added state to legend toggle

jdh2358 · jdh2358 · commit fc40214a298f · 2010-01-29T15:27:54.000Z
svn path=/trunk/matplotlib/; revision=8101
diff --git a/CHANGELOG b/CHANGELOG
@@ -1,3 +1,6 @@
+2010-01-29 Added draggable method to Legend to allow mouse drag
+placement.  Thanks Adam Fraser. JDH
+
 2010-01-25 Fixed a bug reported by Olle Engdegard, when using
            histograms with stepfilled and log=True - MM
 
diff --git a/lib/matplotlib/legend.py b/lib/matplotlib/legend.py
@@ -935,16 +935,32 @@ def _find_best_position(self, width, height, renderer, consider=None):
         return ox, oy
 
 
-    def draggable(self):
+    def draggable(self, state=None):
         """
-        toggle the draggable state; if on, you can drag the legend on
-        the canvas.  The DraggableLegend helper class is returned
+        Set the draggable state -- if state is
+
+          * None : toggle the current state
+
+          * True : turn draggable on
+
+          * False : turn draggable off
+          
+        If draggable is on, you can drag the legend on the canvas with
+        the mouse.  The DraggableLegend helper instance is returned if
+        draggable is on.
         """
-        if self._draggable is not None:
-            self._draggable.disconnect()
-            self._draggable = None
+        is_draggable = self._draggable is not None
+
+        # if state is None we'll toggle
+        if state is None:
+            state = not is_draggable
+            
+        if state:
+            if self._draggable is None:
+                self._draggable = DraggableLegend(self)
         else:
-
-            self._draggable = DraggableLegend(self)
+            if self._draggable is not None:
+                self._draggable.disconnect()
+            self._draggable = None
 
         return self._draggable
