matplotlib
diff --git a/‎lib/matplotlib/backend_bases.py
Lines changed: 7 additions & 21 deletions b/‎lib/matplotlib/backend_bases.py
Lines changed: 7 additions & 21 deletions
diff --git a/‎tutorials/colors/colors.py
Lines changed: 14 additions & 1 deletion b/‎tutorials/colors/colors.py
Lines changed: 14 additions & 1 deletion
@@ -1804,7 +1804,6 @@ def is_saving(self):
         """
         return self._is_saving
 
-    @cbook.deprecated("2.2")
     def onRemove(self, ev):
         """
         Mouse event processor which removes the top artist
@@ -2697,7 +2696,6 @@ def key_press(self, event):
         if rcParams['toolbar'] != 'toolmanager':
             key_press_handler(event, self.canvas, self.canvas.toolbar)
 
-    @cbook.deprecated("2.2")
     def show_popup(self, msg):
         """Display message in a popup -- GUI only."""
 
@@ -3220,13 +3218,6 @@ class ToolContainerBase(object):
         The tools with which this `ToolContainer` wants to communicate.
     """
 
-    _icon_extension = '.png'
-    """
-    Toolcontainer button icon image format extension
-
-    **String**: Image extension
-    """
-
     def __init__(self, toolmanager):
         self.toolmanager = toolmanager
         self.toolmanager.toolmanager_connect('tool_removed_event',
@@ -3271,19 +3262,14 @@ def _remove_tool_cbk(self, event):
 
     def _get_image_filename(self, image):
         """Find the image based on its name."""
-        if not image:
-            return None
-
+        # TODO: better search for images, they are not always in the
+        # datapath
         basedir = os.path.join(rcParams['datapath'], 'images')
-        possible_images = (
-            image,
-            image + self._icon_extension,
-            os.path.join(basedir, image),
-            os.path.join(basedir, image) + self._icon_extension)
-
-        for fname in possible_images:
-            if os.path.isfile(fname):
-                return fname
+        if image is not None:
+            fname = os.path.join(basedir, image)
+        else:
+            fname = None
+        return fname
 
     def trigger_tool(self, name):
         """
 
@@ -6,7 +6,7 @@
 Matplotlib recognizes the following formats to specify a color:
 
 * an RGB or RGBA tuple of float values in ``[0, 1]`` (e.g., ``(0.1, 0.2, 0.5)``
-  or  ``(0.1, 0.2, 0.5, 0.3)``);
+  or  ``(0.1, 0.2, 0.5, 0.3)``).  RGBA is short for Red, Green, Blue, Alpha;
 * a hex RGB or RGBA string (e.g., ``'#0F0F0F'`` or ``'#0F0F0F0F'``);
 * a string representation of a float value in ``[0, 1]`` inclusive for gray
   level (e.g., ``'0.5'``);
@@ -23,6 +23,19 @@
   the indexing occurs at artist creation time and defaults to black if the
   cycle does not include color.
 
+"Red", "Green" and "Blue", are the intensities of those colors, the combination
+of which span the colorspace.
+
+How "Alpha" behaves depends on the ``zorder`` of the Artist.  Higher
+`zorder` Artists are drawn on top of lower Artists, and "Alpha" determines
+whether the lower artist is covered by the higher.
+If the old RGB of a pixel is ``RGBold`` and the RGB of the
+pixel of the Artist being added is ``RGBnew`` with Alpha ``alpha``,
+then the RGB of the pixel is updated to:
+``RGB = RGBOld * (1 - Alpha) + RGBnew * Alpha``.  Alpha
+of 1 means the old color is completely covered by the new Artist, Alpha of 0
+means that pixel of the Artist is transparent.
+
 All string specifications of color, other than "CN", are case-insensitive.
 
 "CN" color selection