# 사각형 그리기 예제
import numpy as np
import cv2
from matplotlib import pyplot as plt

blue, green, red = (0, 0, 255), (0, 255, 0), (255, 0, 0)
image = np.zeros((400, 600, 3), np.uint8)  # 3채널 영상
image[:] = 255 # 3채널 흰색

pt1, pt2 = (50, 50), (250, 150)
pt3, pt4 = (400, 150), (500, 50) 
roi = (50, 200, 200, 100) # 사각형 영역 = 4원소 튜플

cv2.rectangle(image, pt1, pt2, red, 3, cv2.LINE_4) # 4방향 연결선
cv2.rectangle(image, roi, blue, 3, cv2.LINE_8) # 8방향 연결선
cv2.rectangle(image, (400, 200, 100, 100), green, cv2.FILLED) # 내부채움

plt.imshow(image)
plt.show()

cv2.rectangle(image, pt1, pt2, blue, 3, cv2.LINE_4) # 4방향 연결선
cv2.rectangle(image, roi, red, 9, cv2.LINE_8) # 8방향 연결선
cv2.rectangle(image, (400, 200, 100, 100), green, cv2.FILLED) # 내부채움

plt.imshow(image)
plt.show()

import cv2
from matplotlib import pyplot as plt

cv2.rectangle(image, pt1, pt2, blue, 9, cv2.LINE_4) # 4방향 연결선
cv2.rectangle(image, roi, red, 9, cv2.LINE_8) # 8방향 연결선
cv2.rectangle(image, (400, 200, 100, 100), green, cv2.FILLED) # 내부채움

plt.imshow(image)
plt.show()

cv2.rectangle(image, pt1, pt2, blue, 3, cv2.LINE_4) # 4방향 연결선
cv2.rectangle(image, roi, red, 9, cv2.LINE_8) # 8방향 연결선
cv2.rectangle(image, (400, 100, 100, 100), green, cv2.FILLED) # 내부채움

plt.imshow(image)
plt.show()

import numpy as np, cv2
from matplotlib import pyplot as plt

# 이미지 생성
image = np.zeros((500, 500, 3), dtype=np.uint8)
image[ : ] = 255

# 사각형 그리기
cv2.rectangle(image, (50, 50), (450, 450), (255, 0, 0), 9, cv2.LINE_4)
cv2.rectangle(image, (70, 70), (430, 430), (0, 255, 0), 9, cv2.LINE_8)
cv2.rectangle(image, (90, 90), (410, 410), (0, 0, 255), 9, cv2.LINE_AA)

# 결과 보기
plt.imshow( image )
plt.show()