* Exchanged LightSource shade parameters vmin and vmax with norm

bensullivan2 · bensullivan2 · commit 35c51d5a6304 · 2013-12-05T12:18:18.000+01:00
parameter. * Added LightSource test case similar to example http://matplotlib.org/examples/pylab_examples/shading_example.html
diff --git a/lib/matplotlib/colors.py b/lib/matplotlib/colors.py
@@ -1355,22 +1355,20 @@ def __init__(self, azdeg=315, altdeg=45,
         self.hsv_min_sat = hsv_min_sat
         self.hsv_max_sat = hsv_max_sat
 
-    def shade(self, data, cmap, vmin=None, vmax=None):
+    def shade(self, data, cmap, norm=None):
         """
         Take the input data array, convert to HSV values in the
         given colormap, then adjust those color values
-        to given the impression of a shaded relief map with a
+        to give the impression of a shaded relief map with a
         specified light source.
         RGBA values are returned, which can then be used to
         plot the shaded image with imshow.
         """
 
-        if vmin is None:
-            vmin = data.min()
-        if vmax is None:
-            vmax = data.max()
+        if norm is None:
+            norm = Normalize(vmin=data.min(), vmax=data.max())
 
-        rgb0 = cmap((data - vmin) / (vmax - vmin))
+        rgb0 = cmap((data - norm.vmin) / (norm.vmax - norm.vmin))
         rgb1 = self.shade_rgb(rgb0, elevation=data)
         rgb0[:, :, 0:3] = rgb1
         return rgb0
diff --git a/lib/matplotlib/tests/test_colors.py b/lib/matplotlib/tests/test_colors.py
@@ -204,6 +204,31 @@ def gray_from_float_rgba():
     assert_raises(ValueError, gray_from_float_rgb)
     assert_raises(ValueError, gray_from_float_rgba)
 
+def test_light_source_shading_color_range():
+    # see also http://matplotlib.org/examples/pylab_examples/shading_example.html
+    from matplotlib.colors import LightSource
+
+    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.
+    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()
 
 if __name__ == '__main__':
     import nose
