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Line segment drawing

When processing images with OpenCV, we sometimes need to draw line segments, rectangles, etc. on the image.

In OpenCV, we use 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 parameter. The coordinate points of the line segment, representing the starting point and the 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 line segment, optional 8 (8 adjacent connecting lines - default), 4 (4 adjacent connecting lines) and cv2.LINE_AA for anti-aliasing

Code path:

x
~/dofbot_ws/src/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 a 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()