/// <summary>
/// Distance between this and another straight line.
/// </summary>
/// <param name="TestLine">The test line.</param>
/// <param name="ptOnThis">The closest point on this to the other as a returned value.</param>
/// <param name="ptOnOther">The closest point on the other to this as a returned value.</param>
public double Distance(C2DLine TestLine, C2DPoint ptOnThis, C2DPoint ptOnOther)
{
C2DCircle Circle = new C2DCircle(GetCircleCentre(), Radius);
double dCircDist = Circle.Distance(TestLine, ptOnThis, ptOnOther);
double dDist = 0;
if (TestLine.IsOnRight(ptOnThis) ^ ArcOnRight)
{
// The point found isn't on this.
// This means the 2 closest points cannot be ON both lines, we must have a end point as one.
ptOnThis.Set(Line.point);
dDist = TestLine.Distance(ptOnThis, ptOnOther);
C2DPoint ptThisTemp = new C2DPoint(Line.GetPointTo());
C2DPoint ptOtherTemp = new C2DPoint();
double d2 = TestLine.Distance(ptThisTemp, ptOtherTemp);
if (d2 < dDist)
{
dDist = d2;
ptOnThis.Set(ptThisTemp);
ptOnOther.Set(ptOtherTemp);
}
// If the line was outside the circle then stop here as no need to go any further.
// This is because the closest point on this must be one of the end points.
if (dCircDist < 0)
{
double d3 = Distance(TestLine.point, ptThisTemp);
if (d3 < dDist)
{
dDist = d3;
ptOnThis.Set(ptThisTemp);
ptOnOther.Set(Line.point);
}
double d4 = Distance(TestLine.GetPointTo(), ptThisTemp);
if (d4 < dDist)
{
dDist = d4;
ptOnThis.Set(ptThisTemp);
ptOnOther.Set(Line.GetPointTo());
}
}
}
else
{
dDist = Math.Abs(dCircDist);
}
// ptOnThis.Set(ptThis);
// ptOnOther.Set(ptOther);
return(dDist);
}
/// <summary>
/// Returns the distance from this to the other line.
/// </summary>
/// <param name="Other">The Other line.</param>
/// <param name="ptOnThis">Output. The closest point on this.</param>
/// <param name="ptOnOther">Output. The closest point on the other line.</param>
public double Distance(C2DLine Other, C2DPoint ptOnThis , C2DPoint ptOnOther)
{
// First, project the other line onto this and if it falls entirely below it or
// above it then 1. There is no intersection, 2. This is closest to one end on this line.
C2DPoint ptOtherP2 = new C2DPoint(Other.GetPointTo());
C2DVector vThisP1OtherP1 = new C2DVector(point, Other.point);
C2DVector vThisP1OtherP2 = new C2DVector(point, ptOtherP2);
C2DPoint ptThisP2 = new C2DPoint(GetPointTo());
double dOtherP1Proj = vThisP1OtherP1.Dot(vector);
double dOtherP2Proj = vThisP1OtherP2.Dot(vector);
// If they are both less than 0 then the projection falls below the line.
if (dOtherP1Proj <= 0 && dOtherP2Proj <= 0)
{
ptOnThis.Set(point);
return Other.Distance(point, ptOnOther);
}
// Now modify the projection so it is the length along this line.
double dThisLength = GetLength();
dOtherP1Proj = dOtherP1Proj / dThisLength;
dOtherP2Proj = dOtherP2Proj / dThisLength;
// If the projections are both above the line then the second point is closest
if (dOtherP1Proj >= dThisLength && dOtherP2Proj >= dThisLength)
{
ptOnThis.Set(ptThisP2);
return Other.Distance( ptThisP2, ptOnOther);
}
// This hasn't worked so try the same on the other line.
