public void Cut(Pnt segStart, Pnt segLine, double offset, ref double tMin,
ref double tMax)
{
Pnt near0 = _p0 - segStart;
double offset0 = SegmentUtils.GetOffset(near0, segLine);
double along0 = SegmentUtils.GetAlongFraction(near0, segLine);
Pnt near1 = _p1 - segStart;
double offset1 = SegmentUtils.GetOffset(near1, segLine);
double along1 = SegmentUtils.GetAlongFraction(near1, segLine);
if (Math.Abs(offset0) <= offset)
{
double t = along0;
tMin = Math.Min(t, tMin);
tMax = Math.Max(t, tMax);
}
if (Math.Abs(offset1) <= offset)
{
double t = along1;
tMin = Math.Min(t, tMin);
tMax = Math.Max(t, tMax);
}
if ((offset0 < offset) == (offset1 > offset))
{
double f0 = offset0 - offset;
double f1 = offset1 - offset;
double sumF = Math.Abs(f0) + Math.Abs(f1);
if (sumF > 0)
{
double t = along0 + Math.Abs(f0) / sumF * (along1 - along0);
tMin = Math.Min(t, tMin);
tMax = Math.Max(t, tMax);
}
}
if (offset > 0 && (offset0 < -offset) == (offset1 > -offset))
{
double f0 = offset0 + offset;
double f1 = offset1 + offset;
double sumF = Math.Abs(f0) + Math.Abs(f1);
if (sumF > 0)
{
double t = along0 + Math.Abs(f0) / sumF * (along1 - along0);
tMin = Math.Min(t, tMin);
tMax = Math.Max(t, tMax);
}
}
}
private void CutCircle(Pnt segStart, Pnt segmentLine, double offset, ref double tMin,
ref double tMax)
{
Pnt near = _center - segStart;
double centerOffset = SegmentUtils.GetOffset(near, segmentLine);
if (Math.Abs(centerOffset) < offset)
{
double centerAlong = SegmentUtils.GetAlongFraction(near, segmentLine);
double segmentLength = Math.Sqrt(segmentLine.OrigDist2());
tMin = Math.Min(tMin, centerAlong - _radius / segmentLength);
tMax = Math.Max(tMax, centerAlong + _radius / segmentLength);
}
else if (_radius + offset > Math.Abs(centerOffset))
{
Pnt offsetCenter;
if (offset <= 0)
{
offsetCenter = _center;
}
else
{
double centerAlong = SegmentUtils.GetAlongFraction(near, segmentLine);
Pnt along = segStart + centerAlong * segmentLine;
double f = (Math.Abs(centerOffset) - offset) / Math.Abs(centerOffset);
offsetCenter = along + f * (_center - along);
}
double tCircleMin, tCircleMax;
if (SegmentUtils.CutLineCircle(segStart, segmentLine, offsetCenter,
_radius * _radius,
out tCircleMin, out tCircleMax))
{
tMin = Math.Min(tMin, tCircleMin);
tMax = Math.Max(tMax, tCircleMax);
}
}
}
private void CutArc(Pnt segStart, Pnt segmentLine, double offset, ref double tMin,
ref double tMax)
{
Pnt near = _center - segStart;
double centerOffset = SegmentUtils.GetOffset(near, segmentLine);
if (Math.Abs(centerOffset) < offset)
{
var canReturn = false;
double lineAngle = Math.Atan2(segmentLine.Y, segmentLine.X);
double centerAlong = SegmentUtils.GetAlongFraction(near, segmentLine);
double segmentLength = Math.Sqrt(segmentLine.OrigDist2());
if (IsInArcAngle(lineAngle))
{
canReturn = true;
tMax = Math.Max(tMax, centerAlong + _radius / segmentLength);
}
double reverseLineAngle = lineAngle - Math.PI;
if (IsInArcAngle(reverseLineAngle))
{
tMin = Math.Min(tMin, centerAlong - _radius / segmentLength);
if (canReturn)
{
return;
}
}
}
Pnt start = _center +
_radius * new Pnt2D(Math.Cos(StartDirection), Math.Sin(StartDirection))
- segStart;
double startOffset = SegmentUtils.GetOffset(start, segmentLine);
if (Math.Abs(startOffset) < offset)
{
double startAlong = SegmentUtils.GetAlongFraction(start, segmentLine);
tMin = Math.Min(tMin, startAlong);
tMax = Math.Max(tMax, startAlong);
}
double endDirection = StartDirection + (Angle ?? 0);
Pnt end = _center +
_radius * new Pnt2D(Math.Cos(endDirection), Math.Sin(endDirection))
- segStart;
double endOffset = SegmentUtils.GetOffset(end, segmentLine);
if (Math.Abs(endOffset) < offset)
{
double endAlong = SegmentUtils.GetAlongFraction(end, segmentLine);
tMin = Math.Min(tMin, endAlong);
tMax = Math.Max(tMax, endAlong);
}
if (_radius + offset > Math.Abs(centerOffset))
{
var segmentStarts = new List <Pnt>();
{
double segmentLength = Math.Sqrt(segmentLine.OrigDist2());
Pnt off = offset / segmentLength * new Pnt2D(-segmentLine.Y, segmentLine.X);
segmentStarts.Add(segStart + off);
segmentStarts.Add(segStart - off);
}
foreach (Pnt segmentStart in segmentStarts)
{
double tCircleMin, tCircleMax;
if (SegmentUtils.CutLineCircle(segmentStart, segmentLine, _center,
_radius * _radius,
out tCircleMin, out tCircleMax))
{
foreach (double t in new[] { tCircleMin, tCircleMax })
{
Pnt dirPnt = segmentStart + t * segmentLine - _center;
double dirAngle = Math.Atan2(dirPnt.Y, dirPnt.X);
if (IsInArcAngle(dirAngle))
{
tMin = Math.Min(tMin, t);
tMax = Math.Max(tMax, t);
}
}
}
}
}
}