//=====================================================================
// IsPointInLine(double x, double y, XYLine line) : bool
//=====================================================================
/// <summary>
/// Determines if a point is included in a line either in the interior
/// or as one of the end points.
/// </summary>
/// <param name="x">x-coordinate</param>
/// <param name="y">y-coordinate</param>
/// <param name="line">Line.</param>
/// <returns>
/// <p>Determines if a point is included in a line.</p>
/// </returns>
protected static bool IsPointInLine(double x, double y, XYLine line)
{
bool result = false;
if (line.P1.X - line.P2.X != 0)
{
if ((x >= Math.Min(line.P1.X, line.P2.X)) && (x <= Math.Max(line.P1.X, line.P2.X)))
{
if (Math.Abs(y - line.P1.Y - (line.P2.Y - line.P1.Y) / (line.P1.X - line.P2.X) * (line.P1.X - x)) < EPSILON * EPSILON)
{
result = true;
}
}
}
else
{
if (line.P1.X == x)
{
if ((y >= Math.Min(line.P1.Y, line.P2.Y)) && (y <= Math.Max(line.P1.Y, line.P2.Y)))
{
result = true;
}
}
}
return(result);
}
//=====================================================================
// CalculateLineToPointDistance (XYLine line, XYPoint point) : double
//=====================================================================
/// <summary>
/// Calculates the distance from a polyline to a point in the plane.
/// The algorithm decides weather the point lies besides the line
/// segment in which case the distance is the length along a line
/// perpendicular to the line. Alternatively the distance is the
/// smallest of the distances to either endpoint.
/// </summary>
/// <param name="line">Line</param>
/// <param name="point">Point</param>
/// <returns>
/// <p>Length of the shortest path between the line and the point.</p>
/// </returns>
protected static double CalculateLineToPointDistance(XYLine line, XYPoint point)
{
double dist;
double a = Math.Sqrt((line.P2.X - point.X) * (line.P2.X - point.X) + (line.P2.Y - point.Y) * (line.P2.Y - point.Y));
double b =
Math.Sqrt((line.P2.X - line.P1.X) * (line.P2.X - line.P1.X) + (line.P2.Y - line.P1.Y) * (line.P2.Y - line.P1.Y));
double c = Math.Sqrt((line.P1.X - point.X) * (line.P1.X - point.X) + (line.P1.Y - point.Y) * (line.P1.Y - point.Y));
if ((a == 0) || (c == 0))
{
dist = 0;
}
else if (b == 0)
{
dist = a;
}
else
{
double alpha = Math.Acos((b * b + c * c - a * a) / (2 * b * c));
double beta = Math.Acos((a * a + b * b - c * c) / (2 * a * b));
if (Math.Max(alpha, beta) < Math.PI / 2)
{
dist = Math.Abs((line.P2.X - line.P1.X) * (line.P1.Y - point.Y) - (line.P1.X - point.X) * (line.P2.Y - line.P1.Y)) / b;
}
else
{
dist = Math.Min(a, c);
}
}
return(dist);
}
//=====================================================================
// IsPointInLineInterior(double x, double y, XYLine line) : bool
//=====================================================================
/// <summary>
/// Determines if a point is included in a lines interior. I.e. included
/// in the line and not an endpoint.
/// </summary>
/// <param name="x">x-coordinate</param>
/// <param name="y">y-coordinate</param>
/// <param name="line">Line.</param>
/// <returns>
/// <p>Determines if a point is included in a line.</p>
/// </returns>
protected static bool IsPointInLineInterior(double x, double y, XYLine line)
{
bool result = false;
if (line.P1.X - line.P2.X != 0) //line is not vertical
{
if ((x > Math.Min(line.P1.X, line.P2.X)) && (x < Math.Max(line.P1.X, line.P2.X)))
{
if (Math.Abs(y - line.P1.Y - (line.P2.Y - line.P1.Y) / (line.P1.X - line.P2.X) * (line.P1.X - x)) < EPSILON * EPSILON)
{
result = true;
}
}
}
else //line is vertical
{
if (line.P1.X == x)
{
if ((y > Math.Min(line.P1.Y, line.P2.Y)) && (y < Math.Max(line.P1.Y, line.P2.Y)))
{
result = true;
}
}
}
return(result);
}
//=====================================================================
// IntersectionPoint(XYLine lineA, XYLine lineB, ref intersectionPoint): bool
//=====================================================================
/// <summary>
/// Checks if the lines lineA and lineB shares a point either as a real
/// crossing point or as a shared end point or a end point of the one
/// line being in the other line.
