使用Matplotlib保存Python动态图像为视频文件的方法与技巧

FuncAnimation类

class matplotlib.animation.FuncAnimation(

fig, func, frames&＃61;None, init_func&＃61;None,

fargs&＃61;None, save_count&＃61;None, **kwargs)

参数

fig : matplotlib.figure.Figure对象&＃xff0c;可以理解为画布

func : 函数(callable)&＃xff0c;每一帧被调用一次

函数签名大概是这样的&＃xff1a;def func(frame, *fargs) -> iterable_of_artists

第一个参数是frames中的元素&＃xff0c;第二个是fargs参数设置的附件参数

返回值是可迭代的图形对象

frames : 可迭代对象, 整数, 生成函数或者None&＃xff0c;传递给动画函数func的帧

如果是可迭代对象&＃xff0c;可迭代对象的长度将覆盖save_count参数

如果是个整数&＃xff0c;值就是range(frames)

如果是生成函数&＃xff0c;签名必须是def gen_function() -> obj:

如果是None,frames&＃61;itertools.count&＃xff0c;相当于整数从0开始步长1无限迭代

init_func : 函数(callable)

用来画一个完整的帧&＃xff0c;如果没有给&＃xff0c;使用的是frames中的第一个元素&＃xff0c;在第一帧之前被调用

如果If blit &＃61;&＃61; True, init_func 必须返回一个可迭代的图形对象

签名像&＃xff1a;def init_func() -> iterable_of_artists:

fargs : 元组或None&＃xff0c;每一次调用func的附加参数

save_count : 整数&＃xff0c;缓存的帧的数量

interval : number, 2帧之间的延迟&＃xff0c;默认200毫秒

repeat_delay : number, 重复延迟&＃xff0c;默认None

repeat : bool, 是否重复&＃xff0c;默认True

blit : bool, 是否使用blitting优化&＃xff0c;默认False

blitting的含义是内存中图像的位块传输&＃xff0c;指的是将某一表面的全部或部分图像复制到另一表面上

动图存储配置

# print matplotlib.matplotlib_fname()

# matplotlib\mpl-data\matplotlibrc

animation.writer : ffmpeg ## MovieWriter 使用

animation.ffmpeg_path: ffmpeg ## 可执行文件ffmpeg路径&＃xff0c;会搜索$PATH

animation.convert_path: magick ## 可执行文件magick路径&＃xff0c;会搜索$PATH

animation.convert_args: convert ## 执行magick的附件参数&＃xff0c;因为新ImageMagick的没有convert命令了&＃xff0c;所以使用的是convert参数

要保存动图和视频需要使用ImageMagick&＃xff0c;后面有下载链接&＃xff0c;下载安装之后的目录大概如下&＃xff1a;

下载页面&＃xff1a;

sin实例

# -*- coding:utf-8 -*-

import numpy as np

from matplotlib import pyplot as plt

from matplotlib import animation

import matplotlib

# print matplotlib.matplotlib_fname()

fig &＃61; plt.figure()

ax &＃61; plt.axes(xlim&＃61;(0, 2), ylim&＃61;(-2, 2))

line, &＃61; ax.plot([], [], lw&＃61;2)

def init():

line.set_data([], [])

return line,

def animate(i):

#linespace(起始值(start),终止值(stop),数量(num)&＃61;50,是否包含终止值(endpoint)&＃61;True,是否返回步长(retstep)&＃61;False,数据类型(dtype)&＃61;None)

x &＃61; np.linspace(0, 2, 1000)

y &＃61; np.sin(2 * np.pi * (x - 0.01 * i))

line.set_data(x, y)

return line,

anim &＃61; animation.FuncAnimation(fig, animate, init_func&＃61;init,frames&＃61;200, interval&＃61;20, blit&＃61;True)

anim.save(&＃39;sin.gif&＃39;, fps&＃61;75, writer&＃61;&＃39;imagemagick&＃39;)

plt.show()

circle实例

# -*- coding:utf-8 -*-

import numpy as np

import matplotlib.pyplot as plt

import matplotlib.animation as animation

import matplotlib.path as mpath

import matplotlib.patches as mpatch

from matplotlib.patches import Circle

import random

fig,ax &＃61; plt.subplots()

ax.set_xticks([])

ax.set_yticks([])

ax.spines["left"].set_color("none")

ax.spines["top"].set_color("none")

ax.spines["right"].set_color("none")

ax.spines["bottom"].set_color("none")

ax.axis([-5,5,-5,5])

