public static IEnumerator <Pair <float, Point <float> > > FindIntersectionsWith(LineSegment <float> seg, IEnumerator <Point <float> > e, bool isClosedShape)
{
int i = 0;
if (e.MoveNext())
{
Point <float> first = e.Current, prev = first;
float frac;
while (e.MoveNext())
{
Point <float> cur = e.Current;
if (seg.ComputeIntersection(prev.To(cur), out frac))
{
yield return(Pair.Create(frac, seg.PointAlong(frac)));
}
prev = cur;
i++;
}
if (i > 1 && isClosedShape)
{
if (seg.ComputeIntersection(prev.To(first), out frac))
{
yield return(Pair.Create(frac, seg.PointAlong(frac)));
}
}
}
}
private void TestItsc(LineSegment<float> p, LineSegment<float> q, Point<float>? expected, float expect_pFrac, LineType pt = LineType.Segment, LineType qt = LineType.Segment)
{
float pFrac, qFrac;
bool intersected = p.ComputeIntersection(pt, out pFrac, q, qt, out qFrac);
Assert.AreEqual(expected.HasValue, intersected);
Point<float>? result = p.ComputeIntersection(pt, q, qt);
Assert.AreEqual(expected, result);
Assert.AreEqual(expect_pFrac, pFrac);
}
private DoOrUndo AttachedAnchorChanged(Anchor anchor, bool toSide)
{
PointT p0 = default(PointT), p1 = default(PointT);
List <PointT> old = null;
return(@do =>
{
IList <PointT> points = Points;
if (toSide)
{
points = points.Reverse();
}
Debug.Assert(points.Count >= 2);
if (points.Count < 2)
{
return;
}
_bbox = null;
if (@do)
{
// save undo info in either (p0, p1) or (old) for complicated cases
p0 = points[0];
p1 = points[1];
old = new List <PointT>(Points);
var newAnchor = anchor.Point;
LineSegment <float> one = newAnchor.To(newAnchor.Add(points[1].Sub(points[0]))), two;
if (points.Count > 2)
{
two = points[1].To(points[2]);
}
else
{
two = one.B.To(one.B.Add(one.B.Sub(one.A).Rot90())); // fake it
}
points[0] = newAnchor;
PointT?itsc = one.ComputeIntersection(two, LineType.Infinite), itsc2;
if (itsc != null && !(points.Count == 2 && (toSide ? _fromAnchor : _toAnchor) != null))
{
points[1] = itsc.Value;
}
else
{
itsc = points[1];
}
if (points.Count >= 3 && points[1] == points[2])
{
int remove = 1;
if (points.Count > 3)
{
int a0 = AngleMod256(points[1].Sub(points[0])), a1 = AngleMod256(points[3].Sub(points[2]));
if ((a0 & 127) == (a1 & 127))
{
remove = 2;
}
}
points.RemoveRange(1, remove);
}
else if (points.Count >= 4 && (itsc2 = points[0].To(points[1]).ComputeIntersection(points[2].To(points[3]))) != null)
{
points.RemoveRange(1, 2);
points.Insert(1, itsc2.Value);
}
else
{
old = null; // save memory
}
}
else
{
if (old != null)
{
Points = old;
}
else
{
points[0] = p0;
points[1] = p1;
}
}
});
}
