camshift.py 文件源码

def mouse_event(self, event, x, y, flags, param):
        # Convert x and y coordinates into 16-bit numpy integers
        x, y = np.int16([x, y]) 

        # Check if a mouse button down event has occurred
        if event == cv2.EVENT_LBUTTONDOWN:
            self.drag_start = (x, y)
            self.tracking_state = 0

        # Check if the user has started selecting the region
        if self.drag_start:
            if flags & cv2.EVENT_FLAG_LBUTTON:
                # Extract the dimensions of the frame
                h, w = self.frame.shape[:2]

                # Get the initial position
                xi, yi = self.drag_start

                # Get the max and min values
                x0, y0 = np.maximum(0, np.minimum([xi, yi], [x, y]))
                x1, y1 = np.minimum([w, h], np.maximum([xi, yi], [x, y]))

                # Reset the selection variable
                self.selection = None

                # Finalize the rectangular selection
                if x1-x0 > 0 and y1-y0 > 0:
                    self.selection = (x0, y0, x1, y1)

            else:
                # If the selection is done, start tracking  
                self.drag_start = None
                if self.selection is not None:
                    self.tracking_state = 1

    # Method to start tracking the object