OpenCV Series : Target Box Outline Border

角点

P1      [0]     (255, 000, 000)
P2      [1]     (000, 255, 000)
P3      [2]     (000, 000, 255)
P4      [3]     (000, 000, 000)

垂直矩形框

	rect = cv2.minAreaRect(cnt)
	targetColor = roi_color
	targetThickness = 1
	targetColor = (255, 255, 255)
	if lineVerbose:
		if True:
		   cv2.line(photo,  (x, y), (x+w//4, y), targetColor, targetThickness)
		   cv2.line(photo,  (x, y), (x, y+h//4), targetColor, targetThickness)
		
		   cv2.line(photo,  (x+3*w//4, y), (x+w, y), targetColor, targetThickness)
		   cv2.line(photo,  (x+w, y), (x+w, y+h//4), targetColor, targetThickness)
		
		   cv2.line(photo,  (x, y+h), (x+w//4, y+h), targetColor, targetThickness)
		   cv2.line(photo,  (x, y+h), (x, y+3*h//4), targetColor, targetThickness)
		
		   cv2.line(photo,  (x+w, y+h), (x+3*w//4, y+h), targetColor, targetThickness)
		   cv2.line(photo,  (x+w, y+h), (x+w, y+3*h//4), targetColor, targetThickness)
		
		   crossLength = 15
		   cv2.line(photo,  (x+w//2-crossLength, y+h//2), (x+w//2+crossLength, y+h//2), targetColor, targetThickness)
		   cv2.line(photo,  (x+w//2, y+h//2-crossLength), (x+w//2, y+h//2+crossLength), targetColor, targetThickness)

倾斜矩形框

def lineByAngle(photo, p1, p2, length, color, thickness):
    slope = 0 + (p2[1] - p1[1]) / (p2[0] - p1[0])
    theta = np.arctan(slope)
    degree = int(theta * 57.29577) % 360

    length = getDistance(p1, p2) // 4

    if (p2[0] < p1[0]):
        pp = (
            int(p1[0] - length * np.cos(theta)),
            int(p1[1] - length * np.sin(theta))
        )
    else:
        pp = (
            int(p1[0] + length * np.cos(theta)),
            int(p1[1] + length * np.sin(theta))
        )
    cv2.line(photo,  p1, pp, color, thickness)