//不能出现A多边形的连接两条边的顶点在B多边形的一条边上的情况
public static List <Polygon> Union(Polygon clip, Polygon subject)
{
var ret = new List <Polygon>();
pClip = clip;
pSubject = subject;
//包围盒不相交
if (pSubject.boxRectangle.IsIntersect(pClip.boxRectangle) == false)
{
return(null);
}
//所有顶点和交点
lnClip = PolygonNodeUtil.CreateNodes(clip, false, false); //副多边形
lnSubject = PolygonNodeUtil.CreateNodes(subject, false, true); //主多边形
//插入交点
var insCnt = IntersectPoint_Union();
//生成多边形
if (insCnt > 0)
{
ret = LinkToPolygon_Union();
return(ret);
}
return(null);
}
public static List <Polygon> Cut(Polygon clip, Polygon subject)
{
var ret = new List <Polygon>();
pClip = clip;
pSubject = subject;
//包围盒不相交
if (pSubject.boxRectangle.IsIntersect(pClip.boxRectangle) == false)
{
return(null);
}
//所有顶点和交点
lnClip = PolygonNodeUtil.CreateNodes(pClip, false, false); //副多边形
lnSubject = PolygonNodeUtil.CreateNodes(pSubject, false, true); //主多边形
//插入交点
var insCnt = IntersectPoint_Cut();
//生成多边形
if (insCnt > 0)
{
ret = LinkToPolygon_Cut();
return(ret);
}
//0个交点
//要判断是否主多边形包含副多边形，如果包含，则返回副多边形
var AContainB = true;
foreach (var line in pClip.lineList)
{
if (!pSubject.Contains(line))
{
AContainB = false;
}
}
if (AContainB)
{
ret.Add(pClip);
return(ret);
}
//要判断是否副多边形包含主多边形，如果包含，则返回主多边形
var BContainA = true;
for (var i = 0; i < pSubject.lineList.Count; i++)
{
var line = pSubject.lineList[i];
if (!pClip.Contains(line))
{
BContainA = false;
}
}
if (BContainA)
{
ret.Add(pSubject);
return(ret);
}
return(null);
}