Problem: Can't combine mouse button events and pick events in a scatter plot

Hello everybody,

I am trying to combine mouse button events with a pick event in scatter
plot. Different functionalities take place, based on the mouse button
pressed each time. I want each functionality to be triggered with a
combination of mouse buttons events and/or key press events. When the left
mouse button is pressed matplotlib's Lasso widget is called and with the
included points functionality 1 takes place. When Shift+LMB are pressed a
Lasso is drawn and functionality 2 takes place with the included points.
When Alt+LMB are pressed a Lasso is drawn and with the included points
functionality 3 takes place. Last, but not least, when I press the RMB a
pick event is triggered and the index of the selected point in the scatter
plot is given.

Since I added the pick event, the aforementioned functionalities work
correctly until a pick event is triggered. When it is triggered it seems
that the canvas gets locked and I can not use any other functionality. I
don't get the index of the selected points and I do not get any errors.

Code :

import logging
import matplotlib
from matplotlib.widgets import Lasso
from matplotlib.colors import colorConverter
from matplotlib.collections import RegularPolyCollection
from matplotlib import path
import numpy as np
import matplotlib.pyplot as plt
from numpy.random import rand

logger = logging.getLogger()

class Datum(object):
      colorin = colorConverter.to_rgba('red')
      colorShift = colorConverter.to_rgba('cyan')
      colorCtrl = colorConverter.to_rgba('pink')
      colorout = colorConverter.to_rgba('blue')

      def __init__(self, x, y, include=False):
         self.x = x
         self.y = y
         if include:
            self.color = self.colorin
            self.color = self.colorout

class LassoManager(object):
      def __init__(self, ax, data):
         self.axes = ax
         self.canvas = ax.figure.canvas = data

         self.Nxy = len(data)

         facecolors = [d.color for d in data]
         self.xys = [(d.x, d.y) for d in data]
         fig = ax.figure
         self.collection = RegularPolyCollection(fig.dpi, 6,
sizes=(100,),facecolors=facecolors, offsets = self.xys, transOffset =


         self.pick=self.canvas.mpl_connect('pick_event', self.onpick)
         self.cid = self.canvas.mpl_connect('button_press_event',
         self.keyPress = self.canvas.mpl_connect('key_press_event',
         self.keyRelease = self.canvas.mpl_connect('key_release_event',
         self.lasso = None
         self.shiftKey = False
         self.ctrlKey = False

      def callback(self, verts):
          logging.debug('in LassoManager.callback(). Shift: %s, Ctrl: %s' %
(self.shiftKey, self.ctrlKey))
          facecolors = self.collection.get_facecolors()
          p = path.Path(verts)
          ind = p.contains_points(self.xys)
          for i in range(len(self.xys)):
              if ind[i]:
                 if self.shiftKey:
                    facecolors[i] = Datum.colorShift
                 elif self.ctrlKey:
                    facecolors[i] = Datum.colorCtrl
                    facecolors[i] = Datum.colorin
                    print self.xys[i]
                   facecolors[i] = Datum.colorout

          del self.lasso

      def onpress(self, event):
           if self.canvas.widgetlock.locked(): return
           if event.inaxes is None: return
           self.lasso = Lasso(event.inaxes, (event.xdata, event.ydata),
           # acquire a lock on the widget drawing

      def onKeyPress(self, event):
          logging.debug('in LassoManager.onKeyPress(). Event received: %s
(key: %s)' % (event, event.key))
          if event.key == 'alt':
             self.ctrlKey = True
          if event.key == 'shift':
             self.shiftKey = True

      def onKeyRelease(self, event):
          logging.debug('in LassoManager.onKeyRelease(). Event received: %s
(key: %s)' % (event, event.key))
          if event.key == 'alt':
             self.ctrlKey = False
          if event.key == 'shift':
             self.shiftKey = False

      def onpick(self,event):

          if event.mouseevent.button == 3:

             index = event.ind
             print('onpick3 scatter:', index)

      if __name__ == '__main__':

         data = [Datum(*xy) for xy in rand(100, 2)]

         ax = plt.axes(xlim=(0,1), ylim=(0,1), autoscale_on=False)
         lman = LassoManager(ax, data)

Any suggestions on what might be causing this malfunction? What am I doing


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