Let's see how we can use the mouse to interact with a live video stream from the webcam. We can use the mouse to select a region, and then apply a negative film effect on that region, as shown in the following image:
In the following program, we will capture the video stream from the webcam, select a region of interest with the mouse, and then apply this effect:
import cv2
import numpy as np
def update_pts(params, x, y):
global x_init, y_init
params["top_left_pt"] = (min(x_init, x), min(y_init, y))
params["bottom_right_pt"] = (max(x_init, x), max(y_init, y))
img[y_init:y, x_init:x] = 255 - img[y_init:y, x_init:x]
def draw_rectangle(event, x, y, flags, params):
global x_init, y_init, drawing
# First click initialize the init rectangle point
if event == cv2.EVENT_LBUTTONDOWN:
drawing = True
x_init, y_init = x, y
# Meanwhile mouse button is pressed, update diagonal rectangle point
elif event ==...