# 用Python实现流星雨效果的方法详解

`matplotlib`并不能给一条曲线映射多个颜色，故而可将一条线拆分成多条，效果如图所示

```import numpy as np
import matplotlib.pyplot as plt
from matplotlib.collections import LineCollection

x0,y0 = 1,1     #此为流星位置
ts = np.arange(0,1,0.01)    #参数
xs,ys = x0+ts, y0+ts        #绘图线条

points = np.array([xs, ys]).T.reshape(-1, 1, 2)
segments = np.concatenate([points[:-1], points[1:]], axis=1)

ax = plt.subplot()
lc = LineCollection(segments, cmap="viridis")

lc.set_array(ts)
lc.set_linewidth(ts[::-1])

ax.set_xlim(0, 3)
ax.set_ylim(0, 3)
plt.show()
```

```from numpy.random import rand, randint
N,L = 20,100  #流星个数和线段数
ts = np.array([
np.linspace(0,rand(),L) for _ in range(N)]).T
x0,y0 = rand(2*N).reshape(2,1,N)
x0 *= 5
xs,ys = x0+ts, y0+ts #绘图线条1

points = np.array([xs, ys]).T.reshape(N,L,-1,2)

ax = plt.subplot()
for i in range(N):
segs = np.concatenate([points[i][:-1], points[i][1:]], axis=1)
lc = LineCollection(segs, cmap="viridis")
lc.set_array(ts[:,i])
lc.set_linewidth(ts[::-1,i])

ax.set_xlim(0, 6)
ax.set_ylim(-2, 3)
ax.set_axis_off()                      #取消坐标轴
plt.show()
```

```plt.figure(facecolor="black")          #将背景设为黑色
```

```lc = LineCollection(segs, cmap="viridis_r")
```