C2DVector vOtherP1ThisP1 = new C2DVector (Other.point, point);
C2DVector vOtherP1ThisP2 = new C2DVector(Other.point, ptThisP2);
double dThisP1Proj = vOtherP1ThisP1.Dot(Other.vector);
double dThisP2Proj = vOtherP1ThisP2.Dot(Other.vector);
// If they are both less than 0 then the projection falls below the line.
if (dThisP1Proj <= 0 && dThisP2Proj <= 0)
{
ptOnOther.Set( Other.point);
return Distance(Other.point, ptOnThis);
}
// Now modify the projection so it is the length along this line.
double dOtherLength = Other.GetLength();
dThisP1Proj = dThisP1Proj / dOtherLength;
dThisP2Proj = dThisP2Proj / dOtherLength;
// If the projections are both above the line then the second point is closest
if (dThisP1Proj >= dOtherLength && dThisP2Proj >= dOtherLength)
{
ptOnOther.Set(ptOtherP2);
return Distance( ptOtherP2, ptOnThis);
}
// Now test for an intersection.
List<C2DPoint> IntPoint = new List<C2DPoint>();
bool B1 = true, B2 = true;
if (this.Crosses(Other, IntPoint,ref B1, ref B2, false))
{
ptOnOther.Set(IntPoint[0]);
ptOnThis.Set(IntPoint[0]);
return 0;
}
// Otherwise, there MUST be a point projection on one of the lines otherwise both
// lines project on either side of each other which is impossible.
// So find the distances to all these projections and take the minimum.
double dDist = 0;
double dMinDist = 0;
bool bSet = false;
C2DPoint ptOnThisTemp = new C2DPoint();
C2DPoint ptOnOtherTemp = new C2DPoint();
// Is the other lines first point projected on this?
if (dOtherP1Proj >= 0 && dOtherP1Proj <= dThisLength)
{
// If so find the point on this line and get distance to it.
double dFactor = dOtherP1Proj / dThisLength;
ptOnThisTemp.Set(new C2DPoint(point.x + vector.i * dFactor,
point.y + vector.j * dFactor) );
dMinDist = Other.point.Distance(ptOnThisTemp);
bSet = true;
ptOnOther.Set(Other.point);
ptOnThis.Set(ptOnThisTemp);
}
// Is the other lines second point projected onto this?
if (dOtherP2Proj >= 0 && dOtherP2Proj <= dThisLength)
{
// If so find the point on this and then the distance. Is it less?
double dFactor = dOtherP2Proj / dThisLength;
ptOnThisTemp.Set( new C2DPoint(point.x + vector.i * dFactor,
point.y + vector.j * dFactor) );
dDist = ptOtherP2.Distance(ptOnThisTemp);
if (!bSet || dDist < dMinDist)
{
ptOnOther.Set(ptOtherP2);
ptOnThis.Set(ptOnThisTemp);
dMinDist = dDist;
bSet = true;
}
}
// Is the first point on this projected onto the other line?
if (dThisP1Proj >= 0 && dThisP1Proj <= dOtherLength)
{
// If so find the point and the distance. Is it less?
double dFactor = dThisP1Proj / dOtherLength;
ptOnOtherTemp.Set( new C2DPoint(Other.point.x + Other.vector.i * dFactor,
Other.point.y + Other.vector.j * dFactor));
dDist = point.Distance(ptOnOtherTemp);
if (!bSet || dDist < dMinDist)
{
ptOnThis.Set(point);
ptOnOther.Set(ptOnOtherTemp);
dMinDist = dDist;
bSet = true;
}
}
// Is the second point on this projected onto the other line?
if (dThisP2Proj >= 0 && dThisP2Proj <= dOtherLength)
{
// If so find the point and the distance. Is it less?
double dFactor = dThisP2Proj / dOtherLength;
ptOnOtherTemp.Set( new C2DPoint(Other.point.x + Other.vector.i * dFactor,
Other.point.y + Other.vector.j * dFactor));
dDist = ptThisP2.Distance(ptOnOtherTemp);
if (!bSet || dDist < dMinDist)
{
ptOnThis.Set(ptThisP2);
ptOnOther.Set(ptOnOtherTemp);
dMinDist = dDist;
bSet = true;
}
}
Debug.Assert( bSet );
// Now return the minimum distance
return dMinDist;
}
/// <summary>
/// Distance to a point.
