Improved comment for data spine transform adjustment - taken from mdboom.

cimarronm · cimarronm · commit c1546748d326 · 2013-05-01T08:15:51.000-07:00
diff --git a/lib/matplotlib/spines.py b/lib/matplotlib/spines.py
@@ -324,7 +324,10 @@ def _calc_offset_transform(self):
                                          mtransforms.IdentityTransform())
         elif position_type == 'data':
             if self.spine_type in ('right', 'top'):
-                amount -= 1   # translate left by one to account for right/top data offset of one
+                # The right and top spines have a default position of 1 in
+                # axes coordinates.  When specifying the position in data
+                # coordinates, we need to calculate the position relative to 0.
+                amount -= 1
             if self.spine_type in ('left', 'right'):
                 self._spine_transform = ('data',
                                          mtransforms.Affine2D().translate(
