/// <override></override>
public override RelativePosition CalculateRelativePosition(int x, int y)
{
// The RelativePosition of a PolyLine is defined as
// A = ControlPointId of the first vertex of the nearest line segment (FirstVertex -> LastVertex)
// B = Angle between the line segment (A / next vertex of A) and the point
// C = Distance of the point from A in percentage of the line segment's length
RelativePosition result = RelativePosition.Empty;
Point p = Point.Empty;
p.Offset(x, y);
// Find the nearest line segment
int pointIdx = -1;
float angleFromA = float.NaN;
float distanceFromA = float.NaN;
float lowestAbsDistance = float.MaxValue;
float lineWidth = LineStyle.LineWidth / 2f + 2;
int cnt = vertices.Count - 1;
for (int i = 0; i < cnt; ++i)
{
float dist = Geometry.DistancePointLine(p, vertices[i], vertices[i + 1], true);
if (dist < lowestAbsDistance)
{
lowestAbsDistance = dist;
pointIdx = i;
if (dist > lineWidth)
{
angleFromA = ((360 + Geometry.RadiansToDegrees(Geometry.Angle(vertices[i], vertices[i + 1], p))) % 360);
}
else
{
angleFromA = 0;
}
distanceFromA = Geometry.DistancePointPoint(vertices[i], p);
}
}
if (pointIdx >= 0)
{
result.A = GetControlPointId(pointIdx);
result.B = Geometry.DegreesToTenthsOfDegree(angleFromA);
float segmentLength = Geometry.DistancePointPoint(vertices[pointIdx], vertices[pointIdx + 1]);
if (segmentLength == 0)
{
result.C = 0;
}
else
{
result.C = (int)Math.Round((distanceFromA / (segmentLength / 100)) * 10);
}
Debug.Assert(result.B >= 0 && result.B <= 3600, "Calculated angle is out of range.");
}
if (result == RelativePosition.Empty)
{
result.A = result.B = result.C = 0;
}
return(result);
}
/// <override></override>
public override Point CalculateAbsolutePosition(RelativePosition relativePosition)
{
// The RelativePosition of a PolyLine is defined as
// A = ControlPointId of the first vertex of the nearest line segment (FirstVertex -> LastVertex)
// B = Angle between the line segment (A / next vertex of A) and the point
// C = Distance of the point from A in percentage of the line segment's length
Point result = Point.Empty;
int idx = GetControlPointIndex(relativePosition.A);
float angle = Geometry.TenthsOfDegreeToDegrees(relativePosition.B);
float distance = relativePosition.C / 1000f;
if (distance != 0)
{
float segmentLength = Geometry.DistancePointPoint(vertices[idx], vertices[idx + 1]);
Point p = Geometry.VectorLinearInterpolation(vertices[idx], vertices[idx + 1], (distance));
result = Geometry.RotatePoint(vertices[idx], angle, p);
Debug.Assert(Geometry.IsValid(result));
}
else
{
result = vertices[idx];
}
return(result);
}
/// <summary> /// Calculates the absolute position of a RelativePosition. /// </summary> public abstract Point CalculateAbsolutePosition(RelativePosition relativePosition);