/// </summary>
/// <param name="ptTest">The test point.</param>
/// <param name="ptOnThis">Output. The closest point on the triangle.</param>
public double Distance(C2DPoint ptTest, C2DPoint ptOnThis)
{
double dArea = GetAreaSigned();
bool BTemp = true;
// Construct the lines.
C2DLine Line12 = new C2DLine(P1, P2);
C2DLine Line23 = new C2DLine(P2, P3);
C2DLine Line31 = new C2DLine(P3, P1);
if (dArea == 0)
{
// Colinear so find the biggest line and return the distance from that
double d1 = Line12.GetLength();
double d2 = Line23.GetLength();
double d3 = Line31.GetLength();
if (d1 > d2 && d1 > d3)
return Line12.Distance(ptTest, ptOnThis);
else if (d2 > d3)
return Line23.Distance(ptTest, ptOnThis);
else
return Line31.Distance(ptTest, ptOnThis);
}
// Find out it the triangle is clockwise or not.
bool bClockwise = dArea < 0;
// Set up some pointers to record the lines that the point is "above", "above" meaning that the
// point is on the opposite side of the line to the rest of the triangle
C2DLine LineAbove1 = null;
C2DLine LineAbove2 = null;
// Find out which Lines have the point above.
if ( Line12.IsOnRight( ptTest ) ^ bClockwise ) // if the pt is on the opposite side to the triangle
LineAbove1 = Line12;
if ( Line23.IsOnRight( ptTest ) ^ bClockwise)
{
if (LineAbove1 != null)
LineAbove2 = Line23;
else
LineAbove1 = Line23;
}
if ( Line31.IsOnRight( ptTest ) ^ bClockwise)
{
if (LineAbove1 != null)
{
// We can't have all the lines with the point above.
Debug.Assert(LineAbove2 != null);
LineAbove2 = Line31;
}
else
LineAbove1 = Line31;
}
// Check for containment (if there isn't a single line that its above then it must be inside)
if (LineAbove1 == null)
{
// Pt inside so project onto all the lines and find the closest projection (there must be one).
// Set up a record of the point projection on the lines.
C2DPoint ptOnLine = new C2DPoint();
bool bSet = false;
double dMinDist = 0;
if (ptTest.ProjectsOnLine(Line12, ptOnLine, ref BTemp))
{
dMinDist = ptTest.Distance(ptOnLine);
ptOnThis.Set(ptOnLine);
bSet = true;
}
if (ptTest.ProjectsOnLine(Line23, ptOnLine, ref BTemp))
{
double dDist = ptTest.Distance(ptOnLine);
if (!bSet || dDist < dMinDist)
{
dMinDist = dDist;
ptOnThis.Set(ptOnLine);
bSet = true;
}
}
if (ptTest.ProjectsOnLine(Line31, ptOnLine, ref BTemp))
{
double dDist = ptTest.Distance(ptOnLine);
if (!bSet || dDist < dMinDist)
{
dMinDist = dDist;
ptOnThis.Set(ptOnLine);
bSet = true;
}
}
Debug.Assert(bSet);
return -dMinDist; //-ve if inside
}
else if (LineAbove2 == null)
{
// it is only above 1 of the lines so simply return the distance to that line
return LineAbove1.Distance(ptTest, ptOnThis);
}
else
{
// It's above 2 lines so first check them both for projection. Can only be projected on 1.
// If the point can be projected onto the line then that's the closest point.
C2DPoint ptOnLine = new C2DPoint();
if (ptTest.ProjectsOnLine(LineAbove1, ptOnLine, ref BTemp))
{
ptOnThis = ptOnLine;
return ptOnLine.Distance(ptTest);
}
else if (ptTest.ProjectsOnLine(LineAbove2, ptOnLine, ref BTemp))
{
ptOnThis = ptOnLine;
return ptOnLine.Distance(ptTest);
}
else
{
// The point doesn't project onto either line so find the closest point
if (LineAbove1 == Line12)
{
if (LineAbove2 == Line23)
{
ptOnThis = P2;
return ptTest.Distance(P2);
}
else
{
ptOnThis = P1;
return ptTest.Distance(P1);
}
}
else
{
ptOnThis = P3;
return ptTest.Distance(P3);
}
}
}
}
/// <summary>
/// Distance to a point.
