text: """
  This provides several classes used for blocking interaction with figure
  windows:
  
  :class:`BlockingInput`
      creates a callable object to retrieve events in a blocking way for
      interactive sessions
  
  :class:`BlockingKeyMouseInput`
      creates a callable object to retrieve key or mouse clicks in a blocking
      way for interactive sessions.
      Note: Subclass of BlockingInput. Used by waitforbuttonpress
  
  :class:`BlockingMouseInput`
      creates a callable object to retrieve mouse clicks in a blocking way for
      interactive sessions.
      Note: Subclass of BlockingInput.  Used by ginput
  
  :class:`BlockingContourLabeler`
      creates a callable object to retrieve mouse clicks in a blocking way that
      will then be used to place labels on a ContourSet
      Note: Subclass of BlockingMouseInput.  Used by clabel
  """
  
  from __future__ import (absolute_import, division, print_function,
                          unicode_literals)
  
  import six
  from matplotlib import verbose
  from matplotlib.cbook import is_sequence_of_strings
  import matplotlib.lines as mlines
  
  
  class BlockingInput(object):
      """
      Class that creates a callable object to retrieve events in a
      blocking way.
      """
      def __init__(self, fig, eventslist=()):
          self.fig = fig
          assert is_sequence_of_strings(
              eventslist), "Requires a sequence of event name strings"
          self.eventslist = eventslist
  
      def on_event(self, event):
          """
          Event handler that will be passed to the current figure to
          retrieve events.
          """
          # Add a new event to list - using a separate function is
          # overkill for the base class, but this is consistent with
          # subclasses
          self.add_event(event)
  
          verbose.report("Event %i" % len(self.events))
  
          # This will extract info from events
          self.post_event()
  
          # Check if we have enough events already
          if len(self.events) >= self.n and self.n > 0:
              self.fig.canvas.stop_event_loop()
  
      def post_event(self):
          """For baseclass, do nothing but collect events"""
          pass
  
      def cleanup(self):
          """Disconnect all callbacks"""
          for cb in self.callbacks:
              self.fig.canvas.mpl_disconnect(cb)
  
          self.callbacks = []
  
      def add_event(self, event):
          """For base class, this just appends an event to events."""
          self.events.append(event)
  
      def pop_event(self, index=-1):
          """
          This removes an event from the event list.  Defaults to
          removing last event, but an index can be supplied.  Note that
          this does not check that there are events, much like the
          normal pop method.  If not events exist, this will throw an
          exception.
          """
          self.events.pop(index)
  
      def pop(self, index=-1):
          self.pop_event(index)
      pop.__doc__ = pop_event.__doc__
  
      def __call__(self, n=1, timeout=30):
          """
          Blocking call to retrieve n events
          """
  
          assert isinstance(n, int), "Requires an integer argument"
          self.n = n
  
          self.events = []
          self.callbacks = []
  
          # Ensure that the figure is shown
          self.fig.show()
  
          # connect the events to the on_event function call
          for n in self.eventslist:
              self.callbacks.append(
                  self.fig.canvas.mpl_connect(n, self.on_event))
  
          try:
              # Start event loop
              self.fig.canvas.start_event_loop(timeout=timeout)
          finally:  # Run even on exception like ctrl-c
              # Disconnect the callbacks
              self.cleanup()
  
          # Return the events in this case
          return self.events
  
  
  class BlockingMouseInput(BlockingInput):
      """
      Class that creates a callable object to retrieve mouse clicks in a
      blocking way.
  
      This class will also retrieve keyboard clicks and treat them like
      appropriate mouse clicks (delete and backspace are like mouse button 3,
      enter is like mouse button 2 and all others are like mouse button 1).
      """
  
      button_add = 1
      button_pop = 3
      button_stop = 2
  
      def __init__(self, fig, mouse_add=1, mouse_pop=3, mouse_stop=2):
          BlockingInput.__init__(self, fig=fig,
                                 eventslist=('button_press_event',
                                             'key_press_event'))
          self.button_add = mouse_add
          self.button_pop = mouse_pop
          self.button_stop = mouse_stop
  
      def post_event(self):
          """
          This will be called to process events
          """
          assert len(self.events) > 0, "No events yet"
  
          if self.events[-1].name == 'key_press_event':
              self.key_event()
          else:
              self.mouse_event()
  
      def mouse_event(self):
          '''Process a mouse click event'''
  
          event = self.events[-1]
          button = event.button
  
          if button == self.button_pop:
              self.mouse_event_pop(event)
          elif button == self.button_stop:
              self.mouse_event_stop(event)
          else:
              self.mouse_event_add(event)
  
      def key_event(self):
          '''
          Process a key click event.  This maps certain keys to appropriate
          mouse click events.
          '''
  
          event = self.events[-1]
          if event.key is None:
              # at least in mac os X gtk backend some key returns None.
              return
  
          key = event.key.lower()
  
          if key in ['backspace', 'delete']:
              self.mouse_event_pop(event)
          elif key in ['escape', 'enter']:
              # on windows XP and wxAgg, the enter key doesn't seem to register
              self.mouse_event_stop(event)
          else:
              self.mouse_event_add(event)
  
      def mouse_event_add(self, event):
          """
          Will be called for any event involving a button other than
          button 2 or 3.  This will add a click if it is inside axes.
          """
          if event.inaxes:
              self.add_click(event)
          else:  # If not a valid click, remove from event list
              BlockingInput.pop(self, -1)
  
      def mouse_event_stop(self, event):
          """
          Will be called for any event involving button 2.
          Button 2 ends blocking input.
          """
  
