Merge pull request matplotlib#5283 from mdboom/colormap-fixes

Make new colormaps full-fledged citizens

Author: WeatherGod

examples/pylab_examples/demo_bboximage.py

@@ -25,7 +25,7 @@
     a = np.linspace(0, 1, 256).reshape(1, -1)
     a = np.vstack((a, a))
 
-    maps = sorted(m for m in plt.cm.datad if not m.endswith("_r"))
+    maps = sorted(m for m in plt.cm.cmap_d if not m.endswith("_r"))
     #nmaps = len(maps) + 1
 
     #fig.subplots_adjust(top=0.99, bottom=0.01, left=0.2, right=0.99)

lib/matplotlib/cm.py

@@ -146,9 +146,8 @@ def get_cmap(name=None, lut=None):
     returned.
 
     If *lut* is not None it must be an integer giving the number of
-    entries desired in the lookup table, and *name* must be a
-    standard mpl colormap name with a corresponding data dictionary
-    in *datad*.
+    entries desired in the lookup table, and *name* must be a standard
+    mpl colormap name.
     """
     if name is None:
         name = mpl.rcParams['image.cmap']
@@ -159,12 +158,12 @@ def get_cmap(name=None, lut=None):
     if name in cmap_d:
         if lut is None:
             return cmap_d[name]
-        elif name in datad:
-            return _generate_cmap(name, lut)
+        else:
+            return cmap_d[name]._resample(lut)
     else:
         raise ValueError(
             "Colormap %s is not recognized. Possible values are: %s"
-            % (name, ', '.join(cmap_d.keys())))
+            % (name, ', '.join(sorted(cmap_d.keys()))))
 
 
 class ScalarMappable(object):

lib/matplotlib/colors.py

@@ -659,6 +659,12 @@ def is_gray(self):
         return (np.alltrue(self._lut[:, 0] == self._lut[:, 1]) and
                 np.alltrue(self._lut[:, 0] == self._lut[:, 2]))
 
+    def _resample(self, lutsize):
+        """
+        Return a new color map with *lutsize* entries.
+        """
+        raise NotImplementedError()
+
 
 class LinearSegmentedColormap(Colormap):
     """Colormap objects based on lookup tables using linear segments.
@@ -772,6 +778,12 @@ def from_list(name, colors, N=256, gamma=1.0):
 
         return LinearSegmentedColormap(name, cdict, N, gamma)
 
+    def _resample(self, lutsize):
+        """
+        Return a new color map with *lutsize* entries.
+        """
+        return LinearSegmentedColormap(self.name, self._segmentdata, lutsize)
+
 
 class ListedColormap(Colormap):
     """Colormap object generated from a list of colors.
@@ -836,6 +848,12 @@ def _init(self):
         self._isinit = True
         self._set_extremes()
 
+    def _resample(self, lutsize):
+        """
+        Return a new color map with *lutsize* entries.
+        """
+        return ListedColormap(self.name, self.colors, lutsize)
+
 
 class Normalize(object):
     """