/// </summary>
/// <param name="ptTest">The test point.</param>
/// <param name="ptOnThis">Output. The closest point on the triangle.</param>
public double Distance(C2DPoint ptTest, C2DPoint ptOnThis)
{
var dArea = GetAreaSigned();
var BTemp = true;
// Construct the lines.
var Line12 = new C2DLine(P1, P2);
var Line23 = new C2DLine(P2, P3);
var Line31 = new C2DLine(P3, P1);
if (dArea == 0)
{
// Colinear so find the biggest line and return the distance from that
var d1 = Line12.GetLength();
var d2 = Line23.GetLength();
var d3 = Line31.GetLength();
if (d1 > d2 && d1 > d3)
{
return(Line12.Distance(ptTest, ptOnThis));
}
else if (d2 > d3)
{
return(Line23.Distance(ptTest, ptOnThis));
}
else
{
return(Line31.Distance(ptTest, ptOnThis));
}
}
// Find out it the triangle is clockwise or not.
var bClockwise = dArea < 0;
// Set up some pointers to record the lines that the point is "above", "above" meaning that the
// point is on the opposite side of the line to the rest of the triangle
C2DLine LineAbove1 = null;
C2DLine LineAbove2 = null;
// Find out which Lines have the point above.
if (Line12.IsOnRight(ptTest) ^ bClockwise) // if the pt is on the opposite side to the triangle
{
LineAbove1 = Line12;
}
if (Line23.IsOnRight(ptTest) ^ bClockwise)
{
if (LineAbove1 != null)
{
LineAbove2 = Line23;
}
else
{
LineAbove1 = Line23;
}
}
if (Line31.IsOnRight(ptTest) ^ bClockwise)
{
if (LineAbove1 != null)
{
// We can't have all the lines with the point above.
Debug.Assert(LineAbove2 != null);
LineAbove2 = Line31;
}
else
{
LineAbove1 = Line31;
}
}
// Check for containment (if there isn't a single line that its above then it must be inside)
if (LineAbove1 == null)
{
// Pt inside so project onto all the lines and find the closest projection (there must be one).
// Set up a record of the point projection on the lines.
var ptOnLine = new C2DPoint();
var bSet = false;
double dMinDist = 0;
if (ptTest.ProjectsOnLine(Line12, ptOnLine, ref BTemp))
{
dMinDist = ptTest.Distance(ptOnLine);
ptOnThis.Set(ptOnLine);
bSet = true;
}
if (ptTest.ProjectsOnLine(Line23, ptOnLine, ref BTemp))
{
var dDist = ptTest.Distance(ptOnLine);
if (!bSet || dDist < dMinDist)
{
dMinDist = dDist;
ptOnThis.Set(ptOnLine);
bSet = true;
}
}
if (ptTest.ProjectsOnLine(Line31, ptOnLine, ref BTemp))
{
var dDist = ptTest.Distance(ptOnLine);
if (!bSet || dDist < dMinDist)
{
dMinDist = dDist;
ptOnThis.Set(ptOnLine);
bSet = true;
}
}
Debug.Assert(bSet);
return(-dMinDist); //-ve if inside
}
else if (LineAbove2 == null)
{
// it is only above 1 of the lines so simply return the distance to that line
return(LineAbove1.Distance(ptTest, ptOnThis));
}
else
{
// It's above 2 lines so first check them both for projection. Can only be projected on 1.
// If the point can be projected onto the line then that's the closest point.
var ptOnLine = new C2DPoint();
if (ptTest.ProjectsOnLine(LineAbove1, ptOnLine, ref BTemp))
{
ptOnThis = ptOnLine;
return(ptOnLine.Distance(ptTest));
}
else if (ptTest.ProjectsOnLine(LineAbove2, ptOnLine, ref BTemp))
{
ptOnThis = ptOnLine;
return(ptOnLine.Distance(ptTest));
}
else
{
// The point doesn't project onto either line so find the closest point
if (LineAbove1 == Line12)
{
if (LineAbove2 == Line23)
{
ptOnThis = P2;
return(ptTest.Distance(P2));
}
else
{
ptOnThis = P1;
return(ptTest.Distance(P1));
}
}
else
{
ptOnThis = P3;
return(ptTest.Distance(P3));
}
}
}
}
/// <summary>
/// Returns the distance from this to the other line.
