Simple interpolation technique for plotting missing points between two key points

Line interpolation

function lineInterpolate(point1, point2, distance) {
  var xabs = Math.abs( point1.x - point2.x );
  var yabs = Math.abs( point1.y - point2.y );
  var xdiff = point2.x - point1.x;
  var ydiff = point2.y - point1.y;

  var length = Math.sqrt( ( Math.pow( xabs, 2 ) + Math.pow( yabs, 2 ) ) );
  var steps = length / distance;
  var xstep = xdiff / steps;
  var ystep = ydiff / steps;

  var newx = 0;
  var newy = 0;
  var result = new Array();

  for( var s = 0; s < steps; s++ ) {
    newx = point1.x + ( xstep * s );
    newy = point1.y + ( ystep * s );
            
    result.push( {
      x: newx,
      y: newy
    } );
  }

  return result;
}