private static List<Intersection> CutByLineVertical(Vertex s1, Vertex s2, LinkedList<VertexBase> linkC)
{
var crossXs = new List<Intersection>();
var x = s1.X;
List<VertexBase> shearedPolyC = linkC.ToList();
var minY = s1.Y > s2.Y ? s2.Y : s1.Y;
var maxY = s1.Y > s2.Y ? s1.Y : s2.Y;
int i = -1;
bool backToHead = false;
for (var vertex = linkC.First;
//这样回到头部的线也可以正常被切到
vertex != null &&
((vertex.Value is Vertex && vertex.Next != null) ||
((vertex.Value is Intersection) && ((Intersection)vertex.Value).NextC != null) ||
(vertex.Value is Vertex && vertex.Next == null && !backToHead) ||
(vertex.Value is Intersection && ((Intersection)vertex.Value).NextC == null && !backToHead));
vertex = vertex.Next)
{
i++;
var c1 = shearedPolyC[i % shearedPolyC.Count];
var c2 = shearedPolyC[(i + 1)%shearedPolyC.Count];
// 重合
if (c1.X == c2.X && c1.X == x) continue;
//不相交
if (c1.X > x && c2.X > x) continue;
if (c1.X < x && c2.X < x) continue;
var y = LineCrossV(x, c1, c2);
var inters = new Intersection(x, y);
VertexBase next = null;
if ((y > minY && y < maxY) ||
(c2.X == x && y == minY) ||
(c2.X == x && y == maxY) ||
(y == minY && c1.X != x && c2.X != x) ||
(y == maxY && c1.X != x && c2.X != x))
{
inters.Name = "I" + Counter.Default.Val++;
if (vertex.Next == null)
{
backToHead = true;
next = linkC.First.Value;
}
else
{
next = vertex.Next.Value;
}
WindowLog.Default.Log("切割C的边{0}{1}得到交点{2}", vertex.Value.Name,
next.Name, inters.Name);
inters.NextC = next;
if (vertex.Value is Vertex)
(vertex.Value as Vertex).Next = inters;
else if (vertex.Value is Intersection)
(vertex.Value as Intersection).NextC = inters;
linkC.AddAfter(vertex, inters);
vertex = vertex.Next;
crossXs.Add(inters);
}
if (backToHead)
break;
#region log
var cLinkSb = new StringBuilder();
var v = linkC.First.Value;
while (v != null)
{
cLinkSb.Append(v.Name);
if (v is Intersection)
{
var curr = v as Intersection;
next = curr.NextC;
}
else if (v is Vertex)
{
var curr = v as Vertex;
next = curr.Next;
}
if (next.Equals(linkC.First.Value))
{
break;
}
v = next;
cLinkSb.Append("->");
}
WindowLog.Default.Log("C链表：" + cLinkSb);
#endregion
}
return crossXs;
}
private void MoveOver(object sender, MouseEventArgs e)
{
_cross.Visible = false;
var point = e.GetPosition(Canvas);
PointVec.Text = "坐标位置：" + point.X + "," + point.Y;
var newVector = new Vertex(point.X, point.Y);
if (Keyboard.IsKeyDown(Key.LeftShift) && (_drawingPolygonC || _drawingPolygonS))
{
VertexBase pointPre = null;
if (_drawingPolygonS)
pointPre = _polyS.PointList[_polygonSVertexNum - 2];
else if (_drawingPolygonC)
pointPre = _polyC.PointList[_polygonCVertexNum - 2];
var dx = pointPre.X - point.X;
double tan = 0;
if (dx != 0)
{
var dy = pointPre.Y - point.Y;
tan = Math.Abs(dy / dx);
}
else
{
tan = double.MaxValue;
}
if (tan <= 1)
newVector = new Vertex(point.X, (double)pointPre.Y);
else if (tan > 1)
{
newVector = new Vertex((double)pointPre.X, point.Y);
}
}
//抓去最近点
Point nearestPoint = new Point();
bool hasNearestSite = false;
if (_drawingPolygonS)
hasNearestSite = IsCloseToPolygon(point, _polyC, ref nearestPoint);
else if (_drawingPolygonC)
