Matplotlib equivalent of pygame flip

Question

I have a program with rapid animations which works perfectly under pygame, and for technical reasons, I need to do the same using only matplotlib or an other widespread module.

The program structure is roughly:

pygame.init()        
SURF = pygame.display.set_mode((500, 500))
arr = pygame.surfarray.pixels2d(SURF) # a view for numpy, as a 2D array
while ok:
    # modify some pixels of arr
    pygame.display.flip()
pygame.quit()

I have no low level matplotlib experience, but I think it is possible to do equivalent things with matplotlib. In other words :

How to share the bitmap of a figure, modify some pixels and refresh the screen ?

Here is a minimal working exemple, which flips 250 frames per second (more than the screen ...) on my computer :

import pygame,numpy,time
pygame.init()
size=(400,400)        
SURF = pygame.display.set_mode(size)
arr = pygame.surfarray.pixels2d(SURF) # buffer pour numpy   
t0=time.clock()

for counter in range(1000):
        arr[:]=numpy.random.randint(0,0xfffff,size)
        pygame.display.flip()      
pygame.quit()

print(counter/(time.clock()-t0))

EDIT

What I try with indications in answers :

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation

fig = plt.figure()


def f(x, y):
    return np.sin(x) + np.cos(y)

x = np.linspace(0, 2 * np.pi, 400)
y = np.linspace(0, 2 * np.pi, 400).reshape(-1, 1)

im = plt.imshow(f(x, y), animated=True)

count=0
t0=time.clock()+1
def updatefig(*args):
    global x, y,count,t0
    x += np.pi / 15.
    y += np.pi / 20.
    im.set_array(f(x, y))
    if time.clock()<t0:
        count+=1
    else:
        print (count)
        count=0
        t0=time.clock()+1     
    return im,

ani = animation.FuncAnimation(fig, updatefig, interval=50, blit=True)
plt.show()

But this only provides 20 fps....

Answer 1

It should be noted that the human brain is capable of "seeing" up to a framerate of ~25 fps. Faster updates are not actually resolved.

Matplotlib

With matplotlib and its animation module the example from the question runs with 84 fps on my computer.

import time
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation

fig, ax = plt.subplots()


def f(x, y):
    return np.sin(x) + np.cos(y)

x = np.linspace(0, 2 * np.pi, 400)
y = np.linspace(0, 2 * np.pi, 400).reshape(-1, 1)

im = ax.imshow(f(x, y), animated=True)
text = ax.text(200,200, "")

class FPS():
    def __init__(self, avg=10):
        self.fps = np.empty(avg)
        self.t0 = time.clock()
    def tick(self):
        t = time.clock()
        self.fps[1:] = self.fps[:-1]
        self.fps[0] = 1./(t-self.t0)
        self.t0 = t
        return self.fps.mean()

fps = FPS(100)

def updatefig(i):
    global x, y
    x += np.pi / 15.
    y += np.pi / 20.
    im.set_array(f(x, y))
    tx = 'Mean Frame Rate:\n {fps:.3f}FPS'.format(fps= fps.tick() ) 
    text.set_text(tx)     
    return im, text,

ani = animation.FuncAnimation(fig, updatefig, interval=1, blit=True)
plt.show()

PyQtGraph

In pyqtgraph a higher framerate is obtained, it would run with 295 fps on my computer.

import sys
import time
from pyqtgraph.Qt import QtCore, QtGui
import numpy as np
import pyqtgraph as pg

class FPS():
    def __init__(self, avg=10):
        self.fps = np.empty(avg)
        self.t0 = time.clock()
    def tick(self):
        t = time.clock()
        self.fps[1:] = self.fps[:-1]
        self.fps[0] = 1./(t-self.t0)
        self.t0 = t
        return self.fps.mean()

fps = FPS(100)

class App(QtGui.QMainWindow):
    def __init__(self, parent=None):
        super(App, self).__init__(parent)

        #### Create Gui Elements ###########
        self.mainbox = QtGui.QWidget()
        self.setCentralWidget(self.mainbox)
        self.mainbox.setLayout(QtGui.QVBoxLayout())

        self.canvas = pg.GraphicsLayoutWidget()
        self.mainbox.layout().addWidget(self.canvas)

        self.label = QtGui.QLabel()
        self.mainbox.layout().addWidget(self.label)

        self.view = self.canvas.addViewBox()
        self.view.setAspectLocked(True)
        self.view.setRange(QtCore.QRectF(0,0, 100, 100))

        #  image plot
        self.img = pg.ImageItem(border='w')
        self.view.addItem(self.img)

        #### Set Data  #####################
        self.x = np.linspace(0, 2 * np.pi, 400)
        self.y = np.linspace(0, 2 * np.pi, 400).reshape(-1, 1)

        #### Start  #####################
        self._update()
        
    def f(self, x, y):
            return np.sin(x) + np.cos(y)
        
    def _update(self):

        self.x += np.pi / 15.
        self.y += np.pi / 20.
        self.img.setImage(self.f(self.x, self.y))

        tx = 'Mean Frame Rate:\n {fps:.3f}FPS'.format(fps= fps.tick() ) 
        self.label.setText(tx)
        QtCore.QTimer.singleShot(1, self._update)


if __name__ == '__main__':

    app = QtGui.QApplication(sys.argv)
    thisapp = App()
    thisapp.show()
    sys.exit(app.exec_())