将背景图像绘制到matplotlib图形

Question

我正在尝试绘制一个简单的线条图并将背景图像插入到图中.

示例pic(使用cat.jpg和dog.jpd):

目前我有一个代码绘制线条(来自熊猫数据帧)并将图像放入图中.然而,图像和线图根本不会"相互作用".

fig, ax = plt.subplots(figsize=(15,10))
cat = np.array(Image.open('cat.jpg'))
dog = np.array(Image.open('dog.jpg'))
ax.imshow(cat, extent=[0, 10, 0, 18], aspect='auto',   cmap='gray',alpha=0.75)
ax.imshow(dog, extent=[10, 20, 0, 18], aspect='auto', cmap='gray',alpha=0.75)

ax.plot(df['Series'],color='#3cb8fb',alpha=0.95,linewidth=3.0)

plt.show()

Answer 1

您可以使用plt.fill_between创建覆盖原点和线之间区域的多边形,然后使用.set_clip_path每个图像对象的方法仅显示位于多边形内的图像部分.

例如:

from matplotlib import pyplot as plt
from scipy.misc import lena

fig, ax = plt.subplots(1, 1)

x = np.linspace(0, 1, 10)
y = np.random.rand(10)
image = ax.imshow(lena(), cmap=plt.cm.gray, extent=[0, 1, 0, 1])
line = ax.plot(x, y, '-r', lw=2)

# invisible clipping polygon
poly = ax.fill_between(x, 0, y, visible=False)
clip = poly.get_paths()[0]

# you will need to do this separately for each of the images in your plot
image.set_clip_path(clip, transform=ax.transData)

plt.show()