add message in plot_fundus when loc_od_x has wrong sign

pulse2percept/viz.py

@@ -1,6 +1,7 @@
 import numpy as np
 import matplotlib.pyplot as plt
 from matplotlib import patches
+import logging
 from . import implants
 from . import utils
 from . import retina
@@ -54,6 +55,11 @@ def plot_fundus(implant, stim=None, ax=None, loc_od=(15.5, 1.5), n_bundles=100,
     # Make sure x-coord of optic disc has the correct sign for LE/RE:
     if (implant.eye == 'RE' and loc_od[0] <= 0
             or implant.eye == 'LE' and loc_od[0] > 0):
+        logstr = ("For eye==%s, expected opposite sign of x-coordinate of "
+                  "the optic disc; changing %.3f to %.3f" % (implant.eye,
+                                                             loc_od[0],
+                                                             -loc_od[0]))
+        logging.getLogger(__name__).info(logstr)
         loc_od = (-loc_od[0], loc_od[1])
     if ax is None:
         # No axes object given: create