带状地形图，根据多段线，生成A3的图框

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带状地形图，根据多段线，生成A3的图框

// Standard .NET namespaces
using System;
using System.Collections.Generic;

// Main AutoCAD namespaces
using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
using Dreambuild.AutoCAD;

[assembly: CommandClass(typeof(Sample.App))]
namespace Sample
{
    public class App
    {
        /// <summary>
        /// 生成：图框
        /// 线路生成斜框
        /// </summary>
        [CommandMethod("tk")]
        public void Xlscxk()
        {
            var id = Interaction.GetEntity("\n请选择道路中心线：", typeof(Polyline));
            if (id == ObjectId.Null)
            {
                Interaction.WriteLine("您取消了选择。");
                return;
            }

            // 定义A3的尺寸。长 a 宽 b
            double a = 420, b = 297;
            // 定义起点
            Point2d ps = Point2d.Origin;
            ObjectId pid = ObjectId.Null;
            // 第几个图框
            int index = 1;

            // 工具 id 读取对象
            var poly = id.QOpenForRead<Polyline>();
            // 遍历对象
            for (int i = 0; i <= poly.EndParam; i++)
            {
                var pe = poly.GetPoint2dAt(i);
                if (ps != Point2d.Origin)
                {
                    // 如果点在上一个多边形中，就跳过
                    if (!ObjectId.Null.Equals(pid))
                    {
                        var pl = pid.QOpenForRead<Polyline>();
                        if (pl.IsPointIn(pe.ToPoint3d()))
                        {
                            ps = pe;
                            continue;
                        }
                    }

                    //; 计算两个点之间的 x 轴的夹角
                    var alpha = ps.GetVectorTo(pe).Angle;
                    //; 计算两个点之间的距离
                    var dstc = ps.GetDistanceTo(pe);
                    //; 定义 nn 循环的个数
                    var nn = Math.Ceiling(dstc / a);

                    var pa = PolarPoints(ps, alpha + Math.PI / 2, b / 2);
                    for (int j = 0; j < nn; j++)
                    {
                        var pb = PolarPoints(pa, alpha, a);
                        var pc = PolarPoints(pa, alpha - Math.PI / 2, b);
                        var pd = PolarPoints(pc, alpha, a);

                        pid = Draw.Pline(new List<Point3d>
                        {
                            pa.ToPoint3d(),
                            pb.ToPoint3d(),
                            pd.ToPoint3d(),
                            pc.ToPoint3d(),
                            pa.ToPoint3d()
                        });
                        // 把对象放到 图框图层中
                        pid.SetLayer("tkLayer");

                        index++;

                        // 重新计算起点
                        pa = PolarPoints(pa, alpha, a);
                    }
                }

                ps = pe;
            }
        }

        private readonly Document _doc = Application.DocumentManager.MdiActiveDocument;
        private string layoutName = "TestLayout";


        static Point2d PolarPoints(Point2d pPt, double dAng, double dDist)
        {
            return new Point2d(pPt.X + dDist * Math.Cos(dAng),
                pPt.Y + dDist * Math.Sin(dAng));
        }

        static Point3d PolarPoints(Point3d pPt, double dAng, double dDist)
        {
            return new Point3d(pPt.X + dDist * Math.Cos(dAng),
                pPt.Y + dDist * Math.Sin(dAng),
                pPt.Z);
        }

        private void CreateLayout()
        {
            // 创建布局
            var layout = LayoutManager.Current.CreateLayout(layoutName).QOpenForRead<Layout>();
            Interaction.WriteLine($"创建布局 {layout.LayoutName} 成功！");

            // 切换布局，目的是激活
            LayoutManager.Current.CurrentLayout = layoutName;
        }

        private Viewport GetViewport(int n)
        {
            // 每行几个
            var numPerline = 5m;
            // 计算行号
            var rowNum = (double)Math.Ceiling(n / numPerline);
            // 计算列号
            var colNum = Math.Ceiling(n % numPerline) != 0m
                ? (double)Math.Ceiling(n % numPerline)
                : (double)numPerline;

            //  定义：长、宽、间隔
            double a = 285, b = 200, c = 50;

