/// <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
{
IXYPoint P1A = new XYPoint();
IXYPoint P2A = new XYPoint();
if (lineA.P1.X < lineA.P2.X)
{
P1A = lineA.P1;
P2A = lineA.P2;
}
else
{
P1A = lineA.P2;
P2A = lineA.P1;
}
IXYPoint P1B = new XYPoint();
IXYPoint P2B = new XYPoint();
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;
}
}
}
/// <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
{
IXYPoint P1A = new XYPoint();
IXYPoint P2A = new XYPoint();
if (lineA.P1.X < lineA.P2.X)
{
P1A = lineA.P1;
P2A = lineA.P2;
}
else
{
P1A = lineA.P2;
P2A = lineA.P1;
}
IXYPoint P1B = new XYPoint();
IXYPoint P2B = new XYPoint();
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);
}
}
}
