在类里使用python opencv实现鼠标区域截图

可以使用以下代码实现：

import cv2

class MouseScreenShot():
    def __init__(self):
        self.start_x = None
        self.start_y = None
        self.end_x = None
        self.end_y = None
        self.drawing = False

    def capture(self):
        cv2.namedWindow('image')
        cv2.setMouseCallback('image', self.draw_rect)

        while True:
            image = cv2.imread("test.png")  # 此处为截取电脑屏幕可替换为其他图像路径
            cv2.imshow('image', image)

            if cv2.waitKey(1) == ord('c'):
                if self.start_x is not None and self.start_y is not None and self.end_x is not None and self.end_y is not None:
                    x1 = min(self.start_x, self.end_x)
                    y1 = min(self.start_y, self.end_y)
                    x2 = max(self.start_x, self.end_x)
                    y2 = max(self.start_y, self.end_y)
                    roi = image[y1:y2, x1:x2]
                    cv2.imwrite('capture.png', roi)
                    break

        cv2.destroyAllWindows()

    def draw_rect(self, event, x, y, flags, param):
        if event == cv2.EVENT_LBUTTONDOWN:
            self.drawing = True
            self.start_x, self.start_y = x, y
            self.end_x, self.end_y = x, y
        elif event == cv2.EVENT_MOUSEMOVE:
            if self.drawing:
                self.end_x, self.end_y = x, y
        elif event == cv2.EVENT_LBUTTONUP:
            self.drawing = False

在代码中，通过使用cv2.namedWindow() 和cv2.setMouseCallback()函数，程序将窗口('image')进行注册，并将鼠标的事件与函数self.draw_rect()进行绑定，从而实现在鼠标移动时的图像显示。通过cv2.waitKey(1)监听用户的行为，当用户按下 'c' 键时，将鼠标所选区域的像素点截取并保存，最后退出程序。