mathgeometrytrigonometrycartesian

Calculate offset coordinate in a cartesian space

if I have 2 coordinate pointA(x,y) and pointB(x,y)

I need to calculate the offset coordinate at specific distance and angle 90 deg and 270 deg. How can I?

Can't find the right formula.

How to get the coordinate of C,D,E,F?

pic

Solution

  • Difference vector

    dx = B.X - A.X
dy = B.Y - A.Y

    Perpendicular vector

    px = -dy
py = dx

    Vector length (perhaps you have ready function Hypot or alike function in your math library)

    len = sqrt(px*px+py*py)

    Normalized (unit length) vector

    nx = px / len
ny = py / len

    Now find points at distance dist:

    C.X = A.X + nx * dist
C.Y = A.Y + nY * dist

G.X = A.X - nx * dist
G.Y = A.Y - nY * dist

    similar for points around B