/// <summary>
/// Calculates the distance from the path.
/// </summary>
/// <param name="point">The point.</param>
/// <returns>Returns the distance from the path</returns>
public PointInfo DistanceFromPath(PointF point)
{
PointInfoInternal internalInfo = default;
internalInfo.DistanceSquared = float.MaxValue; // Set it to max so that CalculateShorterDistance can reduce it back down
int polyCorners = this.points.Length;
if (!this.closedPath)
{
polyCorners -= 1;
}
int closestPoint = 0;
for (int i = 0; i < polyCorners; i++)
{
int next = i + 1;
if (this.closedPath && next == polyCorners)
{
next = 0;
}
if (this.CalculateShorterDistance(this.points[i].Point, this.points[next].Point, point, ref internalInfo))
{
closestPoint = i;
}
}
return new PointInfo
{
DistanceAlongPath = this.points[closestPoint].TotalLength + Vector2.Distance(this.points[closestPoint].Point, internalInfo.PointOnLine),
DistanceFromPath = MathF.Sqrt(internalInfo.DistanceSquared),
SearchPoint = point,
ClosestPointOnPath = internalInfo.PointOnLine
};
}
/// <summary>
/// Calculates the distance from the path.
/// </summary>
/// <param name="point">The point.</param>
/// <returns>Returns the distance from the path</returns>
public PointInfo DistanceFromPath(PointF point)
{
if (IsDisposed)
{
throw new ObjectDisposedException(nameof(InternalPath));
}
PointInfoInternal internalInfo = default;
internalInfo.DistanceSquared = float.MaxValue; // Set it to max so that CalculateShorterDistance can reduce it back down
int polyCorners = _points.Count;
if (!closedPath)
{
polyCorners -= 1;
}
int closestPoint = 0;
for (int i = 0; i < polyCorners; i++)
{
int next = i + 1;
if (closedPath && next == polyCorners)
{
next = 0;
}
if (CalculateShorterDistance(_points[i].Point, _points[next].Point, point, ref internalInfo))
{
closestPoint = i;
}
}
return(new PointInfo
{
DistanceAlongPath = _points[closestPoint].TotalLength + Vector2.Distance(_points[closestPoint].Point, internalInfo.PointOnLine),
DistanceFromPath = (float)Math.Sqrt(internalInfo.DistanceSquared),
SearchPoint = point,
ClosestPointOnPath = internalInfo.PointOnLine
});
}
/// <summary>
/// Calculate any shorter distances along the path.
/// </summary>
/// <param name="start">The start position.</param>
/// <param name="end">The end position.</param>
/// <param name="point">The current point.</param>
/// <param name="info">The info.</param>
/// <returns>
/// The <see cref="bool"/>.
/// </returns>
private bool CalculateShorterDistance(Vector2 start, Vector2 end, Vector2 point, ref PointInfoInternal info)
{
Vector2 diffEnds = end - start;
float lengthSquared = diffEnds.LengthSquared();
Vector2 diff = point - start;
Vector2 multiplied = diff * diffEnds;
float u = (multiplied.X + multiplied.Y) / lengthSquared;
if (u > 1)
{
u = 1;
}
else if (u < 0)
{
u = 0;
}
Vector2 multipliedByU = diffEnds * u;
Vector2 pointOnLine = start + multipliedByU;
Vector2 d = pointOnLine - point;
float dist = d.LengthSquared();
if (info.DistanceSquared > dist)
{
info.DistanceSquared = dist;
info.PointOnLine = pointOnLine;
return(true);
}
return(false);
}
