use docopt and provide more options

examples/simple_plot.py

@@ -1,46 +1,83 @@
 #! /usr/bin/env python
 #
-#   a simple matplotlib plot - testing for pipelines
+#   a simple matplotlib plot - testing for capabilities
 #
 #   parent shell can optionally do:
 #       export MPLBACKEND=agg
 #
-_version = "3-sep-2023"
-_mode = 0
+_version = "7-sep-2023"
+
+_help = """Usage: simple_plot.py [options]
+
+-p --plotfile PLOTFILE  Plotfile. Optional.
+-b --backend BACKEND    Optional MPLBACKEND to use
+-s --show               Show available backends
+-d --debug              More debugging output?
+-h --help               This help
+-v --version            Script version
+
+This script allows you to easily test for matplotlib's
+capabilities in terms of picking interactive plotting
+vs. creating a plotfile, and selecting a backend
+if the default is not sufficient.
+
+By default the script should bring up an interactive plot
+and report in the title what backend was used.
+"""
 
 import os
 import sys
-
 import numpy as np
+from docopt import docopt
 
-if __name__ == "__main__":
-    if len(sys.argv) > 1:
-        _mode = int(sys.argv[1])
-        plotfile = 'simple_plot.png'
-    else:
-        _mode = 0
-        plotfile = None
 
-    import matplotlib
-    if _mode == 0:
-        matplotlib.use('qt5agg')
-    else:
-        matplotlib.use('agg')
-    import matplotlib.pyplot as plt
+av = docopt(_help, options_first=True, version=_version)
+_debug = av['--debug']
+if _debug:
+    print(av)
+
+plotfile = av['--plotfile']
+backend = av['--backend']
+_mode = -1
+
+
+import matplotlib
+if av['--show']:
+    gui_env = [i for i in matplotlib.rcsetup.interactive_bk]
+    non_gui_backends = matplotlib.rcsetup.non_interactive_bk
+    print ("Non Gui backends are:", non_gui_backends)
+    print ("Gui backends I will test for", gui_env)
+    sys.exit(0)
+
+
+if plotfile is not None:
+    matplotlib.use('agg')
+
+if backend is not None:
+    matplotlib.use(backend)
+
+import matplotlib.pyplot as plt
+
+if _debug:
     if 'MPLBACKEND' in os.environ:
         print('$MPLBACKEND :',os.environ['MPLBACKEND'])
     else:
         print("no $MPLBACKEND used")
-    print('mpl backend :',matplotlib.get_backend())
 
-    x = np.arange(0,2,0.1)
-    y = np.sqrt(x)
-
-    plt.figure()
-    plt.plot(x,y, label="test");
-    plt.legend()
-    if plotfile == None:
-        plt.show()
-    else:
-        plt.savefig(plotfile)
-        print("Wrote",plotfile)
+backend = matplotlib.get_backend()
+if _debug:
+    print('mpl backend :',backend)
+
+x = np.arange(0,2,0.1)
+y = np.sqrt(x)
+
+plt.figure()
+plt.plot(x,y, label="test");
+plt.legend()
+msg = f"plotfile={plotfile} mode={_mode} backend={backend}"
+plt.title(msg)
+if plotfile == None:
+    plt.show()
+else:
+    plt.savefig(plotfile)
+    print("Wrote",plotfile)