BUG: Fix clean up of canvastools

NOTE: The rectangle tool doesn't seem to clean up properly.

skimage/viewer/canvastools/base.py

@@ -84,6 +84,16 @@ class CanvasToolBase(object):
         for artist in self._artists:
             self.ax.draw_artist(artist)
 
+    def remove(self):
+        """Remove artists and events from axes.
+
+        Note that the naming here mimics the interface of Matplotlib artists.
+        """
+        #TODO: For some reason, RectangleTool doesn't get properly removed
+        self.disconnect_events()
+        for a in self._artists:
+            a.remove()
+
     def redraw(self):
         """Redraw image and canvas artists.
 

skimage/viewer/plugins/base.py

@@ -44,8 +44,9 @@ class Plugin(QDialog):
     name : str
         Name of plugin. This is displayed as the window title.
     artist : list
-        List of Matplotlib artists. Any artists created by the plugin should
-        be added to this list so that it gets cleaned up on close.
+        List of Matplotlib artists and canvastools. Any artists created by the
+        plugin should be added to this list so that it gets cleaned up on
+        close.
 
     Examples
     --------
@@ -190,8 +191,7 @@ class Plugin(QDialog):
     def closeEvent(self, event):
         """On close disconnect all artists and events from ImageViewer.
 
-        Note that events must be connected using `self.connect_image_event` and
-        artists must be appended to `self.artists`.
+        Note that artists must be appended to `self.artists`.
         """
         self.disconnect_image_events()
         self.remove_image_artists()
@@ -222,6 +222,6 @@ class Plugin(QDialog):
             self.image_viewer.disconnect_event(c)
 
     def remove_image_artists(self):
-        """Disconnect artists that are connected to the image viewer."""
+        """Remove artists that are connected to the image viewer."""
         for a in self.artists:
-            self.image_viewer.remove_artist(a)
+            a.remove()

skimage/viewer/plugins/crop.py

@@ -21,6 +21,7 @@ class Crop(Plugin):
         self.rect_tool = RectangleTool(self.image_viewer.ax,
                                        maxdist=self.maxdist,
                                        on_enter=self.crop)
+        self.artists.append(self.rect_tool)
 
     def help(self):
         helpstr = ("Crop tool",

skimage/viewer/plugins/measure.py

@@ -35,6 +35,7 @@ class Measure(Plugin):
         self.line_tool = LineTool(self.image_viewer.ax,
                                   maxdist=self.maxdist,
                                   on_move=self.line_changed)
+        self.artists.append(self.line_tool)
 
     def help(self):
         helpstr = ("Measure tool",

skimage/viewer/viewers/core.py

@@ -83,14 +83,6 @@ class ImageViewer(QMainWindow):
         self.image = image.copy()
         self.plugins = []
 
-        # List of axes artists to check for removal.
-        self._axes_artists = [self.ax.artists,
-                              self.ax.collections,
-                              self.ax.images,
-                              self.ax.lines,
-                              self.ax.patches,
-                              self.ax.texts]
-
         self.layout = QtGui.QVBoxLayout(self.main_widget)
         self.layout.addWidget(self.canvas)
 
@@ -196,25 +188,6 @@ class ImageViewer(QMainWindow):
         """Disconnect callback by its id (returned by `connect_event`)."""
         self.canvas.mpl_disconnect(callback_id)
 
-    def remove_artist(self, artist):
-        """Disconnect matplotlib artist from image viewer.
-
-        The `closeEvent` method of a Plugin should remove artists (Matplotlib
-        lines, markers, etc.) from the viewer so that they aren't stranded.
-
-        Parameters
-        ----------
-        artist : Matplotlib Artist
-            Artists created by Matplotlib functions (e.g., `plot` returns list
-            of `Line2D` artists) should be saved by the plugin for removal.
-        """
-        # Note: an `add_artist` method is unnecessary since Matplotlib
-
-        # There's probably a smarter way to find where the artist is stored.
-        for artist_list in self._axes_artists:
-            if artist in artist_list:
-                artist_list.remove(artist)
-
     def _update_status_bar(self, event):
         if event.inaxes and event.inaxes.get_navigate():
             self.status_message(self._format_coord(event.xdata, event.ydata))