Kean专题：内容JIG（拖拽）

一、使用Jig动态旋转实体（转载：明经通道 mccad 翻译）

原文转载自：http://through-the-interface.typepad.com/through_the_interface/jigs/（该口已无法访问）

可访问转载入口：http://bbs.mjtd.com/thread-75618-1-1.html（转载自明镜通道by雪山飞狐_lzh）

原kean博客已经无法看到，故转载明经通道雪山飞狐_lzh老师整理内容

1.keen源码内容翻译及源码展示：
2008年3月28日
通过 .NET 动态旋转AutoCAD 图元
本文由明经通道 mccad 翻译，转载请注明出处
在上一文章中有一有趣的需求与另一文章中的问题相似。原来的问题是以矩形的中心旋转矩形多段线图元，并且之后还可继续旋转它。有几点我比较感兴趣：
矩形是由四个点组成的简单多段线，它并不存在中心点和旋转角度的概念。
至少对我来说，很明显需要计算中心点并将旋转角度做为XData保存在多段线上。
要形象化的修改最好是以动态方式。
大部分示例是演示如何使用动态来创建新图元，而非修改现有图元。
因此，考虑到这一点，我使用以下C#代码来解决这个问题：

keen源码：

using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.Geometry;
namespace RotatingRectangles
{
public class Commands
{
// Define some constants we'll use to
// store our XData 定义一些常量，我们用来储存扩展数据
// AppName is our RDS (TTIF, for
// "Through The InterFace") plus an indicator
// what it's for (ROTation) 在解释那个TTIF_ROT RDS 远程数据服务？
const string kRegAppName = "TTIF_ROT";
const int kAppCode = 1001;
const int kRotCode = 1040;
class RotateJig : EntityJig
{
// Declare some internal state 声明一些内容状态
double m_baseAngle, m_deltaAngle;
Point3d m_rotationPoint;
Matrix3d m_ucs;
// Constructor sets the state and clone the entity passed in (adequate for simple entities)
构造器设置状态并且复制传入的实体
public RotateJig(
Entity ent,
Point3d rotationPoint,
double baseAngle,
Matrix3d ucs)
: base(ent.Clone() as Entity)
{
m_rotationPoint = rotationPoint;
m_baseAngle = baseAngle;
m_ucs = ucs;
}
protected override SamplerStatus Sampler(
JigPrompts jp
)
{
// We acquire a single angular value
JigPromptAngleOptions jo =
new JigPromptAngleOptions(
" Angle of rotation: "
);
jo.BasePoint = m_rotationPoint;
jo.UseBasePoint = true;
PromptDoubleResult pdr =
jp.AcquireAngle(jo);
if (pdr.Status == PromptStatus.OK)
{
// Check if it has changed or not (reduces flicker)
if (m_deltaAngle == pdr.Value)
{
return SamplerStatus.NoChange;
}
else
{
// Set the change in angle to the new value
m_deltaAngle = pdr.Value;
return SamplerStatus.OK;
}
}
return SamplerStatus.Cancel;
}
protected override bool Update()
{
// We rotate the polyline by the change minus the base angle
Matrix3d trans =
Matrix3d.Rotation(
m_deltaAngle - m_baseAngle,
m_ucs.CoordinateSystem3d.Zaxis,
m_rotationPoint);
Entity.TransformBy(trans);
// The base becomes the previous delta and the delta gets set to zero
m_baseAngle = m_deltaAngle;
m_deltaAngle = 0.0;
return true;
}
public Entity GetEntity()
{
return Entity;
}
public double GetRotation()
{
// The overall rotation is the base plus the delta
return m_baseAngle + m_deltaAngle;
}
}
[CommandMethod("ROT")]
public void RotateEntity()
{
Document doc =
Application.DocumentManager.MdiActiveDocument;
Editor ed = doc.Editor;
Database db = doc.Database;
// First we prompt for the entity to rotate
PromptEntityOptions peo =
new PromptEntityOptions(
" Select entity to rotate: "
);
PromptEntityResult per =
ed.GetEntity(peo);
if (per.Status == PromptStatus.OK)
{
Transaction tr =
db.TransactionManager.StartTransaction();
using (tr)
{
DBObject obj =
tr.GetObject(per.ObjectId, OpenMode.ForRead);
Entity ent = obj as Entity;
// Use the origin as the default center
