如何为子图绘制动画图例? [英] How to draw animated legend for subplots?

问题描述

我想用ArtistAnimation绘制动画子图.不幸的是，我无法弄清楚如何制作动画图例.我尝试了在StackOverflow上找到的其他方法.如果我设法得到一个图例，则它不是动画的，而是所有动画的图例同时出现.

I would like to draw animated subplots with ArtistAnimation. Unfortunately, I cannot figure out how to have an animated legend. I tried out different methods I found on StackOverflow. If I manage to get a legend it is not animated, but just the legends of all animation steps together.

我的代码如下:

import numpy as np
import pylab as pl
import matplotlib.animation as anim

fig, (ax1, ax2, ax3) = pl.subplots(1,3,figsize=(11,4))
ims   = []
im1   = ['im11','im12','im13']
im2   = ['im21','im22','im23']
x = np.arange(0,2*np.pi,0.1)

n=50
for i in range(n):
    for sp in (1,2,3):
        pl.subplot(1,3,sp)

        y1 = np.sin(sp*x + i*np.pi/n)
        y2 = np.cos(sp*x + i*np.pi/n)

        im1[sp-1], = pl.plot(x,y1)
        im2[sp-1], = pl.plot(x,y2)

        pl.xlim([0,2*np.pi])
        pl.ylim([-1,1])

        lab = 'i='+str(i)+', sp='+str(sp)
        im1[sp-1].set_label([lab])
        pl.legend(loc=2, prop={'size': 6}).draw_frame(False)

    ims.append([ im1[0],im1[1],im1[2], im2[0],im2[1],im2[2] ])

ani = anim.ArtistAnimation(fig,ims,blit=True)
pl.show()

我认为这段代码将等同于此处使用的方法如何在python动画中添加图例/标签，但显然我丢失了一些内容.

I thought this code would be equivalent to the method used here How to add legend/label in python animation but obviously I am missing something.

我还尝试按照

I also tried to set the labels as suggested in Add a legend for an animation (of Artists) in matplotlib but I do not really understand how to use it for my case. Like this

im2[sp-1].legend(handles='-', labels=[lab])

我得到一个AttributeError: 'Line2D' object has no attribute 'legend'.

:我并没有明确指出:我希望在图中的两条线都有一个图例.

: I did not state it clearly: I would like to have a legend for both lines in the plots.

推荐答案

我不知道图例应该是什么样子，但我想想您只想让它显示当前帧.因此，您最好更新该行的数据，而不是绘制150个新图.

I do not know what exactly the legend should look like, but I'd imaginge you simply want to let it display the current value of the one line from the current frame. You'd therefore better update the data of the line, instead of plotting 150 new plots.

import numpy as np
import pylab as plt
import matplotlib.animation as anim

fig, axes = plt.subplots(1,3,figsize=(8,3))
ims   = []
im1   = [ax.plot([],[], label="label")[0] for ax in axes]
im2   = [ax.plot([],[], label="label")[0] for ax in axes]
x = np.arange(0,2*np.pi,0.1)

legs = [ax.legend(loc=2, prop={'size': 6})  for ax in axes]

for ax in axes:
    ax.set_xlim([0,2*np.pi])
    ax.set_ylim([-1,1])
plt.tight_layout()
n=50
def update(i):
    for sp in range(3):
        y1 = np.sin((sp+1)*x + (i)*np.pi/n)
        y2 = np.cos((sp+1)*x + (i)*np.pi/n)

        im1[sp].set_data(x,y1)
        im2[sp].set_data(x,y2)

        lab = 'i='+str(i)+', sp='+str(sp+1)
        legs[sp].texts[0].set_text(lab)
        legs[sp].texts[1].set_text(lab)

    return im1 + im2 +legs 

ani = anim.FuncAnimation(fig,update, frames=n,blit=True)
plt.show()

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