雨滴，美丽的雨滴

原程序是别人的，我只是加了GIF录制。

# -*- coding: utf-8 -*-
"""
Created on Sat Jun  3 13:17:50 2017

@author: jiangyl
"""

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

# New figure with white background
fig = plt.figure(figsize=(6,6), facecolor='white')

# New axis over the whole figure, no frame and a 1:1 aspect ratio
ax = fig.add_axes([0, 0, 1, 1], frameon=False, aspect=1)

# Number of ring
n = 50
size_min = 50
size_max = 50 ** 2

# Ring position
pos = np.random.uniform(0, 1, (n,2))

# Ring colors
color = np.ones((n,4)) * (0,0,0,1)
# Alpha color channel geos from 0(transparent) to 1(opaque)
color[:,3] = np.linspace(0, 1, n)

# Ring sizes
size = np.linspace(size_min, size_max, n)

# Scatter plot
scat = ax.scatter(pos[:,0], pos[:,1], s=size, lw=0.5, edgecolors=color, facecolors='None')

# Ensure limits are [0,1] and remove ticks
ax.set_xlim(0, 1), ax.set_xticks([])
ax.set_ylim(0, 1), ax.set_yticks([])

def update(frame):
    global pos, color, size

    # Every ring is made more transparnt
    color[:, 3] = np.maximum(0, color[:,3]-1.0/n)

    # Each ring is made larger
    size += (size_max - size_min) / n

    # Reset specific ring
    i = frame % 50
    pos[i] = np.random.uniform(0, 1, 2)
    size[i] = size_min
    color[i, 3] = 1

    # Update scatter object
    scat.set_edgecolors(color)
    scat.set_sizes(size)
    scat.set_offsets(pos)

    # Return the modified object
    return scat,

anim = animation.FuncAnimation(fig, update, interval=30, blit=True, frames=80)
anim.save('snow.gif', fps=30, writer='imagemagick')
print("ok")
plt.show()

要使用IMAGEMAGICK需安装插件，我试了一下，用最新版的制作GIF不成功，用6.9.8的就可以。

链接见：

http://www.imagemagick.org/download/binaries/