我一直在使用opencv并已通过cv2.setMouseCallback()。以下是鼠标单击时绘制圆圈的代码。 导入cv2导入numpy为np
def draw_circle(event,x,y,flags,param):
if event == cv2.EVENT_LBUTTONDBLCLK:
cv2.circle(image,(x,y),(100,100),(255,0,0),-1)
img = np.zeros((512,512,3), np.uint8)
cv2.namedWindow("image")
cv2.setMouseCallback("image",draw_circle)
while True:
cv2.imshow("image",image)
if cv2.waitKey(1) & 0xFF == ord("q"):
break
cv2.destroyAllWindows()`
请解释
谢谢!
draw_circle
,openCV将在具有正确事件和坐标的鼠标事件上为你调用它,你只需指定在setMouseCallback
中为哪个窗口调用哪个函数param
发送我希望这个例子对于偶然发现的人有所帮助:
import cv2
import numpy as np
from math import sqrt
def calc_distance(p1, p2):
(x1, y1) = p1
(x2, y2) = p2
return round(sqrt((x1-x2)**2 + (y1-y2)**2))
# param contains the center and the color of the circle
def draw_red_circle(event, x, y, flags, param):
if event == cv2.EVENT_LBUTTONDBLCLK:
center = param[0]
radius = calc_distance((x, y), center)
cv2.circle(img, center, radius, param[1], 2)
def draw_blue_circle(event, x, y, flags, param):
if event == cv2.EVENT_LBUTTONDBLCLK:
center = (100,100)
radius = calc_distance((x, y), center)
cv2.circle(img, center, radius, (255, 0, 0), 2)
img = np.zeros((512,512,3), np.uint8)
# create 2 windows
cv2.namedWindow("img_red")
cv2.namedWindow("img_blue")
# different doubleClick action for each window
# you can send center and color to draw_red_circle via param
param = [(200,200),(0,0,255)]
cv2.setMouseCallback("img_red", draw_red_circle, param)
cv2.setMouseCallback("img_blue", draw_blue_circle) # param = None
while True:
# both windows are displaying the same img
cv2.imshow("img_red", img)
cv2.imshow("img_blue", img)
if cv2.waitKey(1) & 0xFF == ord("q"):
break
cv2.destroyAllWindows()