python_openCV学习笔记(1) 绘制openCV的logo

1.创建背景为白色的画布：

img=np.ones((512,512,3),np.uint8)*255

2.绘制三个圆环：

cv2.circle(img,(256,100),60,(0,0,255),-1)
cv2.circle(img,(256,100),25,(255,255,255),-1)

cv2.circle(img,(181,228),60,(0,255,0),-1)
cv2.circle(img,(181,228),25,(255,255,555),-1)

cv2.circle(img,(331,228),60,(255,0,0),-1)
cv2.circle(img,(331,228),25,(255,255,255),-1)

结果图：


3.在圆环上叠加三角形，形成缺口圆环的效果：
tri1=np.array([256,100,219,164,293,164],np.int32)
tri1=tri1.reshape((-1,1,2))

tri2=np.array([[181,228],[256,228],[218,164]],np.int32)

tri3=np.array([[331,228],[368,164],[293,164]],np.int32)

cv2.fillPoly(img,[tri1,tri2,tri3],(0,255,255));
关于fillPoly和fillConvexPoly两个函数的区别，参考这里。

为了方便看清，颜色先调成了黄色。

结果图：



4.添加文字：

font=cv2.FONT_HERSHEY_SIMPLEX
cv2.putText(img,'OpenCV',(121,350),font,2.3,(0,0,0),10)

最终结果图：



完整代码：

import numpy as np
import cv2

img=np.ones((512,512,3),np.uint8)*255

cv2.circle(img,(256,100),60,(0,0,255),-1)
cv2.circle(img,(256,100),25,(255,255,255),-1)

cv2.circle(img,(181,228),60,(0,255,0),-1)
cv2.circle(img,(181,228),25,(255,255,555),-1)

cv2.circle(img,(331,228),60,(255,0,0),-1)
cv2.circle(img,(331,228),25,(255,255,255),-1)

tri1=np.array([256,100,219,164,293,164],np.int32)
tri1=tri1.reshape((-1,1,2))

tri2=np.array([[181,228],[256,228],[218,164]],np.int32)

tri3=np.array([[331,228],[368,164],[293,164]],np.int32)

cv2.fillPoly(img,[tri1,tri2,tri3],(255,255,255));

font=cv2.FONT_HERSHEY_SIMPLEX
cv2.putText(img,'OpenCV',(121,350),font,2.3,(0,0,0),10)

cv2.imshow('openCV',img)
cv2.waitKey(0)
cv2.destroyWindow('openCV')
cv2.waitKey(1)