/// </summary>
/// <param name="Other">The Other line.</param>
/// <param name="ptOnThis">Output. The closest point on this.</param>
/// <param name="ptOnOther">Output. The closest point on the other line.</param>
public double Distance(C2DLine Other, C2DPoint ptOnThis, C2DPoint ptOnOther)
{
// First, project the other line onto this and if it falls entirely below it or
// above it then 1. There is no intersection, 2. This is closest to one end on this line.
var ptOtherP2 = new C2DPoint(Other.GetPointTo());
var vThisP1OtherP1 = new C2DVector(point, Other.point);
var vThisP1OtherP2 = new C2DVector(point, ptOtherP2);
var ptThisP2 = new C2DPoint(GetPointTo());
var dOtherP1Proj = vThisP1OtherP1.Dot(vector);
var dOtherP2Proj = vThisP1OtherP2.Dot(vector);
// If they are both less than 0 then the projection falls below the line.
if (dOtherP1Proj <= 0 && dOtherP2Proj <= 0)
{
ptOnThis.Set(point);
return(Other.Distance(point, ptOnOther));
}
// Now modify the projection so it is the length along this line.
var dThisLength = GetLength();
dOtherP1Proj = dOtherP1Proj / dThisLength;
dOtherP2Proj = dOtherP2Proj / dThisLength;
// If the projections are both above the line then the second point is closest
if (dOtherP1Proj >= dThisLength && dOtherP2Proj >= dThisLength)
{
ptOnThis.Set(ptThisP2);
return(Other.Distance(ptThisP2, ptOnOther));
}
// This hasn't worked so try the same on the other line.
var vOtherP1ThisP1 = new C2DVector(Other.point, point);
var vOtherP1ThisP2 = new C2DVector(Other.point, ptThisP2);
var dThisP1Proj = vOtherP1ThisP1.Dot(Other.vector);
var dThisP2Proj = vOtherP1ThisP2.Dot(Other.vector);
// If they are both less than 0 then the projection falls below the line.
if (dThisP1Proj <= 0 && dThisP2Proj <= 0)
{
ptOnOther.Set(Other.point);
return(Distance(Other.point, ptOnThis));
}
// Now modify the projection so it is the length along this line.
var dOtherLength = Other.GetLength();
dThisP1Proj = dThisP1Proj / dOtherLength;
dThisP2Proj = dThisP2Proj / dOtherLength;
// If the projections are both above the line then the second point is closest
if (dThisP1Proj >= dOtherLength && dThisP2Proj >= dOtherLength)
{
ptOnOther.Set(ptOtherP2);
return(Distance(ptOtherP2, ptOnThis));
}
// Now test for an intersection.
var IntPoint = new List <C2DPoint>();
bool B1 = true, B2 = true;
if (this.Crosses(Other, IntPoint, ref B1, ref B2, false))
{
ptOnOther.Set(IntPoint[0]);
ptOnThis.Set(IntPoint[0]);
return(0);
}
// Otherwise, there MUST be a point projection on one of the lines otherwise both
// lines project on either side of each other which is impossible.
// So find the distances to all these projections and take the minimum.
double dDist = 0;
double dMinDist = 0;
var bSet = false;
var ptOnThisTemp = new C2DPoint();
var ptOnOtherTemp = new C2DPoint();
// Is the other lines first point projected on this?
if (dOtherP1Proj >= 0 && dOtherP1Proj <= dThisLength)
{
// If so find the point on this line and get distance to it.
var dFactor = dOtherP1Proj / dThisLength;
ptOnThisTemp.Set(new C2DPoint(point.x + vector.i * dFactor,
point.y + vector.j * dFactor));
dMinDist = Other.point.Distance(ptOnThisTemp);
bSet = true;
ptOnOther.Set(Other.point);
ptOnThis.Set(ptOnThisTemp);
}
// Is the other lines second point projected onto this?
