python opencv实现简易画图板

python-opencv实现简易画图板，供大家参考，具体内容如下

# -*- 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:
#        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()

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。