如何阻止matplotlib GUI线程冻结？

Question

from matplotlib import pyplot as p 
from scipy import zeros 
from Queue import Queue 
import random 

w,h = 320,200 

black = zeros((h,w,3), dtype='uint8') 
red = black.copy(); red[:,:,0] = 255 
green = black.copy(); green[:,:,1] = 255 
blue = black.copy(); blue[:,:,2] = 255 

def ants(): 
    from scipy import rand, dstack 
    return dstack([(255*rand(h,w)).astype('uint8')]*3) 

fig = p.figure() 
axs = [fig.add_subplot(1,3,i) for i in xrange(3)] 
[ax.imshow(black) for ax in axs] 

q = Queue() 

def update_image(ax): 
    ## this takes some time 
    import time 
    time.sleep(3) 
    ax.images[0].set_data(random.choice([red, green, blue])) 

def hit(event): 
    if event.inaxes in axs: 
    update_axs = [event.inaxes] 
    else: 
    update_axs = axs 
    for ax in update_axs: 
    ax.images[0].set_data(ants()) 
    p.draw() 
# for ax in update_axs: 
# update_image(ax) 
# p.draw() 

cid = fig.canvas.mpl_connect('button_press_event', hit) 
p.show() 

这里是我的代码，其中所有的按预期工作。然而，当我取消注释事件处理程序中的这3行时，有一些问题我没有想到。首先GUI冻结，而update_image正在工作，其次第一个电话draw()似乎没有机会画，因为我没有看到赛车蚂蚁，而update_image正在工作。在matplotlib中设置这种类型的东西的更好的方法是什么？

Answer 1

为避免冻结GUI，您需要在单独的线程或进程中运行update_image。使用threading，你可能会做这样的事情：

import matplotlib 
matplotlib.use('TkAgg') 
from matplotlib import pyplot as p 
from scipy import zeros 
import random 
import threading 


w,h = 320,200 

black = zeros((h,w,3), dtype='uint8') 
red = black.copy(); red[:,:,0] = 255 
green = black.copy(); green[:,:,1] = 255 
blue = black.copy(); blue[:,:,2] = 255 

def ants(): 
    from scipy import rand, dstack 
    return dstack([(255*rand(h,w)).astype('uint8')]*3) 

fig = p.figure() 
axs = [fig.add_subplot(1,3,i) for i in xrange(3)] 
[ax.imshow(black) for ax in axs] 

def update_image(ax): 
    ## this takes some time 
    import time 
    time.sleep(3) 
    ax.images[0].set_data(random.choice([red, green, blue])) 
    ax.figure.canvas.draw() 

def hit(event): 
    if event.inaxes in axs: 
     update_axs = [event.inaxes] 
    else: 
     update_axs = axs 
    for ax in update_axs: 
     ax.images[0].set_data(ants()) 
    p.draw() 
    for ax in update_axs: 
     t=threading.Thread(target=update_image,args=(ax,)) 
     t.daemon=True 
     t.start() 

cid = fig.canvas.mpl_connect('button_press_event', hit) 
p.show()