if (dOtherP2Proj >= 0 && dOtherP2Proj <= dThisLength)
{
// If so find the point on this and then the distance. Is it less?
var dFactor = dOtherP2Proj / dThisLength;
ptOnThisTemp.Set(new C2DPoint(point.x + vector.i * dFactor,
point.y + vector.j * dFactor));
dDist = ptOtherP2.Distance(ptOnThisTemp);
if (!bSet || dDist < dMinDist)
{
ptOnOther.Set(ptOtherP2);
ptOnThis.Set(ptOnThisTemp);
dMinDist = dDist;
bSet = true;
}
}
// Is the first point on this projected onto the other line?
if (dThisP1Proj >= 0 && dThisP1Proj <= dOtherLength)
{
// If so find the point and the distance. Is it less?
var dFactor = dThisP1Proj / dOtherLength;
ptOnOtherTemp.Set(new C2DPoint(Other.point.x + Other.vector.i * dFactor,
Other.point.y + Other.vector.j * dFactor));
dDist = point.Distance(ptOnOtherTemp);
if (!bSet || dDist < dMinDist)
{
ptOnThis.Set(point);
ptOnOther.Set(ptOnOtherTemp);
dMinDist = dDist;
bSet = true;
}
}
// Is the second point on this projected onto the other line?
if (dThisP2Proj >= 0 && dThisP2Proj <= dOtherLength)
{
// If so find the point and the distance. Is it less?
var dFactor = dThisP2Proj / dOtherLength;
ptOnOtherTemp.Set(new C2DPoint(Other.point.x + Other.vector.i * dFactor,
Other.point.y + Other.vector.j * dFactor));
dDist = ptThisP2.Distance(ptOnOtherTemp);
if (!bSet || dDist < dMinDist)
{
ptOnThis.Set(ptThisP2);
ptOnOther.Set(ptOnOtherTemp);
dMinDist = dDist;
bSet = true;
}
}
Debug.Assert(bSet);
// Now return the minimum distance
return(dMinDist);
}
/// <summary>
/// Distance between this and another straight line.
/// </summary>
/// <param name="TestLine">The test line.</param>
/// <param name="ptOnThis">The closest point on this to the other as a returned value.</param>
/// <param name="ptOnOther">The closest point on the other to this as a returned value.</param>
public double Distance(C2DLine TestLine, C2DPoint ptOnThis, C2DPoint ptOnOther)
{
C2DCircle Circle = new C2DCircle( GetCircleCentre(), Radius);
double dCircDist = Circle.Distance(TestLine, ptOnThis, ptOnOther);
double dDist = 0;
if (TestLine.IsOnRight(ptOnThis) ^ ArcOnRight)
{
// The point found isn't on this.
// This means the 2 closest points cannot be ON both lines, we must have a end point as one.
ptOnThis.Set(Line.point);
dDist = TestLine.Distance(ptOnThis, ptOnOther);
C2DPoint ptThisTemp = new C2DPoint(Line.GetPointTo());
C2DPoint ptOtherTemp = new C2DPoint();
double d2 = TestLine.Distance(ptThisTemp, ptOtherTemp);
if (d2 < dDist)
{
dDist = d2;
ptOnThis.Set(ptThisTemp);
ptOnOther.Set(ptOtherTemp);
}
// If the line was outside the circle then stop here as no need to go any further.
// This is because the closest point on this must be one of the end points.
if (dCircDist < 0)
{
double d3 = Distance(TestLine.point, ptThisTemp);
if (d3 < dDist)
{
dDist = d3;
ptOnThis.Set(ptThisTemp);
ptOnOther.Set(Line.point);
}
double d4 = Distance(TestLine.GetPointTo(), ptThisTemp);
if (d4 < dDist)
{
dDist = d4;
ptOnThis.Set(ptThisTemp);
ptOnOther.Set(Line.GetPointTo());
}
}
}
else
{
dDist = Math.Abs(dCircDist);
}
// ptOnThis.Set(ptThis);
// ptOnOther.Set(ptOther);
return dDist;
}
