python - python画图不连续怎么解决

Question

这是我的代码:

import numpy as np
import cv2
drawing = False

def draw_circle(event,x,y,flags,param):
  global ix,iy,drawing

  if event == cv2.EVENT_LBUTTONDOWN:
    drawing= True
    ix,iy=x,y
  elif event == cv2.EVENT_MOUSEMOVE and flags == cv2.EVENT_FLAG_LBUTTON:
    if drawing == True:
      cv2.circle(img,(x,y),3,(0,0,0),-1)
  elif event == cv2.EVENT_LBUTTONUP:
    drawing == False

img=np.ones((512,512,3),np.uint8)*255
cv2.namedWindow('image')
cv2.setMouseCallback('image',draw_circle)

while(True):
  cv2.imshow('image',img)

  if cv2.waitKey(1)&0xff == ord('q'):
    break

cv2.destroyAllWindows()

第一条线画得慢，第二条线画得快:

我的问题是:

1. 是什么导致了这个问题？
2. 如何解决。

Answer 1

不要使用circle，当你使用circle时，在快速移动时会有间隙。会有间隙，因为当您快速移动时，在绘制前一个圆圈之前会引发新的鼠标事件。使用 line 代替如下:

def draw_circle(event,x,y,flags,param):
 global ix,iy,drawing

 if event == cv2.EVENT_LBUTTONDOWN:
   drawing= True
   ix,iy=x,y
 elif event == cv2.EVENT_MOUSEMOVE and flags == cv2.EVENT_FLAG_LBUTTON:
   if drawing:
     cv2.line(img,(ix,iy),(x,y),(0,0,0), 3)
     ix,iy = x,y
 elif event == cv2.EVENT_LBUTTONUP:
   drawing == False