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Line Segment Drawing

When using OpenCV to process images, we sometimes need to draw line segments, rectangles, etc. on the image. OpenCV uses the line(dst, pt1, pt2, color, thickness=None, lineType=None, shift=None) function to draw line segments.

Parameter description:

dst: Output image.

pt1, pt2: Required parameters. Coordinate points of the line segment, representing the start point and end point respectively.

color: Required parameter. Used to set the color of the line segment.

thickness: Optional parameter. Used to set the width of the line segment.

lineType: Optional parameter. Used to set the type of the line segment. Options are 8 (8-connected line - default), 4 (4-connected line), and cv2.LINE_AA for anti-aliasing.

Code path:

~/dofbot_opencv/scripts/3.draw_picture/04_draw_line.ipynb

​x
import cv2
import numpy as np
import matplotlib.pyplot as plt
newImageInfo = (600, 600, 3)
dst = np.zeros(newImageInfo,np.uint8)
​
# line
# draw line segment 1 dst 2 begin 3 end 4 color
cv2.line(dst, (100,100), (450,300), (0,0,255))
# 5 line w
cv2.line(dst, (100,200), (400,200), (0,255,255), 10)
# 6 line type
cv2.line(dst, (100,300), (400,300), (0,255,0), 10, cv2.LINE_AA)
​
cv2.line(dst, (200,150), (50,250), (25,100,255))
cv2.line(dst, (50,250), (400,380), (25,100,255))
cv2.line(dst, (400,380), (200,150), (25,100,255))
​
# cv2.imshow('dst',dst)
# cv2.waitKey(0)
dst = cv2.cvtColor(dst, cv2.COLOR_BGR2RGB)
plt.imshow(dst)
    plt.show()