/// </summary>
/// <param name="Linea">Line.</param>
/// <param name="Lineb">Line.</param>
/// <param name="intersectionPoint">Point.</param>
/// <returns>
/// <p>True if lineA and lineB has shared point. False otherwise</p>
/// <p>The shared point if any is returned in the intersectionPoint
/// parameter that is called by reference</p>
/// </returns>
protected static bool IntersectionPoint(XYLine Linea, XYLine Lineb, ref XYPoint intersectionPoint)
{
if (DoLineSegmentsIntersect(Linea, Lineb))
{
intersectionPoint = CalculateIntersectionPoint(Linea, Lineb);
return(true);
}
if (IsPointInLine(Linea.P2, Lineb))
{
intersectionPoint = Linea.P2;
return(true);
}
if (IsPointInLine(Lineb.P2, Linea))
{
intersectionPoint = Lineb.P2;
return(true);
}
if (IsPointInLine(Lineb.P1, Linea))
{
intersectionPoint = Lineb.P1;
return(true);
}
if (IsPointInLine(Linea.P1, Lineb))
{
intersectionPoint = Linea.P1;
return(true);
}
return(false);
}
//=====================================================================
// XYLine(XYLine line)
//=====================================================================
/// <summary>
/// Constructor. Copies input line.
/// </summary>
/// <param name="line">Line to copy</param>
public XYLine(XYLine line)
{
_p1 = new XYPoint();
_p2 = new XYPoint();
_p1.X = line.P1.X;
_p1.Y = line.P1.Y;
_p2.X = line.P2.X;
_p2.Y = line.P2.Y;
}
//=========================================================================================
//CalculateLengthOfPolylineInsidePolygon(XYPolyline polyline, XYPolygon polygon) : double
//=========================================================================================
/// <summary>
/// Calculates the length of polyline inside polygon. Lines segments on the edges of
/// polygons are included with half their length.
/// </summary>
/// <param name="polyline">Polyline</param>
/// <param name="polygon">Polygon</param>
/// <returns>
/// Length of polyline inside polygon.
/// </returns>
public static double CalculateLengthOfPolylineInsidePolygon(XYPolyline polyline, XYPolygon polygon)
{
double lengthInside = 0;
int numberOfLineSegments = polyline.Points.Count - 1;
for (int i = 0; i < numberOfLineSegments; i++)
{
XYLine line = new XYLine(polyline.GetLine(i));
lengthInside += CalculateLengthOfLineInsidePolygon(line, polygon);
}
return(lengthInside);
}
//=====================================================================
// IsPointInLineInterior(XYPoint point, XYLine line) : bool
//=====================================================================
/// <summary>
/// Determines if a point is included in a lines interior. I.e. included
/// in the line and not an endpoint.
/// <p>Overload to:IsPointInLineInterior(double x, double y, XYLine line)</p>
/// </summary>
/// <param name="point">Point.</param>
/// <param name="line">Line.</param>
/// <returns>
/// <p>Determines if a point is included in a line.</p>
/// </returns>
protected static bool IsPointInLineInterior(XYPoint point, XYLine line)
{
return(IsPointInLineInterior(point.X, point.Y, line));
}
//=====================================================================================
//CalculateLengthOfLineInsidePolygon(XYLine line, XYPolygon polygon): double
//=====================================================================================
/// <summary>
/// Calculates length of line inside polygon. Parts of the line that is on the edge of
/// the polygon only counts with half their length.
/// </summary>
/// <param name="line">Line</param>
/// <param name="polygon">Polygon</param>
/// <returns>
/// Length of line inside polygon.
/// </returns>
protected static double CalculateLengthOfLineInsidePolygon(XYLine line, XYPolygon polygon)
{
ArrayList lineList = new ArrayList();
lineList.Add(new XYLine(line));
for (int i = 0; i < polygon.Points.Count; i++) // For all lines in the polygon
{
for (int n = 0; n < lineList.Count; n++)
{
if (lineList.Count > 1000)
{
throw new Exception("Problems in ElementMapper, line has been cut in more than 1000 pieces !!!");
}
if (DoLineSegmentsIntersect((XYLine)lineList[n], polygon.GetLine(i)))
{
// Split the intersecting line into two lines
XYPoint IntersectionPoint = new XYPoint(CalculateIntersectionPoint((XYLine)lineList[n], polygon.GetLine(i)));
lineList.Add(new XYLine(IntersectionPoint, ((XYLine)lineList[n]).P2));
((XYLine)lineList[n]).P2.X = IntersectionPoint.X;
((XYLine)lineList[n]).P2.Y = IntersectionPoint.Y;
break;
}
}
}
for (int i = 0; i < lineList.Count; i++)
{
if (lineList.Count > 1000)
{
throw new Exception("Problems in ElementMapper, line has been cuttes in more than 100 pieces !!!");
}
for (int j = 0; j < polygon.Points.Count; j++)
{
if (IsPointInLineInterior(polygon.GetLine(j).P1, ((XYLine)lineList[i])))
{
lineList.Add(new XYLine(polygon.GetLine(j).P1, ((XYLine)lineList[i]).P2));
((XYLine)lineList[i]).P2.X = polygon.GetLine(j).P1.X;
((XYLine)lineList[i]).P2.Y = polygon.GetLine(j).P1.Y;
}
}
}
double lengthInside = 0;
for (int i = 0; i < lineList.Count; i++)
{
double sharedLength = 0;
for (int j = 0; j < polygon.Points.Count; j++)
{
sharedLength += CalculateSharedLength(((XYLine)lineList[i]), polygon.GetLine(j));
}
if (sharedLength > EPSILON)
{
lengthInside += sharedLength / 2;
}
else if (IsPointInPolygon(((XYLine)lineList[i]).GetMidpoint(), polygon))
{
lengthInside += ((XYLine)lineList[i]).GetLength();
}
}
return(lengthInside);
}
//=========================================================================================
//CalculateSharedLength(XYLine lineA, XYLine lineB) : double
//=========================================================================================
/// <summary>
/// Calculates the length that two lines overlap.
