OpenCV之鼠标操作绘制图形

#coding=utf-8

import cv2
import numpy as np
# 全局变量
drawing = False  # 是否开始绘制
mode = 'none'  # 当前绘制模式
start_x, start_y = -1, -1  # 绘制起点坐标

# 鼠标回调函数
def draw_shape(event, x, y, flags, param):
    global drawing, start_x, start_y, mode

    if (event & cv2.EVENT_LBUTTONDOWN == cv2.EVENT_LBUTTONDOWN):
        drawing = True
        start_x, start_y = x, y

    elif (event & cv2.EVENT_LBUTTONUP == cv2.EVENT_LBUTTONUP):
        drawing = False
        if mode == 'rectangle':
            cv2.rectangle(img, (start_x, start_y), (x, y), (0, 255, 0), 2)
            print("矩形坐标：", (start_x, start_y), (x, y))
        elif mode == 'circle':
            radius = int(((x - start_x)**2 + (y - start_y)**2)**0.5)
            cv2.circle(img, (start_x, start_y), radius, (0, 0, 255), 2)
            print("圆形坐标：", (start_x, start_y), "半径：", radius)
        elif mode == 'line':
            cv2.line(img, (start_x, start_y), (x, y), (255, 0, 0), 2)
            print("直线坐标：", (start_x, start_y), (x, y))
# 创建空白图像
img = np.zeros((512, 512, 3), np.uint8)

# 创建窗口并绑定鼠标回调函数
cv2.namedWindow('Drawing', cv2.WINDOW_NORMAL)
cv2.setMouseCallback('Drawing', draw_shape)

# 显示绘制界面，按下键盘按键来绘制图形
while True:
    cv2.imshow('Drawing', img)
    key = cv2.waitKey(1) & 0xFF

    if key == ord('r'):
        mode = 'rectangle'
    elif key == ord('c'):
        mode = 'circle'
    elif key == ord('l'):
        mode = 'line'
    elif key == 27 or key == ord('q'):  # 按下 ESC 键退出
        break

cv2.destroyAllWindows()