AutoCAD .Net二次开发之JIG动态绘制详解

AutoCAD平台动态绘制分两种，单实体绘制EntityJig和多实体绘制DrawJig，需要自己自定义类去继承。(本人的理解全放在了代码注释中,请详看注释)

EntityJig（单实体绘制）

class MyLineJig : EntityJig//使用此基类来实现动态绘制只可以绘制一个实体{//基类EntityJig中有一个关键的成员变量Entity,也就是要绘制到模型空间的临时图形，在绘制完成后将其添加到模型空间以及数据库，既完成了动态绘制public MyLineJig(Point3d _basePt) : base(new Line(_basePt, _basePt))//在构造之前调用基类构造为基类成员Entity初始化{m_AcquirePoint = _basePt;}public static bool StartDrag()//调用此方法开始绘制{Document doc = Application.DocumentManager.MdiActiveDocument;Point3d startPt = Point3d.Origin;PromptStatus promptStatus = GetPoint("", ref startPt);//需自己实现（获取用户输入点）if (promptStatus != PromptStatus.OK)return false;MyLineJig lineJig = new MyLineJig(startPt);PromptResult PR = doc.Editor.Drag(lineJig);//开始绘制if (PR.Status != PromptStatus.OK)return false;AppendEntityToModalSpace(doc, lineJig.Entity);//需自己实现（将实体添加进模型空间）return true;}protected override SamplerStatus Sampler(JigPrompts prompts)//提取输入数据并处理(鼠标移动时一定频率调用){JigPromptPointOptions JPPO = new JigPromptPointOptions();//定义点绘制的配置类JPPO.Message = "\n选择点";PromptPointResult PR = prompts.AcquirePoint(JPPO);//当鼠标未移动时，程序会在这里阻塞，直到鼠标移动，提取出当前鼠标位置，继续往下运行if (PR.Status != PromptStatus.OK){return SamplerStatus.Cancel;}if (PR.Value.DistanceTo(((Line)Entity).EndPoint) < 0.000001f)//若当前鼠标位置离上一次绘制的位置很近，返回NoChange，不让系统去调用Update去刷新//此举是为了减少刷新频率，避免绘制时的闪烁//（需要注意的是Jig绘制刚开始和结束的瞬间， 即便Sampler返回的是NoChange，也会调用Update）return SamplerStatus.NoChange;m_AcquirePoint = PR.Value;//更新数据，返回OK,告诉系统，数据已整理好，需要刷新return SamplerStatus.OK;}protected override bool Update()//刷新（方法中应写对Base.Entity的更改,Sampler返回OK时调用）,(在开始绘制时即便Sampler返回NoChange也会调用,绘制的是圆时应避免给圆的半径赋值零,圆实体会退化成点){((Line)Entity).EndPoint = m_AcquirePoint;//利用绘制好的点去改变实体属性(EntityJig内部实现会把Entity成员绘制到模型空间)return true;}private Point3d m_AcquirePoint;//保存提取出来的鼠标位置}

DrawJig（多实体绘制）

//DrawJig没有了Entity成员，需要自己定义绘制的实体的成员变量class MyDoubleLineJig : DrawJig{public MyDoubleLineJig(Point3d _basePt){line_1 = new Line();line_2 = new Line();m_BasePt = _basePt;m_gap = 10.0f;}public static bool StartDraw(){Document doc = Application.DocumentManager.MdiActiveDocument;Point3d startPt = Point3d.Origin;PromptStatus promptStatus = GetPoint("\n输入起点", ref startPt);//需自己实现（获取用户的点输入）if (promptStatus != PromptStatus.OK)return false;MyDoubleLineJig lineJig = new MyDoubleLineJig(startPt);PromptResult PR = doc.Editor.Drag(lineJig);if (PR.Status != PromptStatus.OK)return false;AppendEntityToModalSpace(doc, lineJig.line_1);//需自己实现（将实体添加进模型空间）AppendEntityToModalSpace(doc, lineJig.line_2);return true;}protected override SamplerStatus Sampler(JigPrompts prompts){JigPromptPointOptions m_JPPO = new JigPromptPointOptions();m_JPPO.Message = "\ninput end point";m_JPPO.UserInputControls = (UserInputControls.Accept3dCoordinates | UserInputControls.NullResponseAccepted | UserInputControls.AnyBlankTerminatesInput);PromptPointResult PR = prompts.AcquirePoint(m_JPPO);if (PR.Status != PromptStatus.OK)return SamplerStatus.Cancel;Point3d pt = PR.Value;if (PR.Value == m_AcquirePt)return SamplerStatus.NoChange;m_AcquirePt = PR.Value;return SamplerStatus.OK;}//与Entity最大不同的在这里（Update->WorldDraw）protected override bool WorldDraw(WorldDraw draw){Vector3d lineV = m_AcquirePt - m_BasePt;Vector3d perpV = lineV.RotateBy(Math.PI / 2.0f, Vector3d.ZAxis);perpV = perpV.GetNormal() * m_gap;line_1.StartPoint = m_BasePt + perpV;line_2.StartPoint = m_BasePt - perpV;line_1.EndPoint = m_AcquirePt + perpV;line_2.EndPoint = m_AcquirePt - perpV;line_1.WorldDraw(draw);//需要调用WorldDraw将想要绘制的实体绘制到模型空间line_2.WorldDraw(draw);return true;}Line line_1;Line line_2;Point3d m_BasePt;Point3d m_AcquirePt;double m_gap;}