def on_key_event(self, event):
     if event.key == 'a':
         ax = event.inaxes
         ax.set_autoscalex_on(True)
         ax.set_autoscaley_on(True)
     else:
         key_press_handler(event, self.canvas, self.toolbar)

 def on_key_press(self, event):
     #绑定键盘事件到画布和工具栏
     key_press_handler(event, self.canvas, self.toolbar)
     if event.key == "enter":
         self.data.get_homo()
     elif event.key == "N":
         self.emit(QtCore.SIGNAL("play_next()"))

 def on_key_event(self, event):
     print('you pressed %s'%event.key)
     key_press_handler(event, self.canvas, self.toolbar)
     if event.key in ['q','escape']: # Use (some) unassigned buttons to quit
         print('--> Program quit')
         self.root.quit()
         self.root.destroy()  # this is necessary on Windows to prevent

        def on_key_press(self, event):
            from matplotlib.backend_bases import key_press_handler

            print("you pressed", event.key)
            # implement the default mpl key press events described at
            # http://matplotlib.org/users/navigation_toolbar.html
            key_press_handler(event, self.canvas, self.mpl_toolbar)

    def on_key_event(self, event):
        """

        @param event:
        @return
        """
        print('you pressed %s' % event.key)
        key_press_handler(event, self.canvas, self.toolbar)

 def on_key_press(self, event):
     print('Plot pressed', event.key)
     # implement the default mpl key press events described at
     # http://matplotlib.org/users/navigation_toolbar.html#navigation-keyboard-shortcuts
     try:
         key_press_handler(event, self.canvas, self.mpl_toolbar)
     except:
         pass

    def on_key_press(self, event):
        # sometimes mpl has a weird ideas what oo-programing is.
        # any could overwrite method by my self

        # no fullscreen unless self is a window!
        if event.key == "t":
            self.toolbar.toggle()
        elif event.key not in rcParams["keymap.fullscreen"]:
            key_press_handler(event, self.canvas, self.toolbar)

 def on_key_press(self, event):
     if event.key == 'a' or event.key == "alt+a" and event.inaxes:
         ax = event.inaxes
         ax.relim()
         l = 1.1*max(abs(ax.dataLim.y0), abs(ax.dataLim.y1))
         ax.set_ylim(-l,l)
         ax.figure.canvas.draw()
     else:
         key_press_handler(event, event.canvas, self.toolbar)

 def on_key_press(self, event):
     # print 'Matplotlib-> you pressed:' + str(event.key)
     # implement the default mpl key press events described at
     # http://matplotlib.org/users/navigation_toolbar.html#navigation-
     # keyboard-shortcuts
     try:
         from matplotlib.backend_bases import key_press_handler
         key_press_handler(event, self.canvas, self.mpl_toolbar)
     except:
         print("key_press_handler import failed. -old matplotlib version.")

    def on_key_press(self, event):
        key_press_handler(event, self.canvas, self.mpl_toolbar)

        if event.key == 'a':
            command = commands.AddIonsToTable([self._picked_ion], self._analyses_model)
            self._undo_stack.push(command)

        if event.key == 'r':
            command = commands.AddIonsToTable([self._picked_ion], self._analyses_model)
            self._undo_stack.push(command)
            command = commands.SelectMethod(self._picked_ion, 'Manual', self._analyses_model, self._methods_view_model)
            self._undo_stack.push(command)

            self._span_selector = SpanSelector(self.ax,self.on_span_select,'horizontal', minspan=0.0001, span_stays=True, rectprops=dict(alpha=0.5))
            QApplication.setOverrideCursor(QCursor(Qt.IBeamCursor))

 def canvas_key_press(self, event):
     key_press_handler(event, self.canvas, self.mpl_toolbar)
     if event.key == 'ctrl+q':
         self._close()
     elif event.key in mpl.rcParams['keymap.home']:
         self.xlim = self.ylim = None
         self.draw()
     elif event.key == 'ctrl+x':
         self.set_xlim(draw=False)
     elif event.key == 'ctrl+y':
         self.set_ylim(draw=False)
     elif event.key == 'ctrl+l':
         self.draw()
     self.xlogscale = self.axes.get_xscale()
     self.ylogscale = self.axes.get_yscale()

