matplotlib動畫，文本沒有更新

Question

我是新來的動畫與Matplotlib，並有一點麻煩。我想創建一個粒子位置的動畫，並且我想在每一步顯示幀編號。我在代碼片段的開頭創建了示例數據，所以代碼是自包含的（通常我的數據是從csv讀入的）。

問題 - 顯示的圖是完全空白的。但是，如果我將time_text的返回註釋掉（即將「返回修補程序，time_text」更改爲「返回修補程序」），則一切正常。我認爲問題在於我如何更新time_text，但我堅持如何解決它。

---

from matplotlib import pyplot as plt 
from matplotlib import animation 
import numpy as np 
import pandas as pd 

box_size = 50 
radius = 1 

df =pd.DataFrame(np.array([np.arange(50),np.arange(50),np.arange(50)]).T, 
          columns = ['x','y','frame']) 

#set up the figure 
fig = plt.figure() 
plt.axis([0,box_size,0,box_size]) 
ax = plt.gca() 
ax.set_aspect(1) 
time_text = ax.text(5, 5,'') 

#initialization of animation, plot empty array of patches 
def init(): 
    time_text.set_text('initial') 
    return [] 

def animate(i): 
    patches = [] 
    #data for this frame only 
    data = df[df.frame == i] 
    time_text.set_text('frame'+str(i)) 
    #plot circles at particle positions 
    for idx,row in data.iterrows(): 
     patches.append(ax.add_patch(plt.Circle((row.x,row.y),radius,color= 'b', 
               alpha = 0.5)))    
    return patches, time_text 

anim = animation.FuncAnimation(fig, animate, init_func=init, repeat = False, 
           frames=int(df.frame.max()), interval=50, 
           blit=True) 

Answer 1

你需要讓你的初始化函數返回pyplot.text對象。您還應該在anim函數的每個調用中啓動要修改的對象。

看看ArtistAnimation，它可能更適合你在做什麼。

爲了避免許多圓圈聚集在畫布上，我寧願更新路徑對象的位置，而不是在每次迭代時追加新的路徑對象。

from matplotlib import pyplot as plt 
import matplotlib.patches as patches 
from matplotlib import animation 
import numpy as np 
import pandas as pd 

box_size = 50 
radius = 1 

df = pd.DataFrame(np.array([np.arange(50),np.arange(50),np.arange(50)]).T, 
          columns = ['x','y','frame']) 

#set up the figure 
fig = plt.figure() 
plt.axis([0,box_size,0,box_size]) 
ax = plt.gca() 
time_text = ax.text(5, 5,'') 

circle = plt.Circle((1.0,1.0), radius,color='b', alpha=0.5, facecolor='orange', lw=2) 


#initialization of animation, plot empty array of patches 
def init(): 
    time_text.set_text('initial') 
    ax.add_patch(circle) 
    return time_text, ax 

def animate(i): 
    #data for this frame only 
    data = df[df.frame == i] 
    time_text.set_text('frame' + str(i)) 

    #plot circles at particle positions 
    for idx,row in data.iterrows(): 
     circle.center = row.x,row.y 

    return time_text, ax 

anim = animation.FuncAnimation(fig, animate, init_func=init, repeat = False, 
           frames=int(df.frame.max()), interval=200, blit=True) 

plt.show()