如何在Python中画一个只能在对角线内裁剪的圆

发布于03月07日

我正试着画一个被对角线截断的圆.以下是我的不起作用的代码:

import matplotlib.pyplot as plt

# Create the circle with radius 6
circle = plt.Circle((0, 0), 6, color='r', fill=False)

# Set up the plot (reuse the previous grid settings)
plt.figure(figsize=(8, 8))
plt.xlim(0, 10)
plt.ylim(0, 10)
plt.grid()

# Add the circle to the plot
ax = plt.gca()
ax.add_patch(circle)

# Draw a diagonal line
plt.plot([0, 7], [7, 0], color='b', linestyle='--')

# Set aspect ratio to ensure square grid cells
ax.set_aspect("equal")

# Clip the circle using the diagonal line.
# This doesn't work
ax.set_clip_path(plt.Polygon([[0, 0], [7, 0], [0, 7]]))

# Show the plot
plt.title("Circle Centered at (0,0) (not) Clipped by Diagonal Line")
plt.show()

以下是它目前显示的内容.

我不想显示任何超过对角线的圆.

推荐答案

创建多边形时设置transform，并用circle.set_clip_path(polygon)剪裁圆.举个例子:

import matplotlib.pyplot as plt

# Create the circle with radius 6
circle = plt.Circle((0, 0), 6, color='r', fill=False)

# Set up the plot (reuse the previous grid settings)
plt.figure(figsize=(8, 8))
plt.xlim(0, 10)
plt.ylim(0, 10)
plt.grid()

# Add the circle to the plot
ax = plt.gca()
ax.add_patch(circle)

# Draw a diagonal line
plt.plot([0, 7], [7, 0], color='b', linestyle='--')

# Set aspect ratio to ensure square grid cells
ax.set_aspect("equal")

polygon = plt.Polygon([[0, 0], [7, 0], [0, 7]], transform=ax.transData)

# Clip the circle using the diagonal line.
circle.set_clip_path(polygon)

# Show the plot
plt.title("Circle Centered at (0,0) Clipped by Diagonal Line")
plt.show()

结果: