C# 计算不规则多边形的相交/包含等关系

核心思路是使用Region的求交集和并集的结果与原始Region对比

Winform项目自带这个类库，如果使用控制台，需要先在nuget安装System.Drawing.Common

        /// <summary>
        /// 计算两个形状的关系
        /// </summary>
        /// <param name="rgn1">形状1</param>
        /// <param name="rgn2">形状2</param>
        /// <returns></returns>
        private string CalculateShapeRelationship(Region rgn1, Region rgn2)
        {
            RectangleF[] rect1 = rgn1.GetRegionScans(new Matrix());  //将形状切片
            RectangleF[] rect2 = rgn2.GetRegionScans(new Matrix());
            if (Enumerable.SequenceEqual(rect1, rect2))  //如果两个形状切片结果相同，则为重叠
                return "重叠";

            using (Region rgnIntersect = rgn1.Clone())
            {
                rgnIntersect.Intersect(rgn2);  //求交集
                RectangleF[] rectIntersect = rgnIntersect.GetRegionScans(new Matrix());//将交集切片
                if (rectIntersect.Length == 0)  //如果交集切片没有结果则两个形状没有交集
                    return "相离";
            }
            using (Region rgnUnion = rgn1.Clone())
            {
                rgnUnion.Union(rgn2);  //求并集
                RectangleF[] rectUnion = rgnUnion.GetRegionScans(new Matrix()); //将并集切片

                if (rectUnion.Length == rect1.Length)  //如果区域1和并集一样
                    return "区域1包含区域2";

                if (rectUnion.Length == rect2.Length)  //如果区域2和并集一样
                    return "区域2包含区域1";

                return "相交";  //两个都只占并集的一部分，则为相交
            }
        }