cv2-drawline

---

title: cv2 drawline
date: 2022-07-02 21:23:50
tags: opencv

cv2 drawline

import numpy as np
import cv2 as cv

def draw_line():
    ''' 画直线 cv.line(img, pt1, pt2, color, thickness) Parameters: img Image. pt1 First point of the line segment. pt2 Second point of the line segment. color Line color. thickness Line thickness. lineType Type of the line. See LineTypes. shift Number of fractional bits in the point coordinates. '''
    #创建一个黑色的图像
    img = np.zeros((512, 512, 3), np.uint8)

    #画一条5px宽的对角线
    cv.line(img, (0, 0), (511, 511), (255, 0, 0), 5)

    #显示图片
    cv.imshow('img', img)

    key = cv.waitKey(0)
    if key == ord('q'):
        cv.destroyAllWindows()


def draw_rectangle():

    ''' 画矩形 cv.rectangle(img, pt1, pt2, color, thickness) Parameters img Image. pt1 Vertex of the rectangle. pt2 Vertex of the rectangle opposite to pt1 . color Rectangle color or brightness (grayscale image). thickness Thickness of lines that make up the rectangle. Negative values, like FILLED, mean that the function has to draw a filled rectangle. lineType Type of the line. See LineTypes shift Number of fractional bits in the point coordinates. '''

    img = np.zeros((512, 512, 3), np.uint8)
    cv.rectangle(img, (384, 0), (510, 128), (0, 256, 0), 3)
    
    cv.imshow('img', img)
    key = cv.waitKey(0)
    if key == ord('q'):
        cv.destroyAllWindows()

def draw_circle():
    ''' '''
    img = np.zeros((512, 512), np.uint8)
    cv.circle(img,(447,63), 63, (0,0,255), -1)
    # cv.circle(img, (200, 63), 63, (0, 255, 0), 3)
    cv.imshow('img', img)
    key = cv.waitKey(0)
    if key == ord('q'):
        cv.destroyAllWindows()

def draw_polylines():
    img = np.zeros((512, 512, 3), np.uint8)
    pts = np.array([[10,5],[20,30],[70,20],[50,10]], np.int32)
    pts = pts.reshape((-1, 1, 2))
    cv.polylines(img, [pts], True, (0, 255, 255))

    cv.imshow('img', img)
    key = cv.waitKey(0)
    if key == ord('q'):
        cv.destroyAllWindows()
    print(pts.shape)