如何使用OpenCV和Python在变量中保存鼠标位置？

Question

我正在使用Python和OpenCV进行一些视觉应用.我需要在变量中保存鼠标位置,我不知道如何.我可以将当​​前鼠标位置打印到窗口中,但不能将其保存到变量中.

我的问题类似于这个只有我在python中工作: OpenCV从鼠标回调函数返回值

我这样定义我的函数(用于打印鼠标位置):

def mousePosition(event,x,y,flags,param):
    if event == cv2.EVENT_MOUSEMOVE:
        print x,y

我在我的程序中使用它,如下所示:

cv2.setMouseCallback('Drawing spline',mousePosition)

Answer 1

以下是代码的小修改版本:http://docs.opencv.org/trunk/doc/py_tutorials/py_gui/py_mouse_handling/py_mouse_handling.html#mouse-handling

import cv2
import numpy as np

ix,iy = -1,-1
# mouse callback function
def draw_circle(event,x,y,flags,param):
    global ix,iy
    if event == cv2.EVENT_LBUTTONDBLCLK:
        cv2.circle(img,(x,y),100,(255,0,0),-1)
        ix,iy = x,y

# Create a black image, a window and bind the function to window
img = np.zeros((512,512,3), np.uint8)
cv2.namedWindow('image')
cv2.setMouseCallback('image',draw_circle)

while(1):
    cv2.imshow('image',img)
    k = cv2.waitKey(20) & 0xFF
    if k == 27:
        break
    elif k == ord('a'):
        print ix,iy
cv2.destroyAllWindows()

它将鼠标位置存储在全局变量中ix,iy.每次双击时,它都会将值更改为新位置.按a可打印新值.

Answer 2

创建一个小类并将坐标添加为成员可以避免全局变量。

import cv2
import numpy as np  



class CoordinateStore:
    def __init__(self):
        self.points = []

    def select_point(self,event,x,y,flags,param):
            if event == cv2.EVENT_LBUTTONDBLCLK:
                cv2.circle(img,(x,y),3,(255,0,0),-1)
                self.points.append((x,y))


#instantiate class
coordinateStore1 = CoordinateStore()


# Create a black image, a window and bind the function to window
img = np.zeros((512,512,3), np.uint8)
cv2.namedWindow('image')
cv2.setMouseCallback('image',coordinateStore1.select_point)

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


print "Selected Coordinates: "
for i in coordinateStore1.points:
    print i