Merge pull request matplotlib#1152 from ChrisBeaumont/checkable_navbar

checkable pan/zoom buttons for QT NavigationToolbar

Author: pelson

lib/matplotlib/backends/backend_qt4.py

@@ -501,6 +501,9 @@ def __init__(self, canvas, parent, coordinates=True):
         """ coordinates: should we show the coordinates on the right? """
         self.canvas = canvas
         self.coordinates = coordinates
+        self._actions = {}
+        """A mapping of toolitem method names to their QActions"""
+
         QtGui.QToolBar.__init__( self, parent )
         NavigationToolbar2.__init__( self, canvas )
 
@@ -516,6 +519,9 @@ def _init_toolbar(self):
             else:
                 a = self.addAction(self._icon(image_file + '.png'),
                                          text, getattr(self, callback))
+                self._actions[callback] = a
+                if callback in ['zoom', 'pan']:
+                    a.setCheckable(True)
                 if tooltip_text is not None:
                     a.setToolTip(tooltip_text)
 
@@ -574,6 +580,18 @@ def edit_parameters(self):
 
             figureoptions.figure_edit(axes, self)
 
+    def _update_buttons_checked(self):
+        #sync button checkstates to match active mode
+        self._actions['pan'].setChecked(self._active == 'PAN')
+        self._actions['zoom'].setChecked(self._active == 'ZOOM')
+
+    def pan(self, *args):
+        super(NavigationToolbar2QT, self).pan(*args)
+        self._update_buttons_checked()
+
+    def zoom(self, *args):
+        super(NavigationToolbar2QT, self).zoom(*args)
+        self._update_buttons_checked()
 
     def dynamic_update( self ):
         self.canvas.draw()