/// <summary>
/// Gets the nearest line segment index from the given point.
/// </summary>
/// <returns>The smaller index of the segment vertex, or -1 if the point is too far from the segments.</returns>
protected static int GetSegmentIndex(IList <Point> vertices, Point point, double maxDistance = 5)
{
if (vertices.Count < 2)
{
return(-1);
}
var nearestIndex = -1;
var nearestDist = double.PositiveInfinity;
for (int i = 0, j = vertices.Count - 1; i < j; i++)
{
if (!CanvasHelper.IsBetweenPoints(point, vertices[i], vertices[i + 1]))
{
continue;
}
var dist = CanvasHelper.DistanceToLine(point, vertices[i], vertices[i + 1]);
if (dist > maxDistance)
{
continue;
}
if (dist < nearestDist)
{
nearestIndex = i;
nearestDist = dist;
}
}
return(nearestIndex);
}