          # Remove last event just for cleanliness
          BlockingInput.pop(self, -1)
  
          # This will exit even if not in infinite mode.  This is
          # consistent with MATLAB and sometimes quite useful, but will
          # require the user to test how many points were actually
          # returned before using data.
          self.fig.canvas.stop_event_loop()
  
      def mouse_event_pop(self, event):
          """
          Will be called for any event involving button 3.
          Button 3 removes the last click.
          """
          # Remove this last event
          BlockingInput.pop(self, -1)
  
          # Now remove any existing clicks if possible
          if len(self.events) > 0:
              self.pop(event, -1)
  
      def add_click(self, event):
          """
          This add the coordinates of an event to the list of clicks
          """
          self.clicks.append((event.xdata, event.ydata))
  
          verbose.report("input %i: %f,%f" %
                         (len(self.clicks), event.xdata, event.ydata))
  
          # If desired plot up click
          if self.show_clicks:
              line = mlines.Line2D([event.xdata], [event.ydata],
                                   marker='+', color='r')
              event.inaxes.add_line(line)
              self.marks.append(line)
              self.fig.canvas.draw()
  
      def pop_click(self, event, index=-1):
          """
          This removes a click from the list of clicks.  Defaults to
          removing the last click.
          """
          self.clicks.pop(index)
  
          if self.show_clicks:
  
              mark = self.marks.pop(index)
              mark.remove()
  
              self.fig.canvas.draw()
              # NOTE: I do NOT understand why the above 3 lines does not work
              # for the keyboard backspace event on windows XP wxAgg.
              # maybe event.inaxes here is a COPY of the actual axes?
  
      def pop(self, event, index=-1):
          """
          This removes a click and the associated event from the object.
          Defaults to removing the last click, but any index can be
          supplied.
          """
          self.pop_click(event, index)
          BlockingInput.pop(self, index)
  
      def cleanup(self, event=None):
          # clean the figure
          if self.show_clicks:
  
              for mark in self.marks:
                  mark.remove()
              self.marks = []
  
              self.fig.canvas.draw()
  
          # Call base class to remove callbacks
          BlockingInput.cleanup(self)
  
      def __call__(self, n=1, timeout=30, show_clicks=True):
          """
          Blocking call to retrieve n coordinate pairs through mouse
          clicks.
          """
          self.show_clicks = show_clicks
          self.clicks = []
          self.marks = []
          BlockingInput.__call__(self, n=n, timeout=timeout)
  
          return self.clicks
  
  
  class BlockingContourLabeler(BlockingMouseInput):
      """
      Class that creates a callable object that uses mouse clicks or key
      clicks on a figure window to place contour labels.
      """
      def __init__(self, cs):
          self.cs = cs
          BlockingMouseInput.__init__(self, fig=cs.ax.figure)
  
      def add_click(self, event):
          self.button1(event)
  
      def pop_click(self, event, index=-1):
          self.button3(event)
  
      def button1(self, event):
          """
          This will be called if an event involving a button other than
          2 or 3 occcurs.  This will add a label to a contour.
          """
  
          # Shorthand
          if event.inaxes == self.cs.ax:
              self.cs.add_label_near(event.x, event.y, self.inline,
                                     inline_spacing=self.inline_spacing,
                                     transform=False)
              self.fig.canvas.draw()
          else:  # Remove event if not valid
              BlockingInput.pop(self)
  
      def button3(self, event):
          """
          This will be called if button 3 is clicked.  This will remove
          a label if not in inline mode.  Unfortunately, if one is doing
          inline labels, then there is currently no way to fix the
          broken contour - once humpty-dumpty is broken, he can't be put
          back together.  In inline mode, this does nothing.
          """
  
          if self.inline:
              pass
          else:
              self.cs.pop_label()
              self.cs.ax.figure.canvas.draw()
  
      def __call__(self, inline, inline_spacing=5, n=-1, timeout=-1):
          self.inline = inline
          self.inline_spacing = inline_spacing
  
          BlockingMouseInput.__call__(self, n=n, timeout=timeout,
                                      show_clicks=False)
  
  
  class BlockingKeyMouseInput(BlockingInput):
      """
      Class that creates a callable object to retrieve a single mouse or
      keyboard click
      """
      def __init__(self, fig):
          BlockingInput.__init__(self, fig=fig, eventslist=(
              'button_press_event', 'key_press_event'))
  
      def post_event(self):
          """
          Determines if it is a key event
          """
          assert len(self.events) > 0, "No events yet"
  
          self.keyormouse = self.events[-1].name == 'key_press_event'
  
      def __call__(self, timeout=30):
          """
          Blocking call to retrieve a single mouse or key click
          Returns True if key click, False if mouse, or None if timeout
          """
          self.keyormouse = None
          BlockingInput.__call__(self, n=1, timeout=timeout)
  
          return self.keyormouse
  