Python OpenCV —— geometric

　　用OpenCV画几何图形。

import numpy as np
import cv2

# Create a black image
img = np.zeros((521,512,3), np.uint8)
# Draw a diagonal blue line with thickness of 5 px
# 背景数据，直线起点，直线终点，颜色，线条粗细
img = cv2.line(img,(0,0),(511,511),(255,0,0),5)
# print(img)

# Drawing Rectangle
# “背景（包含之前已经画到img的内容）”，矩形左上角，矩形右下角，颜色，线条粗细
img = cv2.rectangle(img,(384,0),(510,128),(0,255,0),3)

# Drawing Circle
#背景数据；圆心；半径；颜色；LineType[-1代表选择纯色填充]
img = cv2.circle(img,(447,63),63,(0,0,255),-1)

# Drawing Ellipse
# 背景；对称中心；长短轴长；整个椭圆旋转角度（顺时针）；
# 起始角度位置；终止角度位置（顺）；颜色；LineType
img = cv2.ellipse(img,(256,256),(100,50),0,0,180,255,-1)

# Drawing Polygon
pts = np.array([[10,5],[20,30],[70,20],[50,10]],np.int32)
pts = pts.reshape((-1,1,2))
# polylines(img, pts, isClosed, color[, thickness[, lineType[, shift]]]) -> img
img = cv2.polylines(img,[pts],True,(0,255,255))

# Adding text to image
font = cv2.FONT_HERSHEY_SIMPLEX
cv2.putText(img,‘OpenCV‘,(10,500),font,4,(255,255,255),2,cv2.LINE_AA)

cv2.imshow(‘images‘,img)
cv2.waitKey(0)
cv2.destroyAllWindows()

　　输出：