Matplotlib动画:使用blit时，第一帧保留在画布中 [英] Matplotlib animation: first frame remains in canvas when using blit

问题描述

我正在尝试使用Matplotlib动画库绘制两个旋转椭圆，并且设法使其工作(或多或少).问题在于正在渲染的第一帧不会更新，因此当我在画布中有两个旋转椭圆形时，我也将椭圆形保留为其原始位置/方向.看看我的简单代码:

I'm trying to plot two rotating ellipses using the Matplotlib animation library, and I managed to get it working (more or less). The problem is that the first frame that is being rendered does not update, so while I got two rotating ellipses in my canvas, I also have the ellipses in their original position/orientation. Check out my simple piece of code:

import matplotlib.pyplot as plt
from matplotlib.patches import Ellipse
from matplotlib import animation

fig = plt.figure()
ax = fig.add_subplot(111, aspect='equal')
e1 = Ellipse(xy=(0.5, 0.5), width=0.5, height=0.2, angle=60)
e2 = Ellipse(xy=(0.8, 0.8), width=0.5, height=0.2, angle=100)

def init():
    ax.add_patch(e1)
    ax.add_patch(e2)
    return [e1,e2]

def animate(i):
    e1.angle = e1.angle + 0.5
    e2.angle = e2.angle + 0.5
    return [e1,e2]

anim = animation.FuncAnimation(fig, animate, init_func=init, interval=1, blit=True)
plt.show()

有什么办法解决这个问题吗?我当然可以关闭blit，但这会使它变得非常慢，因此这不是一个真正的选择.

Any idea how to fix this? I could of course turn off blit, but that makes it horribly slow, so that's not really an option.

最终(有效)代码

import matplotlib.pyplot as plt
from matplotlib.patches import Ellipse
from matplotlib import animation

fig = plt.figure()
ax = fig.add_subplot(111, aspect='equal')
e1 = Ellipse(xy=(0.5, 0.5), width=0.5, height=0.2, angle=60)
e2 = Ellipse(xy=(0.8, 0.8), width=0.5, height=0.2, angle=100)
ax.add_patch(e1)
ax.add_patch(e2)

def init():
    e1.set_visible(False)
    e2.set_visible(False)
    return [e1,e2]

def animate(i):
    if i == 1:
        e1.set_visible(True)
        e2.set_visible(True)
    e1.angle = e1.angle + 0.5
    e2.angle = e2.angle + 0.5
    return [e1,e2]

anim = animation.FuncAnimation(fig, animate, init_func=init, interval=1, blit=True)
plt.show()

推荐答案

尝试一下:

import matplotlib.pyplot as plt
from matplotlib.patches import Ellipse
from matplotlib import animation

fig = plt.figure()
ax = fig.add_subplot(111, aspect='equal')
e1 = Ellipse(xy=(0.5, 0.5), width=0.5, height=0.2, angle=60)
e2 = Ellipse(xy=(0.8, 0.8), width=0.5, height=0.2, angle=100)


def init():
    return [ax]

def animate(i):
    if i==0:
        ax.add_patch(e1)
        ax.add_patch(e2)    
    e1.angle = e1.angle + 0.5
    e2.angle = e2.angle + 0.5
    return [e1,e2]

anim = animation.FuncAnimation(fig, animate, init_func=init, interval=1, blit=True)
plt.show()

尝试另一种方法(不是我仅使用一个椭圆进行测试，在这里也可以正常渲染):

Try this other approach (not I've used only one ellipse just for testing, it also renders fine here):

import matplotlib.pyplot as plt
from matplotlib.patches import Ellipse
from matplotlib import animation

fig = plt.figure()
ax = fig.add_subplot(111, aspect='equal')
e1 = Ellipse(xy=(0.5, 0.5), width=0.5, height=0.2, angle=60)
ax.add_patch(e1)

def init():
    e1.set_visible(False)
    return e1,

def animate(i):
    if i==0:
        e1.set_visible(True)
    e1.angle = e1.angle + 0.5
    return e1,

anim = animation.FuncAnimation(fig, animate, init_func=init, interval=1, blit=True)
plt.show()

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