OpenCV

鼠标事件

1. 创建窗口
2. 设置窗口大小
3. 鼠标事件监听
   • 判断事件更新起始点和终点
   • 绘制线
   • 显示图片
4. 打开背景图

"""
鼠标事件
down
up
move
"""
import cv2
import numpy as npWINNAME = 'DRAWBOARD'
st_point = (-1, -1)
end_point = (-1, -1)def drawLine(event, x, y, flags, param):global st_point, end_pointimg_copy = bg_img.copy()if event == cv2.EVENT_LBUTTONDOWN:print('EVENT_LBUTTONDOWN', event, x, y, flags, param)st_point = (x, y)if event == cv2.EVENT_MOUSEMOVE and flags:end_point = (x, y)cv2.line(img_copy, st_point, end_point, color=(0, 0, 255), thickness=2)cv2.imshow(WINNAME, img_copy)if event == cv2.EVENT_LBUTTONUP:print('EVENT_LBUTTONUP', event, x, y, flags, param)end_point = (x, y)# 绘制线# 起始点 终点cv2.line(bg_img, st_point, end_point, color=(0, 0, 255), thickness=2)cv2.imshow(WINNAME, bg_img)def drawRectangle(event, x, y, flags, param):global st_point, end_pointimg_copy = bg_img.copy()if event == cv2.EVENT_LBUTTONDOWN:print('EVENT_LBUTTONDOWN', event, x, y, flags, param)st_point = (x, y)if event == cv2.EVENT_MOUSEMOVE and flags:end_point = (x, y)cv2.rectangle(img_copy, st_point, end_point, color=(0, 0, 255), thickness=2)cv2.imshow(WINNAME, img_copy)if event == cv2.EVENT_LBUTTONUP:print('EVENT_LBUTTONUP', event, x, y, flags, param)end_point = (x, y)# 绘制线# 起始点 终点cv2.rectangle(bg_img, st_point, end_point, color=(0, 0, 255), thickness=2)cv2.imshow(WINNAME, bg_img)def drawPolylines(event, x, y, flags, param):global st_point, end_pointif event == cv2.EVENT_LBUTTONDOWN:print('EVENT_LBUTTONDOWN', event, x, y, flags, param)st_point = (x, y)end_point = st_pointif event == cv2.EVENT_MOUSEMOVE and flags:last_x, last_y = st_point, end_pointst_point = end_pointend_point = (x, y)print('EVENT_MOUSEMOVE', event, x, y, flags, param)pts = np.array([last_x, last_y, st_point, end_point])cv2.polylines(bg_img, [pts], isClosed=False, color=(0, 0, 255), thickness=2)cv2.imshow(WINNAME, bg_img)if event == cv2.EVENT_LBUTTONUP:print('EVENT_LBUTTONUP', event, x, y, flags, param)last_x, last_y = st_point, end_pointst_point = end_pointend_point = (x, y)# 绘制线# 起始点 终点pts = np.array([last_x, last_y, st_point, end_point])cv2.polylines(bg_img, [pts], isClosed=False, color=(0, 0, 255), thickness=2)cv2.imshow(WINNAME, bg_img)def callBack(event, x, y, flags, param):# drawLine(event, x, y, flags, param)# drawRectangle(event, x, y, flags, param)drawPolylines(event, x, y, flags, param)if __name__ == '__main__':# 创建窗口cv2.namedWindow(WINNAME, cv2.WINDOW_NORMAL)# 设置窗口大小cv2.resizeWindow(WINNAME, 360, 360)# 鼠标事件的监听# 参数1 事件监听的窗口名称# 参数2 函数名称 用于回调使用cv2.setMouseCallback(WINNAME, callBack, param='hello')# 打开背景图bg_img = cv2.imread('snower.jpg')cv2.imshow(WINNAME, bg_img)cv2.waitKey(0)cv2.destroyAllWindows()

鼠标绘制直线

鼠标绘制矩形

鼠标绘制曲线