python 鼠标实时画矩形

opencv python

根据官方文档实现python cv2 鼠标事件 

但是画出的矩形是填充的，并不是轮廓

修改下代码只显示鼠标弹起的坐标大小。

import cv2

import numpyas np

drawing =False  # true if mouse is pressed

mode =True  # if True, draw rectangle. Press 'm' to toggle to curve

ix, iy = -1, -1

# mouse callback function

def draw_circle(event, x, y, flags, param):

global ix, iy, drawing, mode

# print(flags)

    if event == cv2.EVENT_LBUTTONDOWN:

drawing =True

        ix, iy = x, y

elif event == cv2.EVENT_MOUSEMOVE:

if drawing ==True:

if mode ==True:

# pass

                tmp=img.copy()

cv2.rectangle(tmp, (ix, iy), (x, y), (0, 255, 0), 1)

cv2.imshow('image', tmp)

else:

cv2.circle(img, (x, y), 5, (0, 0, 255), -1)

elif event == cv2.EVENT_LBUTTONUP:

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)

cv2.imshow('image', img)

while (1):

k = cv2.waitKey(1) &0xFF

    if k ==ord('m'):

mode =not mode

elif k ==27:

break

cv2.destroyAllWindows()