hasNearestSite = IsCloseToPolygon(point, _polyS, ref nearestPoint);
if (hasNearestSite)
{
_cross.Center = nearestPoint;
_cross.Visible = true;
var screenPoint = Canvas.PointToScreen(nearestPoint);
SetCursorPos((int)screenPoint.X,(int)screenPoint.Y);
}
if (_drawingPolygonS && _polygonSVertexNum > 0)
{
_polyS.PointList[_polygonSVertexNum - 1].SetXY(newVector.X, newVector.Y);
_polyS.Render(Canvas);
}
if (_drawingPolygonC && _polygonCVertexNum > 0)
{
_polyC.PointList[_polygonCVertexNum - 1].SetXY(newVector.X, newVector.Y);
_polyC.Render(Canvas);
}
}
/// <summary>
/// 用实体多边形S的边切割切割多边形C，并插入交点到C中
/// </summary>
/// <param name="s1"></param>
/// <param name="s2"></param>
/// <param name="linkC"></param>
/// <returns></returns>
private static List<Intersection> CutByLine(Vertex s1, Vertex s2, LinkedList<VertexBase> linkC)
{
if (s1.X == s2.X)
return CutByLineVertical(s1, s2, linkC);
var crossXs = new List<Intersection>();
double slope = 0, y = s1.Y;
slope = (s2.Y - s1.Y) / (s1.X - s2.X);//s2.Y == s1.Y不单独判断，反正这里可以正常处理s2.Y == s1.Y即slope==0
var shearedPolyC = linkC.Select(r => new Vertex(r.X, r.X * slope + r.Y) as VertexBase).ToList();//为了保存错切计算的坐标
y = s1.X * slope + s1.Y;
var minX = s1.X > s2.X ? s2.X : s1.X;
var maxX = s1.X > s2.X ? s1.X : s2.X;
//LinkedListNode<VertexBase> vertex;
int i = -1;
var backToHead = false;
for (var vertex = linkC.First;
//这样回到头部的线也可以正常被切到
vertex != null &&
((vertex.Value is Vertex && vertex.Next != null) ||
((vertex.Value is Intersection) && ((Intersection)vertex.Value).NextC != null) ||
(vertex.Value is Vertex && vertex.Next == null && !backToHead) ||
(vertex.Value is Intersection && ((Intersection)vertex.Value).NextC == null && !backToHead));
vertex = vertex.Next)
{
++i;
var c1 = shearedPolyC[i % shearedPolyC.Count];
var c2 = shearedPolyC[(i + 1) % shearedPolyC.Count];
// 重合
if (c1.Y == c2.Y && c1.Y == y) continue;
//不相交
if (c1.Y > y && c2.Y > y) continue;
if (c1.Y < y && c2.Y < y) continue;
var x = LineCrossH(y, c1, c2);
var npy = y - x * slope;
var inters = new Intersection(x, npy);
VertexBase next = null;
if ((x > minX && x < maxX) ||
(c2.Y == y && x == s2.X) ||
(x == minX && c1.Y != y && c2.Y != y) ||
(x == maxX && c1.Y != y && c2.Y != y))
{
inters.Name = "I" + Counter.Default.Val++;
if (vertex.Next == null)
{
backToHead = true;
next = linkC.First.Value;
}
else
{
next = vertex.Next.Value;
}
WindowLog.Default.Log("切割C的边{0}{1}得到交点{2}", vertex.Value.Name,
next.Name, inters.Name);
inters.NextC = next;
if (vertex.Value is Vertex)
((Vertex)vertex.Value).Next = inters;
else if (vertex.Value is Intersection)
((Intersection)vertex.Value).NextC = inters;
linkC.AddAfter(vertex, inters);
vertex = vertex.Next;
crossXs.Add(inters);
}
if (backToHead)
break;
#region log
var cLinkSb = new StringBuilder();
var v = linkC.First.Value;
while (v != null)
{
cLinkSb.Append(v.Name);
if (v is Intersection)
{
var curr = v as Intersection;
next = curr.NextC;
}
else if (v is Vertex)
{
var curr = v as Vertex;
next = curr.Next;
}
if (next.Equals(linkC.First.Value))
{
break;
}
v = next;
cLinkSb.Append("->");
}
WindowLog.Default.Log("C链表：" + cLinkSb);
#endregion
}
return crossXs;
}
