Python-OpenCV 杂项(二): 鼠标事件

0x00. 查看鼠标事件

下面的方法可以查看OpenCV支持的所有鼠标事件:

import cv2
events=[i for i in dir(cv2) if 'EVENT'in i]
print events

输出结果:

['EVENT_FLAG_ALTKEY', 'EVENT_FLAG_CTRLKEY', 'EVENT_FLAG_LBUTTON', 'EVENT_FLAG_MBUTTON', 'EVENT_FLAG_RBUTTON', 'EVENT_FLAG_SHIFTKEY', 'EVENT_LBUTTONDBLCLK', 'EVENT_LBUTTONDOWN', 'EVENT_LBUTTONUP', 'EVENT_MBUTTONDBLCLK', 'EVENT_MBUTTONDOWN', 'EVENT_MBUTTONUP', 'EVENT_MOUSEMOVE', 'EVENT_RBUTTONDBLCLK', 'EVENT_RBUTTONDOWN', 'EVENT_RBUTTONUP']

0x01. 使用示例:

下面代码实现鼠标移动绘制图像:

import cv2
import numpy as np
def draw_circle(event,x,y,flags,param):
  if event==cv2.EVENT_MOUSEMOVE:
    cv2.circle(img,(x,y),100,(255,0,0),-1)

img = np.zeros((512,512,3),np.uint8)
cv2.namedWindow('image')
cv2.setMouseCallback('image',draw_circle)

while(1):
  cv2.imshow('image',img)
  if cv2.waitKey(20)&0xFF==27:
    break
cv2.destroyAllWindows()

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