画方入圆

Question

我想在圆中画内切方，但我不知道，我应该如何计算起点和终点：

import numpy as np
import cv2

img = np.zeros([300,300,3],dtype=np.uint8)
img.fill(255) # or img[:] = 255

imageWithCircle = cv2.circle(img, (150,150), 60, (0, 0, 255), 2)

#startpoint = ...
#endpoint = ...

imageWithInscribingSquare = cv2.rectangle(imageWithCircle, startpoint, endpoint, (0, 0, 255) , 2)

cv2.imshow("Circle", imageWithCircle)
cv2.waitKey(0)
cv2.destroyAllWindows()

Answer 1

检查这个：

import numpy as np
import cv2

img = np.zeros([300,300,3],dtype=np.uint8)
img.fill(255) # or img[:] = 255

imageWithCircle = cv2.circle(img, (150,150), 60, (0, 0, 255), 2)

r = 60
startpoint = (int(150+(r/(2**0.5))),int(150-(r/(2**0.5))))
endpoint = (int(150-(r/(2**0.5))),int(150+(r/(2**0.5))))

print(startpoint,print(endpoint))


imageWithInscribingSquare = cv2.rectangle(imageWithCircle, startpoint, endpoint, (255, 0, 0) , 2)

cv2.imshow("Circle", imageWithCircle)
cv2.waitKey(0)
cv2.destroyAllWindows()

输出：

计算：

如果半径为'r'，则正方形的边长为√2r，从中心开始点的宽度减少√2r/2，高度增加√2r/2，端点反之亦然。

画方入圆

Draw inscribe square into the circle

python

drawing