Resolves matplotlib#1246 exception. Agg backend works beautifully, PDF and SVG fail to produce suitable results.

Author: pelson

lib/matplotlib/scale.py

@@ -115,6 +115,7 @@ class LogTransformBase(Transform):
         input_dims = 1
         output_dims = 1
         is_separable = True
+        has_inverse = True
 
         def __init__(self, nonpos):
             Transform.__init__(self)
@@ -316,6 +317,7 @@ class SymmetricalLogTransform(Transform):
         input_dims = 1
         output_dims = 1
         is_separable = True
+        has_inverse = True
 
         def __init__(self, base, linthresh, linscale):
             Transform.__init__(self)