matplotlib & pandas

Python/matplotlab/gallery/animation/rain.md

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+# 雨模拟
+
+通过设置50个散点的比例和不透明度来模拟表面上的雨滴。
+
+作者：Nicolas P. Rougier
+
+![雨模拟示例](https://matplotlib.org/_images/sphx_glr_rain_001.png)
+
+```python
+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 = plt.figure(figsize=(7, 7))
+ax = fig.add_axes([0, 0, 1, 1], frameon=False)
+ax.set_xlim(0, 1), ax.set_xticks([])
+ax.set_ylim(0, 1), ax.set_yticks([])
+
+# Create rain data
+n_drops = 50
+rain_drops = np.zeros(n_drops, dtype=[('position', float, 2),
+                                      ('size',     float, 1),
+                                      ('growth',   float, 1),
+                                      ('color',    float, 4)])
+
+# Initialize the raindrops in random positions and with
+# random growth rates.
+rain_drops['position'] = np.random.uniform(0, 1, (n_drops, 2))
+rain_drops['growth'] = np.random.uniform(50, 200, n_drops)
+
+# Construct the scatter which we will update during animation
+# as the raindrops develop.
+scat = ax.scatter(rain_drops['position'][:, 0], rain_drops['position'][:, 1],
+                  s=rain_drops['size'], lw=0.5, edgecolors=rain_drops['color'],
+                  facecolors='none')
+
+
+def update(frame_number):
+    # Get an index which we can use to re-spawn the oldest raindrop.
+    current_index = frame_number % n_drops
+
+    # Make all colors more transparent as time progresses.
+    rain_drops['color'][:, 3] -= 1.0/len(rain_drops)
+    rain_drops['color'][:, 3] = np.clip(rain_drops['color'][:, 3], 0, 1)
+
+    # Make all circles bigger.
+    rain_drops['size'] += rain_drops['growth']
+
+    # Pick a new position for oldest rain drop, resetting its size,
+    # color and growth factor.
+    rain_drops['position'][current_index] = np.random.uniform(0, 1, 2)
+    rain_drops['size'][current_index] = 5
+    rain_drops['color'][current_index] = (0, 0, 0, 1)
+    rain_drops['growth'][current_index] = np.random.uniform(50, 200)
+
+    # Update the scatter collection, with the new colors, sizes and positions.
+    scat.set_edgecolors(rain_drops['color'])
+    scat.set_sizes(rain_drops['size'])
+    scat.set_offsets(rain_drops['position'])
+
+
+# Construct the animation, using the update function as the animation director.
+animation = FuncAnimation(fig, update, interval=10)
+plt.show()
+```
+
+## 下载这个示例
+            
+- [下载python源码: rain.py](https://matplotlib.org/_downloads/rain.py)
+- [下载Jupyter notebook: rain.ipynb](https://matplotlib.org/_downloads/rain.ipynb)