[飞马系列] 个人的第一个F# JIG代码——截断线绘制

//本文参照了才鸟兄的五角星例子、KEAN的螺旋线例子和AUTODESK公司的椭圆JIG例子
//在此对他们表示衷心的感谢
//by qjchen@gmail.com 华南理工大学 2010.08.10
module File1_mod.Commands
//引入一些空间，类似C#的using
open System
open Autodesk.AutoCAD.ApplicationServices
open Autodesk.AutoCAD.DatabaseServices
open Autodesk.AutoCAD.EditorInput
open Autodesk.AutoCAD.Geometry
open Autodesk.AutoCAD.GraphicsInterface
open Autodesk.AutoCAD.Runtime
//根据才鸟兄实体书中的例子编写函数，仿LISP的polar
let PolarPoint (basePt:Point2d) (angle:double) (distance:double):Point2d=
    let point = Point2d(basePt.X+distance*Math.Cos angle,basePt.Y+distance*Math.Sin angle)
    point
//Ang2Rad,仿才鸟兄的函数，不过才鸟兄写成了rad2ang，或许是笔误？
let Ang2Rad (angle:double) =
    let rad=angle*Math.PI/180.0
    rad
//定义一个继承于DrawJig的JdxJig类
type JdxJig() as this = class
  inherit DrawJig()
  //此处定义的两个变量，一个来自于jdx的初始赋值，一个来自于起始点
  let mutable (_pl : Polyline) = null
  let mutable _startPt=new Point3d()
  //member是这个类中的一个函数，仿Kean函数编写
  member x.StartJig(ed:Editor,pt,pl) =
    //将之前获取的点及构造的函数赋予此两变量
    _startPt  endPt then
       //赋予起始点给p0，赋予当前移动点给p6
       let p0:Point2d = new Point2d(_startPt.X, _startPt.Y)
       let p6:Point2d = new Point2d(curPt.X, curPt.Y)
       //计算起始点和终止点的矢量和角度
       let vec:Vector2d = p6-p0
       let ang:double = vec.Angle
       //下面这几段写的真丑陋，没有一点F#简洁的特点，下一步来进行修改
       let mutable p1=new Point2d()
       let mutable p2=new Point2d()
       let mutable p3=new Point2d()
       let mutable p4=new Point2d()
       let mutable p5=new Point2d()
       let mutable p2a=new Point2d()
       let mutable p4a=new Point2d()
       let mutable d06:double = p6.GetDistanceTo(p0)
       //以下是截断线的画法，是按照1:100的比例画的，没有考虑比例问题
       if d06 ignore
    true
end
//下面是函数命令部分
[]
let jigjdx() =
  // 开始常用语句
  let doc =
    Application.DocumentManager.MdiActiveDocument
  let ed = doc.Editor
  let db = doc.Database
  // 提示选择起始点
  let startRes = ed.GetPoint("\nSelect first point: ")
  if startRes.Status = PromptStatus.OK then
    let startPt = startRes.Value
    // 创建polyline和运行jig
    let pl:Polyline = new Polyline(7)
    for i=0 to 6 do
        pl.AddVertexAt(i, Point2d(0.0,0.0),0.0,0.0,0.0)
    let jig = new JdxJig()
    let res = jig.StartJig(ed, startPt, pl)
    if res.Status = PromptStatus.OK then
      use tr =
        db.TransactionManager.StartTransaction()
      // 得到块表和块记录
      let bt =
        tr.GetObject
          (db.BlockTableId,OpenMode.ForRead)
          :?> BlockTable
      let ms =
        tr.GetObject
          (bt.[BlockTableRecord.ModelSpace],
          OpenMode.ForWrite)
          :?> BlockTableRecord
      // 把截断线加入到模型空间
      let id = ms.AppendEntity(pl)
      tr.AddNewlyCreatedDBObject(pl, true)
      tr.Commit()