Package PyFoam :: Package ThirdParty :: Package Gnuplot :: Module gp_unix
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Source Code for Module PyFoam.ThirdParty.Gnuplot.gp_unix

  1  # $Id: gp_unix.py 292 2006-03-03 09:49:04Z mhagger $ 
  2   
  3  # Copyright (C) 1998-2003 Michael Haggerty <mhagger@alum.mit.edu> 
  4  # 
  5  # This file is licensed under the GNU Lesser General Public License 
  6  # (LGPL).  See LICENSE.txt for details. 
  7   
  8  """gp_unix -- an interface to gnuplot used for unix platforms. 
  9   
 10  This file implements a low-level interface to a gnuplot program for a 
 11  unix platform (actually it is used for any non-Windows, non-Mac 
 12  system).  This file should be imported through gp.py, which in turn 
 13  should be imported via 'import Gnuplot' rather than these low-level 
 14  interfaces. 
 15   
 16  """ 
 17   
 18  # ############ Configuration variables: ################################ 
 19   
20 -class GnuplotOpts:
21 """The configuration options for gnuplot on generic platforms. 22 23 Store the options in a class to make them easy to import and 24 modify en masse. If you want to modify the options from the 25 command line or within a running program, do something like the 26 following:: 27 28 import Gnuplot 29 Gnuplot.GnuplotOpts.gnuplot_command = '/bin/mygnuplot' 30 31 """ 32 33 # Command to start up the gnuplot program. If your version of 34 # gnuplot is run otherwise, specify the correct command here. You 35 # could also specify a full path or append command-line options 36 # here if you wish. 37 gnuplot_command = 'gnuplot' 38 39 # Recent versions of gnuplot (at least for Xwindows) allow a 40 # `-persist' command-line option when starting up gnuplot. When 41 # this option is specified, graph windows remain on the screen 42 # even after you quit gnuplot (type `q' in the window to close 43 # it). This can be handy but unfortunately it is not supported by 44 # older versions of gnuplot. The following configuration variable 45 # specifies whether the user's version of gnuplot recognizes this 46 # option or not. You can set this variable to 1 (supports 47 # -persist) or 0 (doesn't support) yourself; if you leave it with 48 # the value None then the first time you create a Gnuplot object 49 # it will try to detect automatically whether your version accepts 50 # this option. 51 recognizes_persist = None # test automatically on first use 52 53 # What should be the default if the persist option is not 54 # specified explicitly? 55 prefer_persist = 0 56 57 # Recent versions of gnuplot allow you to specify a `binary' 58 # option to the splot command for grid data, which means that the 59 # data file is to be read in binary format. This option saves 60 # substantial time writing and reading the file, and can also save 61 # substantial disk space and therefore it is the default for that 62 # type of plot. But if you have an older version of gnuplot (or 63 # you prefer text format) you can disable the binary option in 64 # either of two ways: (a) set the following variable to 0; or (b) 65 # pass `binary=0' to the GridData constructor. (Note that the 66 # demo uses binary=0 to maximize portability.) 67 recognizes_binary_splot = 1 68 69 # Data can be passed to gnuplot through a temporary file or as 70 # inline data (i.e., the filename is set to '-' and the data is 71 # entered into the gnuplot interpreter followed by 'e'). If 72 # prefer_inline_data is true, then use the inline method as 73 # default whenever it is supported. This should be fast but will 74 # use more memory since currently the inline data is put into a 75 # big string when the PlotItem is created. 76 prefer_inline_data = 0 77 78 # Does Python implement the threading module and os.mkfifo on this 79 # operating system? If so, the _FIFOFileItem class will be 80 # defined in PlotItem.py. 81 support_fifo = 1 82 83 # Should FIFOs be used to send data to gnuplot by default? 84 prefer_fifo_data = 1 85 86 # After a hardcopy is produced, we have to set the terminal type 87 # back to `on screen' using gnuplot's `set terminal' command. The 88 # following is the usual setting for Xwindows. If it is wrong, 89 # change the following line to select the terminal type you prefer 90 # to use for on-screen work. 91 default_term = 'x11' 92 93 # Gnuplot can plot to a printer by using "set output '| ...'" 