Python绘制动画示例

照猫画虎，首先看看Python matpotlib官网http://matplotlib.org/examples/index.html上的示例都完成了什么功能，毕竟自己研究API太费时

1、



import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation

def data_gen(t=0):
cnt = 0
while cnt < 1000:
cnt += 1
t += 0.1
yield t, np.sin(2*np.pi*t) * np.exp(-t/10.)

def init():
ax.set_ylim(-1.1, 1.1)
ax.set_xlim(0, 10)
del xdata[:]
del ydata[:]
line.set_data(xdata, ydata)
return line,

fig, ax = plt.subplots()
line, = ax.plot([], [], lw=2)
ax.grid()
xdata, ydata = [], []

def run(data):
# update the data
t, y = data
xdata.append(t)
ydata.append(y)
xmin, xmax = ax.get_xlim()

if t >= xmax:
ax.set_xlim(xmin, 2*xmax)
ax.figure.canvas.draw()
line.set_data(xdata, ydata)

return line,

ani = animation.FuncAnimation(fig, run, data_gen, blit=False, interval=10,
repeat=False, init_func=init)
plt.show()

2、

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation

fig = plt.figure()

def f(x, y):
return np.sin(x) + np.cos(y)

x = np.linspace(0, 2 * np.pi, 120)
y = np.linspace(0, 2 * np.pi, 100).reshape(-1, 1)

im = plt.imshow(f(x, y), animated=True)

def updatefig(*args):
global x, y
x += np.pi / 15.
y += np.pi / 20.
im.set_array(f(x, y))
return im,

ani = animation.FuncAnimation(fig, updatefig, interval=50, blit=True)
plt.show()

3、





import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation

def update_line(num, data, line):
line.set_data(data[..., :num])
return line,

fig1 = plt.figure()

data = np.random.rand(2, 25)
l, = plt.plot([], [], 'r-')
plt.xlim(0, 1)
plt.ylim(0, 1)
plt.xlabel('x')
plt.title('test')
line_ani = animation.FuncAnimation(fig1, update_line, 25, fargs=(data, l),
interval=50, blit=True)

# To save the animation, use the command: line_ani.save('lines.mp4')

fig2 = plt.figure()

x = np.arange(-9, 10)
y = np.arange(-9, 10).reshape(-1, 1)
base = np.hypot(x, y)
ims = []
for add in np.arange(15):
ims.append((plt.pcolor(x, y, base + add, norm=plt.Normalize(0, 30)),))

im_ani = animation.ArtistAnimation(fig2, ims, interval=50, repeat_delay=3000,
blit=True)
# To save this second animation with some metadata, use the following command:
# im_ani.save('im.mp4', metadata={'artist':'Guido'})

plt.show()

4、

import numpy as np

import matplotlib.pyplot as plt
import matplotlib.patches as patches
import matplotlib.path as path
import matplotlib.animation as animation

fig, ax = plt.subplots()

# histogram our data with numpy
data = np.random.randn(1000)
n, bins = np.histogram(data, 100)

# get the corners of the rectangles for the histogram
left = np.array(bins[:-1])
right = np.array(bins[1:])
bottom = np.zeros(len(left))
top = bottom + n
nrects = len(left)

# here comes the tricky part -- we have to set up the vertex and path
# codes arrays using moveto, lineto and closepoly

# for each rect: 1 for the MOVETO, 3 for the LINETO, 1 for the
# CLOSEPOLY; the vert for the closepoly is ignored but we still need
# it to keep the codes aligned with the vertices
nverts = nrects*(1 + 3 + 1)
verts = np.zeros((nverts, 2))
codes = np.ones(nverts, int) * path.Path.LINETO
codes[0::5] = path.Path.MOVETO
codes[4::5] = path.Path.CLOSEPOLY
verts[0::5, 0] = left
verts[0::5, 1] = bottom
verts[1::5, 0] = left
verts[1::5, 1] = top
verts[2::5, 0] = right
verts[2::5, 1] = top
verts[3::5, 0] = right
verts[3::5, 1] = bottom

barpath = path.Path(verts, codes)
patch = patches.PathPatch(
barpath, facecolor='green', edgecolor='yellow', alpha=0.5)
ax.add_patch(patch)

ax.set_xlim(left[0], right[-1])
ax.set_ylim(bottom.min(), top.max())

def animate(i):
# simulate new data coming in
data = np.random.randn(1000)
n, bins = np.histogram(data, 100)
top = bottom + n
verts[1::5, 1] = top
verts[2::5, 1] = top
return [patch, ]

ani = animation.FuncAnimation(fig, animate, 100, repeat=False, blit=True)
plt.show()

5、将动画保存视频文件，先安装 sudo apt-get
install ffmpeg
import numpy as np
import matplotlib
matplotlib.use("Agg")
import matplotlib.pyplot as plt
import matplotlib.animation as animation

def update_line(num, data, line):
line.set_data(data[..., :num])
return line,

# Set up formatting for the movie files
Writer = animation.writers['ffmpeg']
writer = Writer(fps=15, metadata=dict(artist='Me'), bitrate=1800)

fig1 = plt.figure()

data = np.random.rand(2, 25)
l, = plt.plot([], [], 'r-')
plt.xlim(0, 1)
plt.ylim(0, 1)
plt.xlabel('x')
plt.title('test')
line_ani = animation.FuncAnimation(fig1, update_line, 25, fargs=(data, l),
interval=50, blit=True)
FFwriter = animation.FFMpegWriter()
line_ani.save('basic_animation.mp4', writer = FFwriter, fps=30, extra_args=['-vcodec', 'libx264'])
#line_ani.save('lines.mp4', writer=writer)

fig2 = plt.figure()

x = np.arange(-9, 10)
y = np.arange(-9, 10).reshape(-1, 1)
base = np.hypot(x, y)
ims = []
for add in np.arange(15):
ims.append((plt.pcolor(x, y, base + add, norm=plt.Normalize(0, 30)),))

im_ani = animation.ArtistAnimation(fig2, ims, interval=50, repeat_delay=3000,
blit=True)
#im_ani.save('im.mp4', writer=writer)