Merge pull request matplotlib#1626 from piti118/legend_frame_alpha

Add framealpha argument for legend

Author: mdboom

examples/pylab_examples/legend_auto.py

@@ -18,7 +18,7 @@ def fig_1():
     figure(1)
     t = arange(0, 40.0 * pi, 0.1)
     l, = plot(t, 100*sin(t), 'r', label='sine')
-    legend()
+    legend(framealpha=0.5)
 
 def fig_2():
     figure(2)

lib/matplotlib/axes.py

@@ -4448,6 +4448,9 @@ def legend(self, *args, **kwargs):
             If *True*, draw a shadow behind legend. If *None*,
             use rc settings.
 
+          *framealpha*: [*None* | float]
+            If not None, alpha channel for legend frame. Default *None*.
+        
           *ncol* : integer
             number of columns. default is 1
 

lib/matplotlib/legend.py

@@ -167,6 +167,9 @@ def __init__(self, parent, handles, labels,
                                  # box, none use rc
                  shadow=None,
                  title=None,  # set a title for the legend
+
+                 framealpha=None, # set frame alpha
+
                  bbox_to_anchor=None,  # bbox that the legend will be anchored.
                  bbox_transform=None,  # transform for the bbox
                  frameon=None,  # draw frame
@@ -195,6 +198,7 @@ def __init__(self, parent, handles, labels,
         fancybox           if True, draw a frame with a round fancybox.
                            If None, use rc
         shadow             if True, draw a shadow behind legend
+        framealpha         If not None, alpha channel for the frame.
         ncol               number of columns
         borderpad          the fractional whitespace inside the legend border
         labelspacing       the vertical space between the legend entries
@@ -384,6 +388,9 @@ def __init__(self, parent, handles, labels,
         # init with null renderer
         self._init_legend_box(handles, labels)
 
+        if framealpha is not None:
+          self.get_frame().set_alpha(framealpha)
+
         self._loc = loc
 
         self.set_title(title)