Point3d rotationPoint = Point3d.Origin;
// If the entity is a polyline,assume it is rectangular and then set the rotation point as its center
Polyline pl = obj as Polyline;
if (pl != null)
{
LineSegment3d ps0 =
pl.GetLineSegmentAt(0);
LineSegment3d ps1 =
pl.GetLineSegmentAt(1);
Vector3d vec =
((ps0.EndPoint - ps0.StartPoint) / 2.0) +
((ps1.EndPoint - ps1.StartPoint) / 2.0);
rotationPoint = pl.StartPoint + vec;
}
// Get the base rotation angle stored with the
// entity, if there was one (default is 0.0)
double baseAngle = GetStoredRotation(obj);
if (ent != null)
{
// Get the current UCS, to pass to the Jig
Matrix3d ucs =
ed.CurrentUserCoordinateSystem;
// Create our jig object
RotateJig jig =
new RotateJig(
ent,
rotationPoint,
baseAngle,
ucs
);
PromptResult res = ed.Drag(jig);
if (res.Status == PromptStatus.OK)
{
// Get the overall rotation angle
// and dispose of the temp clone
double newAngle = jig.GetRotation();
jig.GetEntity().Dispose();
// Rotate the original entity
Matrix3d trans =
Matrix3d.Rotation(
newAngle - baseAngle,
ucs.CoordinateSystem3d.Zaxis,
rotationPoint);
ent.UpgradeOpen();
ent.TransformBy(trans);
// Store the new rotation as XData
SetStoredRotation(ent, newAngle);
}
}
tr.Commit();
}
}
}
// Helper function to create a RegApp
static void AddRegAppTableRecord(string regAppName)
{
Document doc =
Application.DocumentManager.MdiActiveDocument;
Editor ed = doc.Editor;
Database db = doc.Database;
Transaction tr =
doc.TransactionManager.StartTransaction();
using (tr)
{
RegAppTable rat =
(RegAppTable)tr.GetObject(
db.RegAppTableId,
OpenMode.ForRead,
false
);
if (!rat.Has(regAppName))
{
rat.UpgradeOpen();
RegAppTableRecord ratr =
new RegAppTableRecord();
ratr.Name = regAppName;
rat.Add(ratr);
tr.AddNewlyCreatedDBObject(ratr, true);
}
tr.Commit();
}
}
// Store our rotation angle as XData
private void SetStoredRotation(
DBObject obj, double rotation)
{
AddRegAppTableRecord(kRegAppName);
ResultBuffer rb = obj.XData;
if (rb == null)
{
rb =
new ResultBuffer(
new TypedValue(kAppCode, kRegAppName),
new TypedValue(kRotCode, rotation)
);
}
else
{
// We can simply add our values - no need
// to remove the previous ones, the new ones
// are the ones that get stored
rb.Add(new TypedValue(kAppCode, kRegAppName));
rb.Add(new TypedValue(kRotCode, rotation));
}
obj.XData = rb;
rb.Dispose();
}
// Retrieve the existing rotation angle from XData
private double GetStoredRotation(DBObject obj)
{
double ret = 0.0;
ResultBuffer rb = obj.XData;
if (rb != null)
{
// If we find our group code, it means that on
// the next iteration, we'll get our rotation
bool bReadyForRot = false;
foreach (TypedValue tv in rb)
{
if (bReadyForRot)
{
if (tv.TypeCode == kRotCode)
ret = (double)tv.Value;
bReadyForRot = false;
}
if (tv.TypeCode == kAppCode)
bReadyForRot = true;
}
rb.Dispose();
}
return ret;
}
}
}

试用代码前，可用 RECTANG 命令创建一水平方向矩形，然后使用自定义的ROT命令来旋转它
之后再调用 ROT命令运行也会正常，因为图元“记住”了旋转角度。如果用了其它的工具旋转了这个矩形，这种效果就会消失。一种方法是深层的分析矩形来测量“旋转角度”：确定矩形的长边，获得它的角度。另一种毫无意义的方法是执行命令让用户输入角度(选择两个点或直接输入)。

2.keen源码的图形展示：

第一篇已有明经通道mccad 翻译，此部分内容直接转载了，接下来的日子里我争取在每周末对翻译的Kean的博客进行更新，也同时上传一些自己开发过程中实现的图形的以及图形的实现思路