Matplotlib相当于pygame翻转 [英] Matplotlib equivalent of pygame flip

问题描述

我有一个带有快速动画的程序，可以在pygame下完美运行，并且由于技术原因，我只需要使用matplotlib或其他广泛使用的模块来做同样的事情.

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.

程序结构大致为:

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()

我没有低级的matplotlib经验，但是我认为使用matplotlib可以做等效的事情.换句话说:

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

如何共享图形的位图，修改一些像素并刷新屏幕?

这是一个最小的工作示例，它在我的计算机上每秒翻转250帧(比屏幕还多……):

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))

编辑

我尝试使用答案中的指示:

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()

但这只能提供20 fps....

But this only provides 20 fps....

推荐答案

应注意，人脑能够看到"高达25 fps的帧速率.更快的更新实际上并没有解决.

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.

使用matplotlib及其animation模块，问题示例在计算机上以 84 fps 运行.

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

在pyqtgraph中获得更高的帧速率，它将在我的计算机上以 295 fps 运行.

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_())

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