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实现夹点函数

2024-5-18 19:24| 发布者: admin| 查看: 307| 评论: 0|原作者: admin|来自: AutoCAD

实现夹点函数

AutoCAD 图元具有当用户选择带有指针设备的图元时显示的夹点。该函数返回已为实体定义的夹点。该函数执行由夹点编辑导致的实体修改。getGripPoints()moveGripPointsAt()

使用夹点编辑中的拉伸模式，您可以通过将选定的夹点移动到新位置来拉伸对象。AutoCAD 在用户处于拉伸模式时调用该函数。但是，对于某些实体，某些夹点会移动对象而不是拉伸对象。这些夹点包括对文本对象、块、线条中点、圆心、椭圆中心和点对象的夹点。在这些情况下，该函数调用 .moveGripPointsAt()moveGripPointsAt()transformBy()

注意：该函数的默认实现是调用该函数。AcDbEntity::moveGripPointsAt()transformBy()

当用户处于抓取、移动、旋转、缩放或镜像模式时，AutoCAD 将调用“图元”部分中所述的函数。transformBy()

如果希望用户能够使用夹点编辑实体，则需要重写 and 函数。该实体定义其夹持点以及如何解释用户提供的偏移量。subGetGripPoints()subMoveGripPointsAt()

下面的摘录演示自定义类如何实现这些函数。此类定义的对象在每个顶点处都有一个夹持点，在其中心有一个夹点。这些抓取点由函数返回。如果用户在夹持拉伸模式下选择夹持点，AutoCAD 将调用该函数。这将调用自定义实体的，传入所选抓取点的索引数组和一个 3D 矢量，指定用户移动指点设备的程度。如果用户选择了顶点夹点，则多边形将按指定的偏移量均匀拉伸。如果用户选取了中心夹点，则多边形将简单地平移等于偏移量。（此值将传递给函数，如下所示。AsdkPolysubGetGripPoints()moveGripPointsAt()subMoveGripPointsAt()transformBy()

Acad::ErrorStatus 
 AsdkPoly::subGetGripPoints( 
     AcGePoint3dArray& gripPoints, 
     AcDbIntArray& osnapModes, 
     AcDbIntArray& geomIds) const 
 { 
     assertReadEnabled(); 
     Acad::ErrorStatus es; 
     if ((es = getVertices3d(gripPoints)) != Acad::eOk) { 
         return es; 
     } 
  
     // Remove the duplicate point at the start/end and add 
     // center as the last point. 
     // 
     gripPoints.removeAt(gripPoints.length() - 1); 
     AcGePoint3d center; 
     getCenter(center); 
     gripPoints.append(center); 
     return es; 
 }

Acad::ErrorStatus 
 AsdkPoly::subMoveGripPointsAt( 
     const AcDbIntArray& indices, 
     const AcGeVector3d& offset) 
 { 
     if (indices.length()== 0 || offset.isZeroLength()) 
         return Acad::eOk; //that's easy :-) 
  
     if (mDragDataFlags & kCloneMeForDraggingCalled) { 
         mDragDataFlags |= kUseDragCache; 
     } else 
         // Only if we're not dragging do we want to make an undo 
         // recording and check if the object's open for write. 
         // 
         assertWriteEnabled(); 
  
     //if there more than one hot vertex or there's one and it 
     // is the center then simply transform 
     if (indices.length()>1 || indices[0] == mNumSides) 
         return transformBy(AcGeMatrix3d::translation(offset)); 
          
     AcGeVector3d off(offset); 
     //calculate the offset vector of the startpoint 
     //from the offset vector on a vertex 
     double rotateBy = 2.0 * 3.14159265358979323846 / 
       nNumSides * indices[0]; 
     AcGePoint3d cent; 
     getCenter(cent); 
     off.transformBy(AcGeMatrix3d::rotation(-rotateBy,
      normal(),cent)); 
     acdbWcs2Ecs(asDblArray(off),asDblArray(off),asDblArray(normal()),
  Adesk::kTrue); 
     if (mDragDataFlags & kUseDragCache){ 
         mDragCenter = mCenter; 
         mDragPlaneNormal = mPlaneNormal; 
         mDragStartPoint = mStartPoint + AcGeVector2d(off.x,off.y); 
         mDragElevation = mElevation + off.z; 
     }else{ 
         mStartPoint = mStartPoint + AcGeVector2d(off.x,off.y); 
         mElevation = mElevation + off.z; 
     } 
     return Acad::eOk; 
 }