# $Id: gp_win32.py,v 2.9 2001/01/07 21:35:14 mhagger Exp $

# Copyright (C) 1999 Michael Haggerty <mhagger@alum.mit.edu>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.  This program is distributed in
# the hope that it will be useful, but WITHOUT ANY WARRANTY; without
# even the implied warranty of MERCHANTABILITY or FITNESS FOR A
# PARTICULAR PURPOSE.  See the GNU General Public License for more
# details; it is available at <http://www.fsf.org/copyleft/gpl.html>,
# or by writing to the Free Software Foundation, Inc., 59 Temple Place
# - Suite 330, Boston, MA 02111-1307, USA.

"""gp_win32 -- an interface to gnuplot for Windows.

"""

__cvs_version__ = '$Revision: 2.9 $'


# ############ Configuration variables: ################################

class GnuplotOpts:
    """The configuration options for gnuplot under windows.

    See gp_unix.py for details about the meaning of these options.
    Please let me know if you know better choices for these settings.

    """

    # Command to start up the gnuplot program.  Note that on windows
    # the main gnuplot program cannot be used directly because it can
    # not read commands from standard input.  See README for more
    # information.
    gnuplot_command = 'pgnuplot.exe'

    # The '-persist' option is not supported on windows:
    recognizes_persist = 0

    # As far as I know, gnuplot under windows can use binary data:
    recognizes_binary_splot = 1

    # Apparently gnuplot on windows can use inline data, but we use
    # non-inline data (i.e., temporary files) by default for no
    # special reason:
    prefer_inline_data = 0

    # The default choice for the 'set term' command (to display on
    # screen):
    default_term = 'windows'

    # According to the gnuplot help manual, the following can be used
    # to print directly to a printer under windows.  (Of course it
    # won't help if your printer can't handle postscript!)
    default_lpr = 'PRN'

    # Used the 'enhanced' option of postscript by default?  Set to
    # None (*not* 0!) if your version of gnuplot doesn't support
    # enhanced postscript.
    prefer_enhanced_postscript = 1

# ############ End of configuration options ############################


try:
    from sys import hexversion
except ImportError:
    hexversion = 0

if hexversion >= 0x02000000:
    # Apparently at least as of Python 2.0b1, popen support for
    # windows is adequate.  Give that a try:
    from os import popen
else:
    # For earlier versions, you have to have the win32 extensions
    # installed and we use the popen that it provides.
    from win32pipe import popen


# Mac doesn't recognize persist.
def test_persist():
    return 0


class GnuplotProcess:
    """Unsophisticated interface to a running gnuplot program.

    See gp_unix.py for usage information.

    """

    def __init__(self, persist=0):
        """Start a gnuplot process.

        Create a 'GnuplotProcess' object.  This starts a gnuplot
        program and prepares to write commands to it.

        Keyword arguments:

            'persist' -- the '-persist' option is not supported under
                Windows so this argument must be zero.

        """

        assert not persist, '-persist is not supported under Windows!'

        self.gnuplot = popen(GnuplotOpts.gnuplot_command, 'w')

        # forward write and flush methods:
        self.write = self.gnuplot.write
        self.flush = self.gnuplot.flush

    def __call__(self, s):
        """Send a command string to gnuplot, followed by newline."""

        self.write(s + '\n')
        self.flush()