Python基于opencv实现的简单画板功能示例

本文实例讲述了python基于opencv实现的简单画板功能。分享给大家供大家参考，具体如下：

import cv2
import numpy as np
drawing = false # true if mouse is pressed
ix,iy = -1,-1
def nothing(x):
  pass
# mouse callback function
def draw_circle(event,x,y,flags,param):
  global ix,iy,drawing
  g = param[0]
  b = param[1]
  r = param[2]
  shape = param[3]
  if event == cv2.event_lbuttondown:
    drawing = true
    ix,iy = x,y
  elif event == cv2.event_mousemove:
    if drawing == true:
      if shape == 0:
        cv2.rectangle(img,(ix,iy),(x,y),(g,b,r),-1)
      else:
        cv2.circle(img,(x,y),5,(g,b,r),-1)
  elif event == cv2.event_lbuttonup:
    drawing = false
    if shape == 0:
      cv2.rectangle(img,(ix,iy),(x,y),(g,b,r),-1)
    else:
      cv2.circle(img,(x,y),5,(g,b,r),-1)
# create a black image, a window
img = np.zeros((300,512,3), np.uint8)
cv2.namedwindow('image')
# create trackbars for color change
cv2.createtrackbar('r','image',0,255,nothing)
cv2.createtrackbar('g','image',0,255,nothing)
cv2.createtrackbar('b','image',0,255,nothing)
# create switch for on/off functionality
switch1 = '0 : off \n1 : on'
switch2 = '0: rectangle \n1: line '
cv2.createtrackbar(switch1, 'image',0,1,nothing)
cv2.createtrackbar(switch2, 'image',0,1,nothing)
while(1):
  cv2.imshow('image',img)
  k = cv2.waitkey(1) & 0xff
  # get current positions of four trackbars
  if k == 27:
      break
  r = cv2.gettrackbarpos('r','image')
  g = cv2.gettrackbarpos('g','image')
  b = cv2.gettrackbarpos('b','image')
  shape = cv2.gettrackbarpos(switch2,'image')
  s = cv2.gettrackbarpos(switch1,'image')
  if s == 0:
    img[:] = 0
  else:
    if k == 27:
      break
    cv2.setmousecallback('image',draw_circle,(b,g,r,shape))
cv2.destroyallwindows()

运行效果：

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希望本文所述对大家python程序设计有所帮助。