matplotlib 动画，文本不更新

Question

我是使用 Matplotlib 制作动画的新手，遇到了一些麻烦。我想创建一个粒子位置的动画，我想在每一步显示帧号。我在代码 sn-p 的开头创建了示例数据，因此代码是独立的（通常我的数据是从 csv 读取的）。

问题 - 显示的绘图完全空白。但是，如果我注释掉 time_text 的返回（即将“返回补丁，time_text”更改为“返回补丁”）一切正常。我认为问题在于我如何更新 time_text，但我不知道如何修复它。

---

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

您需要让您的初始化函数返回pyplot.text 对象。您还应该在每次调用 anim 函数时启动要修改的对象。

看看ArtistAnimation，它可能更适合你的工作。

为了避免画布上聚集很多圆圈，我宁愿更新路径对象的位置，而不是在每次迭代时添加新的。

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()