title: How to find a point along a contour path given the distance from a point on the contour?
body: <p>I have a contour with certain points defined.
  I m trying to offset the position of the starting point by a certain distance along the contour like shown below.
  Pt A to Pt A'. I have the offset distance as say 0.5 mm.
  I already have details of co-ordinates of Pt A.</p>
  <ul>
  <li>How to find the coordinates of A'(along the contour path), given the offset value ( <em><strong>This offset is not the linear distance but the distance along the contour</strong></em>)?</li>
  <li>Additionally how to programmatically achieve this in C++ or JAVA?</li>
  </ul>
  <p><a href="https://i.stack.imgur.com/zkYn4.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/zkYn4.jpg" alt="Contour Path" /></a></p>