From b83977f46806b35e258413db63618b58e2ef0d02 Mon Sep 17 00:00:00 2001
From: Benjamin Root <ben.v.root@gmail.com>
Date: Fri, 28 Jun 2013 18:55:21 -0400
Subject: [PATCH] Much better alpha control in mplot3d. Closes #1541

Probably haven't solved them all, but this gets most of them.
---
 lib/mpl_toolkits/mplot3d/art3d.py | 36 ++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/lib/mpl_toolkits/mplot3d/art3d.py b/lib/mpl_toolkits/mplot3d/art3d.py
index 53ba0fe2e559..6b9d2a45eba5 100644
--- a/lib/mpl_toolkits/mplot3d/art3d.py
+++ b/lib/mpl_toolkits/mplot3d/art3d.py
@@ -9,6 +9,7 @@
 '''
 
 from matplotlib import lines, text as mtext, path as mpath, colors as mcolors
+from matplotlib import artist
 from matplotlib.collections import Collection, LineCollection, \
         PolyCollection, PatchCollection
 from matplotlib.cm import ScalarMappable
@@ -318,9 +319,13 @@ def do_3d_projection(self, renderer):
         xs, ys, zs = self._offsets3d
         vxs, vys, vzs, vis = proj3d.proj_transform_clip(xs, ys, zs, renderer.M)
         #FIXME: mpl allows us no way to unset the collection alpha value
-        self._alpha = None
-        self.set_facecolors(zalpha(self._facecolor3d, vzs))
-        self.set_edgecolors(zalpha(self._edgecolor3d, vzs))
+        #self._alpha = None
+        fcs = mcolors.colorConverter.to_rgba_array(self._facecolor3d,
+                                                   self._alpha)
+        mcs = mcolors.colorConverter.to_rgba_array(self._edgecolor3d,
+                                                   self._alpha)
+        self.set_facecolors(zalpha(fcs, vzs))
+        self.set_edgecolors(zalpha(mcs, vzs))
         PatchCollection.set_offsets(self, zip(vxs, vys))
 
         if vzs.size > 0 :
@@ -427,6 +432,7 @@ def set_3d_properties(self):
         self.set_zsort(True)
         self._facecolors3d = PolyCollection.get_facecolors(self)
         self._edgecolors3d = PolyCollection.get_edgecolors(self)
+        self._alpha3d = PolyCollection.get_alpha(self)
 
     def set_sort_zpos(self,val):
         '''Set the position to use for z-sorting.'''
@@ -495,6 +501,30 @@ def set_edgecolor(self, colors):
         self._edgecolors3d = PolyCollection.get_edgecolor(self)
     set_edgecolors = set_edgecolor
 
+    def set_alpha(self, alpha):
+        """
+        Set the alpha tranparencies of the collection.  *alpha* must be
+        a float or *None*.
+
+        ACCEPTS: float or None
+        """
+        if alpha is not None:
+            try:
+                float(alpha)
+            except TypeError:
+                raise TypeError('alpha must be a float or None')
+        artist.Artist.set_alpha(self, alpha)
+        try:
+            self._facecolors = mcolors.colorConverter.to_rgba_array(
+                self._facecolors3d, self._alpha)
+        except (AttributeError, TypeError, IndexError):
+            pass
+        try:
+            self._edgecolors = mcolors.colorConverter.to_rgba_array(
+                    self._edgecolors3d, self._alpha)
+        except (AttributeError, TypeError, IndexError):
+            pass
+
     def get_facecolors(self):
         return self._facecolors2d
     get_facecolor = get_facecolors