# ax.add_patch(mpatch.PathPatch(mpath.Path.circle()))

circle &＃61; Circle(xy &＃61; (0.0, 0.0), radius&＃61;0.5, alpha&＃61;0.5)

ax.add_patch(circle)

def init():

return Circle(xy &＃61; (0.0, 0.0), radius&＃61;0.5, alpha&＃61;0.5),

def animate(i):

circle.set_radius(i*0.5)

circle.set_facecolor(random.choice("rmcky"))

return circle,

# fig &＃61; plt.gcf()

# fg &＃61; range(1,11)

# fgr &＃61; range(1,11)

# fgr.reverse()

# fs &＃61; fg &＃43; fgr

fs &＃61; [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1]

ani &＃61; animation.FuncAnimation(fig, animate, init_func&＃61;init,frames&＃61;fs,interval&＃61;1000, blit&＃61;True)

# ani &＃61; animation.FuncAnimation(fig, animate, frames&＃61;360, init_func&＃61;init, interval&＃61;0.1, blit&＃61;True, save_count&＃61;50)

# ani &＃61; animation.FuncAnimation(fig, animate, frames&＃61;10, init_func&＃61;init, interval&＃61;0.1, blit&＃61;True, save_count&＃61;50,repeat&＃61;False)

ani.save(&＃39;circle.gif&＃39;, fps&＃61;2, writer&＃61;&＃39;imagemagick&＃39;)

plt.show()

rain实例

# -*- coding:utf-8 -*-

import numpy as np

import matplotlib.pyplot as plt

from matplotlib.animation import FuncAnimation

# Fixing random state for reproducibility

np.random.seed(19680801)

# Create new Figure and an Axes which fills it.

fig &＃61; plt.figure(figsize&＃61;(7, 7))

ax &＃61; fig.add_axes([0, 0, 1, 1], frameon&＃61;False)

ax.set_xlim(0, 1), ax.set_xticks([])

ax.set_ylim(0, 1), ax.set_yticks([])

# Create rain data

n_drops &＃61; 50

rain_drops &＃61; np.zeros(n_drops, dtype&＃61;[(&＃39;position&＃39;, float, 2),

(&＃39;size&＃39;, float, 1),

(&＃39;growth&＃39;, float, 1),

(&＃39;color&＃39;, float, 4)])

# Initialize the raindrops in random positions and with

# random growth rates.

rain_drops[&＃39;position&＃39;] &＃61; np.random.uniform(0, 1, (n_drops, 2))

rain_drops[&＃39;growth&＃39;] &＃61; np.random.uniform(50, 200, n_drops)

# Construct the scatter which we will update during animation

# as the raindrops develop.

scat &＃61; ax.scatter(rain_drops[&＃39;position&＃39;][:, 0], rain_drops[&＃39;position&＃39;][:, 1],

s&＃61;rain_drops[&＃39;size&＃39;], lw&＃61;0.5, edgecolors&＃61;rain_drops[&＃39;color&＃39;],

facecolors&＃61;&＃39;none&＃39;)

def update(frame_number):

# Get an index which we can use to re-spawn the oldest raindrop.

current_index &＃61; frame_number % n_drops

# Make all colors more transparent as time progresses.

rain_drops[&＃39;color&＃39;][:, 3] -&＃61; 1.0/len(rain_drops)

rain_drops[&＃39;color&＃39;][:, 3] &＃61; np.clip(rain_drops[&＃39;color&＃39;][:, 3], 0, 1)

