简单模拟多段线绘制Pline命令过程的撤销功能

简单模拟多段线绘制Pline命令过程的撤销功能

这是关于多段线pline命令中的撤销功能的简单代码

代码使用了事务管理器来执行增加对象和撤销处理.

代码

		/// <summary>
		/// 简单模拟多段线绘制过程的撤销功能.
		/// code by edata 2020-3-11 
		/// </summary>
		/// <remarks>简单模拟多段线绘制过程的_u撤销功能.仅考虑了UCS问题</remarks>
		//设置坐标系转换缓冲区链表
		resbuf ucs,wcs;
		ucs.restype=RTSHORT;
		ucs.resval.rint=1;
		wcs.restype=RTSHORT;
		wcs.resval.rint=0;

		ads_point pt;
		ads_point ptWcs;
		if (RTNORM != acedGetPoint(NULL,_T("
 选择起点: "),pt))
		{
			return;
		}
		acedTrans(pt,&ucs,&wcs,0,ptWcs);
		AcGePoint3d p1=asPnt3d(ptWcs);
		AcGePoint3d ptStart=p1;
		AcDbPolyline *pPoly=NULL;
		//开启事务管理器
		AcTransaction *pTrans =actrTransactionManager->startTransaction();
		while (true)
		{
			CString strPrompt=_T("
 选择下一个点[(U)撤销]: ");
			CString strKword=_T("Undo _ u");
			if (pPoly!=NULL)
			{
				int nCount =pPoly->numVerts();
				if (nCount>1)
				{
					strPrompt=_T("
 选择下一个点[(U)撤销/(C)闭合]: ");
					strKword=_T("Undo Close _ u c");	
										
				}
			}
			
			//设置使用Undo关键字,该值允许使用ctrl+z撤销
			acedInitGet(NULL,strKword);
			int nRet=acedGetPoint(pt,strPrompt,pt);
			if (RTKWORD == nRet)
			{
				ACHAR szKword[132];
				if (RTNORM != acedGetInput(szKword))
				{
					continue;
				}
				if (_tcscmp(szKword,_T("u")) == 0)
				{
					if (pPoly != NULL)
					{
						int nCount = pPoly->numVerts();
						if (nCount>0)
						{
							//此处使用removeVertexAt不能移除仅剩的一个点,后面对1个点的线取消事务
							Acad::ErrorStatus es= pPoly->removeVertexAt(nCount-1);	
							//重新生成
							pPoly->draw();
							if (nCount>1)
							{
								pPoly->getEndPoint(p1);
								pt[X] = p1.x;
								pt[Y] = p1.y;
								pt[Z] = p1.z;
								acedTrans(pt,&wcs,&ucs,0,pt);
							}
							else
							{							
								p1=ptStart;
								pt[X] = p1.x;
								pt[Y] = p1.y;
								pt[Z] = p1.z;
								acedTrans(pt,&wcs,&ucs,0,pt);
							}
						}					
					}
				}
				else if (_tcscmp(szKword,_T("c")) == 0)
				{
					if (pPoly!=NULL)
					{
						int nCount =pPoly->numVerts();
						if (nCount>1)
						{
							pPoly->setClosed(true);
							break;
						}
					}
				}				
				continue;
			}
			else if (RTNORM != nRet)
			{
				break;
			}

			acedTrans(pt,&ucs,&wcs,0,ptWcs);
			AcGePoint3d p2=asPnt3d(ptWcs);			
			//处理多段线图形
			if (pPoly == NULL)
			{
				pPoly = new AcDbPolyline();
				pPoly->addVertexAt(0,AcGePoint2d(p1.x,p1.y));
				pPoly->addVertexAt(1,AcGePoint2d(p2.x,p2.y));
				//添加到当前数据库当前空间
				AddEntToCurSpace(pPoly);
				//添加对象到事务处理
				actrTransactionManager->addNewlyCreatedDBRObject(pPoly);
				//显示图形
				pPoly->draw();
			}
			else
			{
				int nCount = pPoly->numVerts();
				pPoly->addVertexAt(nCount,AcGePoint2d(p2.x,p2.y));
				//显示图形
				pPoly->draw();
			}		
			p1=p2;
		}

		if (pPoly == NULL)
		{
			//未创建多段线,终止事务
			actrTransactionManager->abortTransaction();
			return;
		}
		else
		{
			int nCount = pPoly->numVerts();
			if (nCount == 1)
			{
				//仅有一个点,终止事务
				actrTransactionManager->abortTransaction();
				return;
			}
		}
		//事务结束
		actrTransactionManager->endTransaction();

AddEntToCurSpace 添加实体对象到当前数据库当前空间

代码

	static Acad::ErrorStatus AddEntToCurSpace(AcDbEntity *pEnt)
	{
		AcDbObjectId objId=AcDbObjectId::kNull;
		return AddEntToCurSpace(pEnt,objId);
	}
	static Acad::ErrorStatus AddEntToCurSpace(AcDbEntity *pEnt,AcDbObjectId &objId)
	{
		if (pEnt == NULL)
		{
			return Acad::eNullEntityPointer;
		}
		AcDbBlockTableRecordPointer pBlkRcd(acdbHostApplicationServices()->workingDatabase()->currentSpaceId(),AcDb::kForWrite);
		if (Acad::eOk != pBlkRcd.openStatus())
		{
			return pBlkRcd.openStatus(); 
		}
		return pBlkRcd->appendAcDbEntity(objId,pEnt);
	}

结束语:使用事务管理器的时候,事务中的对象不能使用close()关闭对象了;