            //// 可用的左上方原点坐标
            double orginX = -1400, orginY = 600;

            double cx = orginX + a / 2 +
                        // 第几列
                        ((a + c) * (colNum - 1)); ;
            double cy = orginY - b / 2 -
                        // 第几行
                        ((b + c) * (rowNum - 1)); ;

            //创建视口
            Viewport vp = new Viewport
            {
                CenterPoint = new Point3d(cx, cy, 0),
                Width = a,
                Height = b
            };

            return vp;
        }


        /// </summary>
        [CommandMethod("bj")]
        async public void bj()
        {
            CreateLayout();

            // 切换到Paper空间布局
            Application.SetSystemVariable("TILEMODE", 0);
            _doc.Editor.SwitchToPaperSpace();

            Database acCurDB = _doc.Database;
            using (Transaction acTrans = acCurDB.TransactionManager.StartTransaction())
            {
                LayerTable layertb = acTrans.GetObject(acCurDB.LayerTableId, OpenMode.ForRead) as LayerTable;
                LayerTableRecord lyrbRecord = acTrans.GetObject(layertb["tkLayer"], OpenMode.ForWrite) as LayerTableRecord;

                // 图框
                List<Entity> tkList = new List<Entity>();

                //以读模式打开块表
                BlockTable bt = acTrans.GetObject(acCurDB.BlockTableId, OpenMode.ForRead) as BlockTable;
                foreach (ObjectId btrid in bt)
                {
                    BlockTableRecord btRecord = acTrans.GetObject(btrid, OpenMode.ForRead) as BlockTableRecord;
                    foreach (ObjectId eid in btRecord)  //遍历块表记录
                    {
                        Entity ent = acTrans.GetObject(eid, OpenMode.ForRead) as Entity;
                        if (ent != null && ent.LayerId == lyrbRecord.ObjectId)
                        {
                            tkList.Add(ent);
                        }
                    }
                }

                //以写模式打开块表记录Paper空间
                BlockTableRecord acBlkTbRecord = acTrans.GetObject(bt[BlockTableRecord.PaperSpace], OpenMode.ForWrite) as BlockTableRecord;
                Viewport vp;
                for (int i = 0; i < tkList.Count; i++)
                {
                    Polyline pl = tkList[i] as Polyline;

                    vp = GetViewport(i + 1);  //创建一个视口对象

                    // 添加新对象到块表记录和事务
                    acBlkTbRecord.AppendEntity(vp);
                    acTrans.AddNewlyCreatedDBObject(vp, true);

                    // 注意：旋转必须在加入到块表中才能生效。
                    // 计算线框的起点
                    var p1 = pl.GetPoint2dAt(0);
                    var p2 = pl.GetPoint2dAt(1);
                    var p3 = pl.GetPoint2dAt(2);
                    var p4 = pl.GetPoint2dAt(3);

                    // 计算平移
                    var pMin = pl.GeometricExtents.MinPoint;
                    var pMax = pl.GeometricExtents.MaxPoint;

                    // 中心点为对角线
                    var pCenter = new Point3d((p1.X + p3.X) / 2, (p1.Y + p3.Y) / 2, 0);

                    var width = p1.GetDistanceTo(p2);
                    var height = p2.GetDistanceTo(p3);

                    vp.UpgradeOpen();
                    vp.Visible = true;
                    vp.GridOn = true;

                    // 激活
                    vp.On = true;

                    // angle 是弧度
                    var alpha = (360 - p1.GetVectorTo(p2).Angle * (180 / Math.PI)) * (Math.PI / 180);
                    vp.TwistAngle = alpha;

                    // 设置中心点和高度，确定框的大小和位置 
                    vp.ViewCenter = pCenter.ToPoint2d().TransformBy(Matrix2d.Rotation(alpha, Point2d.Origin));
                    vp.ViewHeight = height;

                    Interaction.WriteLine($"{i + 1}: {p1.X},{p1.Y} {p3.X},{p3.Y}");

                    vp.DowngradeOpen();
                    vp.UpdateDisplay();

                    _doc.Editor.UpdateScreen();
                }

                acTrans.Commit();
            }
        }
    }
}