custom legends example

choldgraf · choldgraf · commit 058dda7f30a0 · 2017-10-17T14:29:17.000-07:00
diff --git a/examples/text_labels_and_annotations/custom_legends.py b/examples/text_labels_and_annotations/custom_legends.py
@@ -0,0 +1,68 @@
+"""
+========================
+Composing Custom Legends
+========================
+
+Composing custom legends piece-by-piece.
+
+.. note::
+
+   For more information on creating and customizing legends, see the following
+   pages:
+
+   * :ref:`sphx_glr_tutorials_intermediate_legend_guide.py`
+   * :ref:`sphx_glr_gallery_text_labels_and_annotations_legend_demo.py`
+
+Sometimes you don't want a legend that is explicitly tied to data that
+you have plotted. For example, say you have plotted 10 lines, but don't
+want a legend item to show up for each one. If you simply plot the lines
+and call ``ax.legend()``, you will get the following:
+"""
+# sphinx_gallery_thumbnail_number = 2
+from matplotlib import rcParams, cycler
+import matplotlib.pyplot as plt
+import numpy as np
+
+N = 10
+data = [np.logspace(0, 1, 100) + np.random.randn(100) + ii for ii in range(N)]
+data = np.array(data).T
+cmap = plt.cm.coolwarm
+rcParams['axes.prop_cycle'] = cycler(color=cmap(np.linspace(0, 1, N)))
+
+fig, ax = plt.subplots()
+lines = ax.plot(data)
+ax.legend(lines)
+
+##############################################################################
+# Note that one legend item per line was created.
+# In this case, we can compose a legend using Matplotlib objects that aren't
+# explicitly tied to the data that was plotted. For example:
+
+from matplotlib.lines import Line2D
+custom_lines = [Line2D([0], [0], color=cmap(0.), lw=4),
+                Line2D([0], [0], color=cmap(.5), lw=4),
+                Line2D([0], [0], color=cmap(1.), lw=4)]
+
+fig, ax = plt.subplots()
+lines = ax.plot(data)
+ax.legend(custom_lines, ['Cold', 'Medium', 'Hot'])
+
+
+###############################################################################
+# There are many other Matplotlib objects that can be used in this way. In the
+# code below we've listed a few common ones.
+
+from matplotlib.patches import Patch
+from matplotlib.lines import Line2D
+
+legend_elements = [Line2D([0], [0], color='b', lw=4, label='Line'),
+                   Line2D([0], [0], marker='o', color='w', label='Scatter',
+                          markerfacecolor='g', markersize=15),
+                   Patch(facecolor='orange', edgecolor='r',
+                         label='Color Patch')]
+
+# Create the figure
+fig, ax = plt.subplots()
+ax.legend(handles=legend_elements, loc='center')
+
+plt.show()
