- Simplification of norm usage in shade() method

- basic example and assert statement in LightSource test

Author: bensullivan2

lib/matplotlib/colors.py

@@ -1368,7 +1368,7 @@ def shade(self, data, cmap, norm=None):
         if norm is None:
             norm = Normalize(vmin=data.min(), vmax=data.max())
 
-        rgb0 = cmap((data - norm.vmin) / (norm.vmax - norm.vmin))
+        rgb0 = cmap(norm(data))
         rgb1 = self.shade_rgb(rgb0, elevation=data)
         rgb0[:, :, 0:3] = rgb1
         return rgb0

lib/matplotlib/tests/test_colors.py

@@ -210,28 +210,27 @@ def test_light_source_shading_color_range():
     #http://matplotlib.org/examples/pylab_examples/shading_example.html
 
     from matplotlib.colors import LightSource
+    from matplotlib.colors import Normalize
 
-    norm = mcolors.Normalize(vmin=0, vmax=50)
-    # test data
-    X, Y = np.mgrid[-5:5:0.05, -5:5:0.05]
-    Z = np.sqrt(X**2 + Y**2) + np.sin(X**2 + Y**2)
-    # create light source object.
+    refinput = np.array([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]])
+    norm = Normalize(vmin=0, vmax=50)
     ls = LightSource(azdeg=0, altdeg=65)
-    # shade data, creating an rgb array.
-    rgb = ls.shade(Z, plt.cm.jet, norm=norm)
-    # plot un-shaded and shaded images.
-    plt.figure(figsize=(12, 5))
-    plt.subplot(121)
-    plt.imshow(Z, cmap=plt.cm.jet, norm=norm)
-    plt.title('imshow')
-    plt.xticks([])
-    plt.yticks([])
-    plt.subplot(122)
-    plt.imshow(rgb)
-    plt.title('imshow with shading')
-    plt.xticks([])
-    plt.yticks([])
-    plt.draw()
+    testoutput = ls.shade(refinput, plt.cm.jet, norm=norm)
+    refoutput = np.array([
+        [[0., 0., 0.58912656, 1.],
+        [0., 0., 0.67825312, 1.],
+        [0., 0., 0.76737968, 1.],
+        [0., 0., 0.85650624, 1.]],
+        [[0., 0., 0.9456328, 1.],
+        [0., 0., 1., 1.],
+        [0., 0.04901961, 1., 1.],
+        [0., 0.12745098, 1., 1.]],
+        [[0., 0.22156863, 1., 1.],
+        [0., 0.3, 1., 1.],
+        [0., 0.37843137, 1., 1.],
+        [0., 0.45686275, 1., 1.]]
+        ])
+    assert_array_almost_equal(refoutput, testoutput)
 
 
 if __name__ == '__main__':