Merged revisions 8931 via svnmerge from

WeatherGod · WeatherGod · commit 5c6f81d8e6a3 · 2011-01-21T21:50:16.000Z
https://matplotlib.svn.sourceforge.net/svnroot/matplotlib/branches/v1_0_maint ........ r8931 | weathergod | 2011-01-21 15:42:45 -0600 (Fri, 21 Jan 2011) | 3 lines Fixes colors normalization with 'under' colors in LinearSegmentedColormap (values between -1 and 0 were being made positive due to an int cast). Thanks to Eoghan Harrington for discovering and supplying the patch! ........ svn path=/trunk/matplotlib/; revision=8932
diff --git a/lib/matplotlib/colors.py b/lib/matplotlib/colors.py
@@ -523,6 +523,10 @@ def __call__(self, X, alpha=None, bytes=False):
                 np.clip(xa * self.N, -1, self.N, out=xa)
             else:
                 xa = np.clip(xa * self.N, -1, self.N)
+
+            # ensure that all 'under' values will still have negative
+            # value after casting to int
+            np.putmask(xa, xa<0.0, -1)
             xa = xa.astype(int)
         # Set the over-range indices before the under-range;
         # otherwise the under-range values get converted to over-range.
