/// <summary>
/// The concept of touch is simpler than the type of intersection
/// </summary>
/// <returns></returns>
/// <remarks>It turns out that we do not really need this function</remarks>
public bool IsTouch()
{
CEdge cedge1 = _CEdge1;
CEdge cedge2 = _CEdge2;
cedge1.JudgeAndSetSlope();
cedge2.JudgeAndSetSlope();
CPoint IntersectCpt = null;
//CEdge overlapcedge = null;
//CEnumIntersectionType penumIntersectionType = CEnumIntersectionType.NoNo;
if (cedge1.blnHasSlope == true && cedge2.blnHasSlope == true) //this is the normal case
{
//if (CCmpMethods.Cmp(cedge1.dblSlope, cedge2.dblSlope)==0) //parallel
if (CCmpMethods.CmpDbl_ConstVerySmall(cedge1.dblSlope, cedge2.dblSlope) == 0) //parallel
{
if (CCmpMethods.CmpDbl_CoordVerySmall(cedge1.dblYIntercept, cedge2.dblYIntercept) == 0)
{
//parallel and with the same YIntercept
return(IsTouchParralel(cedge1, cedge2, out IntersectCpt));
}
else //parallel but not with the same YIntercept
{
return(false);
}
}
else //not parallel
{
return(IsTouchNormal(cedge1, cedge2, out IntersectCpt));
}
}
else if (cedge1.blnHasSlope == true && cedge2.blnHasSlope == false)
{
return(IsTouchOneNoSlope(cedge1, cedge2, out IntersectCpt));
}
else if (cedge1.blnHasSlope == false && cedge2.blnHasSlope == true)
{
return(IsTouchOneNoSlope(cedge2, cedge1, out IntersectCpt));
}
else if (cedge1.blnHasSlope == false && cedge2.blnHasSlope == false)
{
//parallel and with the same X Coordinate
if (CCmpMethods.CmpDbl_CoordVerySmall(cedge1.FrCpt.X, cedge2.FrCpt.X) == 0)
{
return(IsTouchParralel(cedge1, cedge2, out IntersectCpt));
}
else //parallel but not with the same X Coordinate
{
return(false);
}
}
//_enumIntersectionType = penumIntersectionType;
_IntersectCpt = IntersectCpt;
//_OverlapCEdge = overlapcedge;
throw new ArgumentException("unexpected case!");
}
private List <CValPair <int, int> > HandleWithXDiff(CEdge cedge, CEdge cedgeIncrX,
double dblCellWidth, double dblCellHeight, CEnvelope pEnvelope, List <CEdge>[,] aCEdgeLtCell)
{
int intFrRow = Convert.ToInt32(Math.Truncate((cedgeIncrX.FrCpt.Y - pEnvelope.YMin) / dblCellHeight));
int intFrCol = Convert.ToInt32(Math.Truncate((cedgeIncrX.FrCpt.X - pEnvelope.XMin) / dblCellWidth));
int intToRow = Convert.ToInt32(Math.Truncate((cedgeIncrX.ToCpt.Y - pEnvelope.YMin) / dblCellHeight));
int intToCol = Convert.ToInt32(Math.Truncate((cedgeIncrX.ToCpt.X - pEnvelope.XMin) / dblCellWidth));
cedgeIncrX.JudgeAndSetSlope();
double dblYIncrement = dblCellWidth * cedgeIncrX.dblSlope;
double dblYIntersectVertical = cedgeIncrX.FrCpt.Y +
cedgeIncrX.dblSlope * (GetCellXMin(intFrCol + 1) - cedgeIncrX.FrCpt.X);
int intLastRow = intFrRow;
var intRowColVpLt = new List <CValPair <int, int> >();
//the columns before the last column
//Note that if the FrCpt and ToCpt are in the same column (i.e., intFrCol == intToCol),
//then this "for loop" will do nothing
for (int i = intFrCol; i < intToCol; i++)
{
int intRowIntersect = Convert.ToInt32(Math.Truncate((dblYIntersectVertical - pEnvelope.YMin) / dblCellHeight));
intRowColVpLt.AddRange(RecordIntoOneColumn(cedge, i, intLastRow, intRowIntersect, aCEdgeLtCell));
dblYIntersectVertical += dblYIncrement;
intLastRow = intRowIntersect;
}
//the last column.
intRowColVpLt.AddRange(RecordIntoOneColumn(cedge, intToCol, intLastRow, intToRow, aCEdgeLtCell));
return(intRowColVpLt);
}
//public void SetSlope(ref List <CEdge > CEdgeLt)
//{
// CGeoFunc.SetSlope(ref CEdgeLt);
//}
/// <summary>Detect the intesection between two edges</summary>
/// <returns >the intersection point</returns>
/// <remarks>the edges have to be set slope before using this function
/// If the two edges overlap, then the IntersectCpt is the point with larger XY coordinate of the two ends of the overlap line segment
/// </remarks>
public void DetectIntersection()
{
CEdge cedge1 = _CEdge1;
CEdge cedge2 = _CEdge2;
cedge1.JudgeAndSetSlope();
cedge2.JudgeAndSetSlope();
CPoint IntersectCpt = null;
CEdge overlapcedge = null;
CEnumIntersectionType penumIntersectionType = CEnumIntersectionType.NoNo;
if (cedge1.blnHasSlope == true && cedge2.blnHasSlope == true) //this is the normal case
{
//if (CCmpMethods.Cmp(cedge1.dblSlope, cedge2.dblSlope)==0) //parallel
if (CCmpMethods.CmpDbl_ConstVerySmall(cedge1.dblSlope, cedge2.dblSlope) == 0) //parallel
{
if (CCmpMethods.CmpDbl_CoordVerySmall(cedge1.dblYIntercept, cedge2.dblYIntercept) == 0) //parallel and with the same YIntercept
{
penumIntersectionType = DetectIntersectionParralel(cedge1, cedge2, out IntersectCpt, out overlapcedge);
}
else //parallel but not with the same YIntercept
{
penumIntersectionType = CEnumIntersectionType.NoNo;
}
}
else //not parallel
{
penumIntersectionType = DetectIntersectionNormal(cedge1, cedge2, out IntersectCpt);
}
}
else if (cedge1.blnHasSlope == true && cedge2.blnHasSlope == false)
{
penumIntersectionType = DetectIntersectionOneNoSlope(cedge1, cedge2, out IntersectCpt);
}
else if (cedge1.blnHasSlope == false && cedge2.blnHasSlope == true)
{
penumIntersectionType = DetectIntersectionOneNoSlope(cedge2, cedge1, out IntersectCpt);
penumIntersectionType = ReverseIntersectionType(penumIntersectionType);
}
else if (cedge1.blnHasSlope == false && cedge2.blnHasSlope == false)
{
if (CCmpMethods.CmpDbl_CoordVerySmall(cedge1.FrCpt.X, cedge2.FrCpt.X) == 0) //parallel and with the same X Coordinate
{
penumIntersectionType = DetectIntersectionParralel(cedge1, cedge2, out IntersectCpt, out overlapcedge);
}
else //parallel but not with the same X Coordinate
{
penumIntersectionType = CEnumIntersectionType.NoNo;
}
}
_enumIntersectionType = penumIntersectionType;
_IntersectCpt = IntersectCpt;
_OverlapCEdge = overlapcedge;
}