python OpenCV, draw grid example source code

make well divided linear coordinate
And make pair coordinate

Please see code for detail explanation.

import numpy as np

import cv2

import sys

rows = 500

cols = 500

newMat_3ch = np.zeros((rows, cols, 3), dtype = "uint8") #3channel

step = 20

x = np.linspace(start=0, stop=rows, num=step)

y = np.linspace(start=0, stop=cols, num=step)

v_xy = []

h_xy = []

for i in range(step):

v_xy.append( [int(x[i]), 0, int(x[i]), rows-1] )

h_xy.append( [0, int(y[i]), cols-1, int(y[i])] )

for i in range(step):

[x1, y1, x2, y2] = v_xy[i]

[x1_, y1_, x2_, y2_] = h_xy[i]

cv2.line(newMat_3ch, (x1,y1), (x2, y2), (0,0,255),1 )

cv2.line(newMat_3ch, (x1_,y1_), (x2_, y2_), (255,0,0),1 )

cv2.namedWindow('newMat_3ch',0)

cv2.imshow('newMat_3ch', newMat_3ch)

cv2.waitKey(0)