static bool FindTrimEndForArrowheadAtTarget(ICurve lineCurve, Arrowhead tarArrowhead, out double p)
{
//Debug.Assert((edgeGeometry.Curve.End - edgeGeometry.Curve.Start).LengthSquared > eps);
p = lineCurve.ParEnd;
if (tarArrowhead == null || tarArrowhead.Length <= ApproximateComparer.DistanceEpsilon)
{
return(true);
}
var eps = ApproximateComparer.DistanceEpsilon * ApproximateComparer.DistanceEpsilon;
var curve = lineCurve;
var arrowheadLength = tarArrowhead.Length;
Point newCurveEnd;
IList <IntersectionInfo> intersections;
int reps = 10;
do
{
reps--;
if (reps == 0)
{
return(false);
}
intersections = GetIntersectionsWithArrowheadCircle(curve, arrowheadLength, curve.End);
p = intersections.Count != 0 ? intersections.Max(x => x.Par1) : curve.ParEnd;
newCurveEnd = lineCurve[p];
arrowheadLength /= 2;
} while (((newCurveEnd - curve.Start).LengthSquared < eps || intersections.Count == 0));
//we would like to have at least something left from the curve
return(true);
}
static bool FindTrimStartForArrowheadAtSource(ICurve lineCurve, Arrowhead srcArrowhead, out double p)
{
p = 0; //does not matter
if (srcArrowhead == null || srcArrowhead.Length <= ApproximateComparer.DistanceEpsilon)
{
return(true);
}
var eps = ApproximateComparer.DistanceEpsilon * ApproximateComparer.DistanceEpsilon;
Debug.Assert((lineCurve.End - lineCurve.Start).LengthSquared > eps);
var arrowheadLength = srcArrowhead.Length;
Point newStart;
var curve = lineCurve;
IList <IntersectionInfo> intersections;
int reps = 10;
do
{
reps--;
if (reps == 0)
{
return(false);
}
intersections = GetIntersectionsWithArrowheadCircle(curve, arrowheadLength, curve.Start);
p = intersections.Count != 0 ? intersections.Min(x => x.Par1) : curve.ParStart;
newStart = curve[p];
arrowheadLength /= 2;
} while ((newStart - curve.End).LengthSquared < eps || intersections.Count == 0);
//we are checkng that something will be left from the curve
return(true);
}
public static bool CalculateArrowheads(ref ICurve lineCurve, Arrowhead srcArrowhead, Arrowhead tarArrowhead)
{
//ValidateArg.IsNotNull(edgeGeometry, "edgeGeometry");
if (srcArrowhead == null && tarArrowhead == null)
{
return(true);
}
double parStart, parEnd;
if (!FindTrimStartForArrowheadAtSource(lineCurve, srcArrowhead, out parStart))
{
return(false);
}
if (!FindTrimEndForArrowheadAtTarget(lineCurve, tarArrowhead, out parEnd))
{
return(false);
}
if (parStart > parEnd - ApproximateComparer.IntersectionEpsilon || ApproximateComparer.CloseIntersections(lineCurve[parStart], lineCurve[parEnd]))
{
return(false); //after the trim nothing would be left of the curve
}
var c = lineCurve.Trim(parStart, parEnd);
if (c == null)
{
return(false);
}
if (srcArrowhead != null)
{
srcArrowhead.TipPosition = PlaceTip(c.Start, lineCurve.Start, srcArrowhead.Offset);
}
if (tarArrowhead != null)
{
tarArrowhead.TipPosition = PlaceTip(c.End, lineCurve.End, tarArrowhead.Offset);
}
lineCurve = c;
return(true);
}