# Make all circles bigger.

rain_drops[&＃39;size&＃39;] &＃43;&＃61; rain_drops[&＃39;growth&＃39;]

# Pick a new position for oldest rain drop, resetting its size,

# color and growth factor.

rain_drops[&＃39;position&＃39;][current_index] &＃61; np.random.uniform(0, 1, 2)

rain_drops[&＃39;size&＃39;][current_index] &＃61; 5

rain_drops[&＃39;color&＃39;][current_index] &＃61; (0, 0, 0, 1)

rain_drops[&＃39;growth&＃39;][current_index] &＃61; np.random.uniform(50, 200)

# Update the scatter collection, with the new colors, sizes and positions.

scat.set_edgecolors(rain_drops[&＃39;color&＃39;])

scat.set_sizes(rain_drops[&＃39;size&＃39;])

scat.set_offsets(rain_drops[&＃39;position&＃39;])

# Construct the animation, using the update function as the animation director.

animation &＃61; FuncAnimation(fig, update, interval&＃61;10)

animation.save(&＃39;rain.gif&＃39;, fps&＃61;75, writer&＃61;&＃39;imagemagick&＃39;)

plt.show()

保存为mp4

# -*- coding:utf-8 -*-

import numpy as np

import matplotlib

matplotlib.use("Agg")

import matplotlib.pyplot as plt

from matplotlib.animation import FFMpegWriter

# Fixing random state for reproducibility

np.random.seed(19680801)

metadata &＃61; dict(title&＃61;&＃39;Movie Test&＃39;, artist&＃61;&＃39;Matplotlib&＃39;,comment&＃61;&＃39;Movie support!&＃39;)

writer &＃61; FFMpegWriter(fps&＃61;15, metadata&＃61;metadata)

fig &＃61; plt.figure()

l, &＃61; plt.plot([], [], &＃39;k-o&＃39;)

plt.xlim(-5, 5)

plt.ylim(-5, 5)

x0, y0 &＃61; 0, 0

with writer.saving(fig, "writer_test.mp4", 100):

for i in range(100):

x0 &＃43;&＃61; 0.1 * np.random.randn()

y0 &＃43;&＃61; 0.1 * np.random.randn()

l.set_data(x0, y0)

writer.grab_frame()

画心型mp4

# -*- coding:utf-8 -*-

import numpy as np

import matplotlib

matplotlib.use("Agg")

import matplotlib.pyplot as plt

from matplotlib.animation import FFMpegWriter

import math

metadata &＃61; dict(title&＃61;&＃39;heart&＃39;, artist&＃61;&＃39;Matplotlib&＃39;,comment&＃61;&＃39;draw heart&＃39;)

writer &＃61; FFMpegWriter(fps&＃61;15, metadata&＃61;metadata)

figure &＃61; plt.figure()

axes &＃61; plt.gca()

axes.set_xticks([])

axes.set_yticks([])

axes.spines["left"].set_color("none")

axes.spines["top"].set_color("none")

axes.spines["right"].set_color("none")

axes.spines["bottom"].set_color("none")

line1, &＃61; axes.plot([], [], color&＃61;&＃39;red&＃39;, linewidth&＃61;2,)

line2, &＃61; axes.plot([], [], color&＃61;&＃39;red&＃39;, linewidth&＃61;2,)

plt.xlim(-5, 5)

plt.ylim(-5, 5)

x0, y0 &＃61; 0, 0

with writer.saving(figure, "heart.mp4", 100):

for i in range(15):

t &＃61; np.linspace(0, i/math.pi, 100)

x &＃61; np.sin(t)

y &＃61; np.cos(t) &＃43; np.power(x, 2.0/3)

line1.set_data(x, y)

line2.set_data(-x, y)

writer.grab_frame()

视频没有办法上传&＃xff0c;如果感兴趣可以自己尝试一下。

参考