OpenCV-Python 鼠标绘图

参考

• Mouse as a Paint-Brush

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代码

import cv2
import numpy as np

drawing = False # 鼠标左键按下时，该值为True，标记正在绘画
mode = True # True 画矩形，False 画圆
ix, iy = -1, -1 # 鼠标左键按下时的坐标


def draw_circle(event, x, y, flags, param):
    global ix, iy, drawing, mode

    if event == cv2.EVENT_LBUTTONDOWN:
        # 鼠标左键按下事件
        drawing = True
        ix, iy = x, y

    elif event == cv2.EVENT_MOUSEMOVE:
        # 鼠标移动事件
        if drawing == True:
            if mode == True:
                cv2.rectangle(img, (ix, iy), (x, y), (0, 255, 0), -1)
            else:
                cv2.circle(img, (x, y), 5, (0, 0, 255), -1)

    elif event == cv2.EVENT_LBUTTONUP:
        # 鼠标左键松开事件
        drawing = False
        if mode == True:
            cv2.rectangle(img, (ix, iy), (x, y), (0, 255, 0), -1)
        else:
            cv2.circle(img, (x, y), 5, (0, 0, 255), -1)


img = np.zeros((512, 512, 3), np.uint8)
cv2.namedWindow('image')
cv2.setMouseCallback('image', draw_circle) # 设置鼠标事件的回调函数

while(1):
    cv2.imshow('image', img)
    k = cv2.waitKey(1) & 0xFF
    if k == ord('m'):
        mode = not mode
    elif k == 27:
        break

cv2.destroyAllWindows()

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效果