def on_key_event(event):
    #Flecha de abajo
    if event.key==D:
        global state
        global a
        global b
        global x 
        x = x
        if state==5:
            state=0
        else:
            state=state+1
        graficar(x)
    #Flecha de arriba
    elif event.key==U:
        global state
        global a
        global b
        global x 
        x = x
        if state==0:
            state=5
        else:
            state=state-1
        graficar(x)
    #Flecha derecha
    elif event.key==R:
        global a
        global b
        global x 
        if x>=700:
            x=700
        else:
            x = x + 10
        graficar(x)
    #Flecha Izquierda
    elif event.key==L:
        global a
        global b
        global x 
        if x<=200:
            x=200
        else:
            x = x - 10
        graficar(x)
    else:
        pass
    key_press_handler(event, canvas, toolbar)

 def keyPressEvent(self, event):
     """ Catch key events so that they can be passed on to the matplotlib
     toolbar. """
     try:
         key_press_handler(event, self.canvas, self.toolbar)
     except AttributeError:
         # Attribute errors seem to occur when a key is pressed while the
         # mouse is outside of the figure area:
         #
         # AttributeError: 'QKeyEvent' object has no attribute 'inaxes'
         #
         # This exception may be safely ignored.
         pass
     except Exception as e:
         print(e)
         raise e

		def tracer_key_handler( self, event ) :

			if event.key == 'p' or event.key == ' ' :
				self.pause()
			elif event.key == 'b' :
				self.band()
			elif event.key == 'd' :
				self.save_data()
			elif event.key == 'a' :
				event.inaxes.abscissa.set_visible( not event.inaxes.abscissa.get_visible() )
				self.canvas.draw()
			else :
				try :
					key_press_handler( event, self.canvas, self )
				except NameError :
					pass

 def on_key(self,event):
     """to change scale from linear to logaritm
     Home/Reset	                        h or r or home
     Back	                            c or left arrow or backspace
     Forward	                            v or right arrow
     Pan/Zoom	                        p
     Zoom-to-rect	                    o
     Save	                            ctrl + s
     Toggle fullscreen	                ctrl + f
     Close plot	                        ctrl + w
     Constrain pan/zoom to x axis	    hold x when panning/zooming with mouse
     Constrain pan/zoom to y axis	    hold y when panning/zooming with mouse
     Preserve aspect ratio	            hold CONTROL when panning/zooming with mouse
     Toggle grid	g                       when mouse is over an axes
     Toggle x axis scale (log/linear)	L or k when mouse is over an axes
     Toggle y axis scale (log/linear)	l when mouse is over an axes
     """
     key_press_handler(event, self.canvas, self.toolbar)  

 def on_key_press(self, event):
     '''
                         当按下回车键，计算一个H;按下SHift+n，处理下一副图像
     '''
     key_press_handler(event, self.canvas, self.toolBar)# 绑定mpl按键到画布和工具栏
     if event.key is "enter":
         # 计算H
         if self.data.nCorner > 2:
             print("Compute H...")
             self.data.solve_homography()
             #print(self.data.nCorner + 1, self.data.corners)
         else:
             print("Not enough corners!")
         # 初始化单应的角点列表数据
         self.data.init_corners()
         print(">>> click the cross point on same circle OR play next image.")
     elif event.key is "N":
         print(event.key)
         self.emit(QtCore.SIGNAL("play_next()"))

def on_key_press(event):

    #Matplotlib Toolbar keybindings:
    key_press_handler(event, canvas, toolbar)

 def on_key_event(event):    
     print 'event is ', event
     key_press_handler(event, canvas, toolbar)        

def on_key_event(event):
    key_press_handler(event, canvas, toolbar)

def on_key_press(event):
    print("you pressed {}".format(event.key))
    key_press_handler(event, canvas, toolbar)