.. _old_animation-animation_blit_qt4:

old_animation example code: animation_blit_qt4.py
=================================================

[`source code <animation_blit_qt4.py>`_]

::

    # For detailed comments on animation and the techniqes used here, see
    # the wiki entry http://www.scipy.org/Cookbook/Matplotlib/Animations
    
    from __future__ import print_function
    
    import os
    import sys
    
    #import matplotlib
    #matplotlib.use('Qt4Agg')
    from matplotlib.figure import Figure
    from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
    
    from PyQt4 import QtCore, QtGui
    
    ITERS = 1000
    
    import numpy as np
    import time
    
    class BlitQT(FigureCanvas):
    
        def __init__(self):
            FigureCanvas.__init__(self, Figure())
    
            self.ax = self.figure.add_subplot(111)
            self.ax.grid()
            self.draw()
    
            self.old_size = self.ax.bbox.width, self.ax.bbox.height
            self.ax_background = self.copy_from_bbox(self.ax.bbox)
            self.cnt = 0
    
            self.x = np.arange(0,2*np.pi,0.01)
            self.sin_line, = self.ax.plot(self.x, np.sin(self.x), animated=True)
            self.cos_line, = self.ax.plot(self.x, np.cos(self.x), animated=True)
            self.draw()
    
            self.tstart = time.time()
            self.startTimer(10)
    
        def timerEvent(self, evt):
            current_size = self.ax.bbox.width, self.ax.bbox.height
            if self.old_size != current_size:
                self.old_size = current_size
                self.ax.clear()
                self.ax.grid()
                self.draw()
                self.ax_background = self.copy_from_bbox(self.ax.bbox)
    
            self.restore_region(self.ax_background)
    
            # update the data
            self.sin_line.set_ydata(np.sin(self.x+self.cnt/10.0))
            self.cos_line.set_ydata(np.cos(self.x+self.cnt/10.0))
            # just draw the animated artist
            self.ax.draw_artist(self.sin_line)
            self.ax.draw_artist(self.cos_line)
            # just redraw the axes rectangle
            self.blit(self.ax.bbox)
    
            if self.cnt == 0:
                # TODO: this shouldn't be necessary, but if it is excluded the
                # canvas outside the axes is not initially painted.
                self.draw()
            if self.cnt==ITERS:
                # print the timing info and quit
                print('FPS:' , ITERS/(time.time()-self.tstart))
                sys.exit()
            else:
                self.cnt += 1
    
    app = QtGui.QApplication(sys.argv)
    widget = BlitQT()
    widget.show()
    
    sys.exit(app.exec_())
    

Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)