When drawing an arbitrary point in an image, how to find the coordinates of the two closest lines perpendicular to that point?

Question

I draw an arbitrary point in this image.

I want to find the coordinates of the two lines closest to this point.

It should be a straight line when you connect one of the two points to any point.

Like this:

I want to know two thing

• First, Is there a library to find the nearest line from an arbitrary point?

• Second, Is there any library or algorithm to find a point perpendicular to an arbitrary point?

Please help me.....

Answer 1

You can do this in two steps: first for the closest line, then for the other one.

• The closest line : Let A be the arbitrary point. You can calculate the distance of each white pixel to point A and keep the shortest distance (sqrt((xa.x)^2 + (ya.y)^2) . This closest pixel (let's call it P ) is the projected point on the line. By definition of the projected point, the line AP is perpendicular to the line.
• The other line : color all the points of the closest line so as not to search again in its pixels, do the same thing as for the closest line.