python opencv实现简易画图板

 # -*- coding: utf-8 -*- """ Created on Sat May 19 17:34:54 2018 @author: xxx """ import cv2 as cv import numpy as np def nothing(x): pass # 当鼠标按下时变为 True drawing = False # 如果 mode 为 True 绘制矩形。按下 'm' 变成绘制曲线 mode = True ix, iy = -1, -1 #创建回调函数 def draw_circle(event, x, y, flags, param): r = cv.getTrackbarPos('R', 'image') g = cv.getTrackbarPos('G', 'image') b = cv.getTrackbarPos('B', 'image') color = (b, g, r) global ix, iy, drawing, mode # 当按下左键是返回起始位置坐标 if event == cv.EVENT_LBUTTONDOWN: drawing = True ix, iy = x, y #    当鼠标左键按下并移动是绘制图形。event 可以查看移动, flag 查看是否按下 elif event == cv.EVENT_MOUSEMOVE and flags == cv.EVENT_FLAG_LBUTTON: if drawing == True: if mode == True: cv.rectangle(img, (ix, iy), (x, y), color, -1) else: # 绘制圆圈，小圆点连在一起就成了线，3代表画笔的粗细 cv.circle(img, (ix, iy), 3, color, -1) # 下面注释的代码是起始点为圆心，起点到终点为半径 #        r = int(np.sqrt((x - ix)**2 + (y - iy)**2)) #        cv.circle(img, (x, y), r, (0, 0, 255), -1) #    当鼠标松开停止绘画 elif event == cv.EVENT_LBUTTONUP: drawing == False #      if mode == True: #   <a style="color:transparent">来源gao($daima.com搞@代@#码(网</a>     cv.rectangle(img, (ix, iy), (x, y), (0, 255, 0), -1) #      else: #      cv.circle(img, (x, y), 5, (0, 0, 255), -1) #创建一幅黑色图形 img = np.zeros((512, 512, 3), np.uint8) cv.namedWindow('image') cv.createTrackbar('R', 'image', 0, 255, nothing) cv.createTrackbar('G', 'image', 0, 255, nothing) cv.createTrackbar('B', 'image', 0, 255, nothing) cv.setMouseCallback('image', draw_circle) while(1): cv.imshow('image', img) k = cv.waitKey(1)&0xFF if k == ord('m'): mode = not mode elif k==27: break cv.destroyAllWindow()