94 # where ... is the name of a program that sends its stdin to a 95 # printer, or by "set output 'printer_device', where 96 # 'printer_device is the name of a file-like interface to the 97 # printer. On my machine the appropriate program is `lpr', as set 98 # below. On your computer it may be something different (like 99 # `lp'); you can set that by changing the variable below. You can 100 # also add options to the print command if needed. 101 default_lpr = '| lpr' 102 103 # Enhanced postscript is an option to the postscript terminal 104 # driver that requests enhanced treatment of strings (for example, 105 # font changes, superscripts, and subscripts). Set to 1 to enable 106 # or 0 to disable. If you have a version of gnuplot earlier than 107 # 3.7, you should set this to None (*not* 0!) so that the option 108 # is not used at all. 109 prefer_enhanced_postscript = 1
110 111 # ############ End of configuration options ############################ 112 113 from os import popen 114 115
116 -def test_persist():
117 """Determine whether gnuplot recognizes the option '-persist'. 118 119 If the configuration variable 'recognizes_persist' is set (i.e., 120 to something other than 'None'), return that value. Otherwise, 121 try to determine whether the installed version of gnuplot 122 recognizes the -persist option. (If it doesn't, it should emit an 123 error message with '-persist' in the first line.) Then set 124 'recognizes_persist' accordingly for future reference. 125 126 """ 127 128 if GnuplotOpts.recognizes_persist is None: 129 import string 130 g = popen('echo | %s -persist 2>&1' % GnuplotOpts.gnuplot_command, 'r') 131 response = g.readlines() 132 g.close() 133 GnuplotOpts.recognizes_persist = ( 134 (not response) or (string.find(response[0], '-persist') == -1)) 135 return GnuplotOpts.recognizes_persist
136 137
138 -class GnuplotProcess:
139 """Unsophisticated interface to a running gnuplot program. 140 141 This represents a running gnuplot program and the means to 142 communicate with it at a primitive level (i.e., pass it commands 143 or data). When the object is destroyed, the gnuplot program exits 144 (unless the 'persist' option was set). The communication is 145 one-way; gnuplot's text output just goes to stdout with no attempt 146 to check it for error messages. 147 148 Members: 149 150 'gnuplot' -- the pipe to the gnuplot command. 151 152 Methods: 153 154 '__init__' -- start up the program. 155 156 '__call__' -- pass an arbitrary string to the gnuplot program, 157 followed by a newline. 158 159 'write' -- pass an arbitrary string to the gnuplot program. 160 161 'flush' -- cause pending output to be written immediately. 162 163 'close' -- close the connection to gnuplot. 164 165 """ 166
167 - def __init__(self, persist=None):
168 """Start a gnuplot process. 169 170 Create a 'GnuplotProcess' object. This starts a gnuplot 171 program and prepares to write commands to it. 172 173 Keyword arguments: 174 175 'persist=1' -- start gnuplot with the '-persist' option, 176 (which leaves the plot window on the screen even after 177 the gnuplot program ends, and creates a new plot window 178 each time the terminal type is set to 'x11'). This 179 option is not available on older versions of gnuplot. 180 181 """ 182 183 if persist is None: 184 persist = GnuplotOpts.prefer_persist 185 if persist: 186 if not test_persist(): 187 raise ('-persist does not seem to be supported ' 188 'by your version of gnuplot!') 189 self.gnuplot = popen('%s -persist' % GnuplotOpts.gnuplot_command, 190 'w') 191 else: 192 self.gnuplot = popen(GnuplotOpts.gnuplot_command, 'w') 193 194 # forward write and flush methods: 195 self.write = self.gnuplot.write 196 self.flush = self.gnuplot.flush
197
198 - def close(self):
199 if self.gnuplot is not None: 200 self.gnuplot.close() 201 self.gnuplot = None
202
203 - def __del__(self):
204 self.close()
205
206 - def __call__(self, s):
207 """Send a command string to gnuplot, followed by newline.""" 208 209 self.write(s + '\n') 210 self.flush()
211