
(not response) or (string.find(response[0], '-persist') == -1))
return GnuplotOpts.recognizes_persist
class GnuplotProcess:
"""Unsophisticated interface to a running gnuplot program.
This represents a running gnuplot program and the means to
communicate with it at a primitive level (i.e., pass it commands
or data). When the object is destroyed, the gnuplot program exits
(unless the 'persist' option was set). The communication is
one-way; gnuplot's text output just goes to stdout with no attempt
to check it for error messages.
Members:
'gnuplot' -- the pipe to the gnuplot command.
Methods:
'__init__' -- start up the program.
'__call__' -- pass an arbitrary string to the gnuplot program,
followed by a newline.
'write' -- pass an arbitrary string to the gnuplot program.
'flush' -- cause pending output to be written immediately.
'close' -- close the connection to gnuplot.
"""
def __init__(self, persist=None):
"""Start a gnuplot process.
Create a 'GnuplotProcess' object. This starts a gnuplot
program and prepares to write commands to it.
Keyword arguments:
'persist=1' -- start gnuplot with the '-persist' option,
(which leaves the plot window on the screen even after
the gnuplot program ends, and creates a new plot window
each time the terminal type is set to 'x11'). This
option is not available on older versions of gnuplot.
"""
if persist is None:
persist = GnuplotOpts.prefer_persist
if persist:
if not test_persist():
raise ('-persist does not seem to be supported '
'by your version of gnuplot!')
self.gnuplot = popen('%s -persist' % GnuplotOpts.gnuplot_command,
'w')
else:
self.gnuplot = popen(GnuplotOpts.gnuplot_command, 'w')
# forward write and flush methods:
self.write = self.gnuplot.write
self.flush = self.gnuplot.flush
def close(self):
if self.gnuplot is not None:
self.gnuplot.close()
self.gnuplot = None
def __del__(self):
self.close()
def __call__(self, s):
"""Send a command string to gnuplot, followed by newline."""
self.write(s + '\n')
self.flush()
|