/// </summary>
/// <param name="lineA">Line</param>
/// <param name="lineB">Line</param>
/// <returns>
/// Length of shared line segment.
/// </returns>
protected static double CalculateSharedLength(XYLine lineA, XYLine lineB)
{
if (Math.Abs(lineA.P2.X - lineA.P1.X) < EPSILON && Math.Abs(lineB.P2.X - lineB.P1.X) < EPSILON &&
Math.Abs(lineA.P1.X - lineB.P1.X) < EPSILON)
{
double YP1A = Math.Min(lineA.P1.Y, lineA.P2.Y);
double YP2A = Math.Max(lineA.P1.Y, lineA.P2.Y);
double YP1B = Math.Min(lineB.P1.Y, lineB.P2.Y);
double YP2B = Math.Max(lineB.P1.Y, lineB.P2.Y);
double YP1 = Math.Max(YP1A, YP1B);
double YP2 = Math.Min(YP2A, YP2B);
if (YP1 < YP2)
{
return(YP2 - YP1);
}
else
{
return(0);
}
}
else if (Math.Abs(lineA.P2.X - lineA.P1.X) < EPSILON || Math.Abs(lineB.P2.X - lineB.P1.X) < EPSILON)
{
return(0);
}
else
{
XYPoint P1A;
XYPoint P2A;
if (lineA.P1.X < lineA.P2.X)
{
P1A = lineA.P1;
P2A = lineA.P2;
}
else
{
P1A = lineA.P2;
P2A = lineA.P1;
}
XYPoint P1B;
XYPoint P2B;
if (lineB.P1.X < lineB.P2.X)
{
P1B = lineB.P1;
P2B = lineB.P2;
}
else
{
P1B = lineB.P2;
P2B = lineB.P1;
}
double alphaA = (P2A.Y - P1A.Y) / (P2A.X - P1A.X);
double betaA = -alphaA * P2A.X + P2A.Y;
double alphaB = (P2B.Y - P1B.Y) / (P2B.X - P1B.X);
double betaB = -alphaA * P2B.X + P2B.Y;
if (Math.Abs(alphaA - alphaB) < EPSILON && Math.Abs(betaA - betaB) < EPSILON)
{
double x1 = Math.Max(P1A.X, P1B.X);
double x2 = Math.Min(P2A.X, P2B.X);
if (x1 < x2)
{
XYLine line = new XYLine(x1, alphaA * x1 + betaA, x2, alphaA * x2 + betaA);
return(line.GetLength());
}
else
{
return(0);
}
}
else
{
return(0);
}
}
}
//=========================================================================================
//CalculateIntersectionPoint(XYLine line1, XYLine line2) : XYPoint
//=========================================================================================
/// <summary>
/// OverLoad of CalculateIntersectionPoint(XYPoint p1, XYPoint p2, XYPoint p3, XYPoint p4)
/// </summary>
/// <param name="line1">First line</param>
/// <param name="line2">Second line</param>
/// <returns>Intersection point</returns>
public static XYPoint CalculateIntersectionPoint(XYLine line1, XYLine line2)
{
return(CalculateIntersectionPoint(line1.P1, line1.P2, line2.P1, line2.P2));
}
//===============================================================================================
//DoLineSegmentsIntersect(XYLine line1, XYLine line2) : bool
//===============================================================================================
/// <summary>
/// OverLoad of DoLineSegmentsIntersect(x1, y1, x2, y2, x3, y3, x4, y4)
/// </summary>
/// <param name="line1">First line</param>
/// <param name="line2">Second line</param>
/// <returns>true if the line segmenst intersects otherwise false</returns>
public static bool DoLineSegmentsIntersect(XYLine line1, XYLine line2)
{
return
(DoLineSegmentsIntersect(line1.P1.X, line1.P1.Y, line1.P2.X, line1.P2.Y, line2.P1.X, line2.P1.Y, line2.P2.X,
line2.P2.Y));
}
