Validate rcParams["image.origin"]. (#12898)

anntzer · timhoffm · commit 66126d918e3a · 2018-11-27T21:36:21.000+01:00
diff --git a/lib/matplotlib/contour.py b/lib/matplotlib/contour.py
@@ -1752,8 +1752,7 @@ def _initialize_x_y(self, z):
             - 'lower': ``Z[0, 0]`` is at X=0.5, Y=0.5 in the lower left corner.
             - 'upper': ``Z[0, 0]`` is at X=N+0.5, Y=0.5 in the upper left
               corner.
-            - 'image': Use the value from :rc:`image.origin`. Note: The value
-              *None* in the rcParam is currently handled as 'lower'.
+            - 'image': Use the value from :rc:`image.origin`.
 
         extent : (x0, x1, y0, y1), optional
             If *origin* is not *None*, then *extent* is interpreted as
diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
@@ -1150,7 +1150,8 @@ def _validate_linestyle(ls):
     'image.interpolation': ['nearest', validate_string],
     'image.cmap':          ['viridis', validate_string],        # one of gray, jet, etc
     'image.lut':           [256, validate_int],  # lookup table
-    'image.origin':        ['upper', validate_string],  # lookup table
+    'image.origin':        ['upper',
+                            ValidateInStrings('image.origin', ['upper', 'lower'])],
     'image.resample':      [True, validate_bool],
     # Specify whether vector graphics backends will combine all images on a
     # set of axes into a single composite image
