Attempt to clean up back-end setting

- Removes warning message
- Add another method to change the backend

tupak/core/utils.py

@@ -4,6 +4,7 @@ import os
 import numpy as np
 from math import fmod
 import argparse
+import traceback
 
 # Constants
 
@@ -298,13 +299,18 @@ def set_up_command_line_arguments():
 command_line_args = set_up_command_line_arguments()
 
 if 'DISPLAY' in os.environ:
+    logging.debug("DISPLAY={} environment found".format(os.environ['DISPLAY']))
     pass
 else:
     logging.info('No $DISPLAY environment variable found, so importing \
                   matplotlib.pyplot with non-interactive "Agg" backend.')
     import matplotlib
-    matplotlib.use('Agg')
-
-
-
-
+    non_gui_backends = matplotlib.rcsetup.non_interactive_bk
+    for backend in non_gui_backends:
+        try:
+            logging.debug("Trying backend {}".format(backend))
+            matplotlib.use(backend, warn=False)
+            matplotlib.pyplot.switch_backend(backend)
+            break
+        except Exception as e:
+            print(traceback.format_exc())