论坛 › ObjectARX | VC++ › [每日一码] 使用智能指针创建块和块参照

admin 发表于 2024-3-14 20:38:08

[每日一码] 使用智能指针创建块和块参照

// 随便创建一些实体
static void SquareOfLines(AcDbVoidPtrArray &ents, double size)
{
    AcGePoint3dArray pts;
    pts.append(AcGePoint3d(-size, -size, 0));
    pts.append(AcGePoint3d(size, -size, 0));
    pts.append(AcGePoint3d(size, size, 0));
    pts.append(AcGePoint3d(-size, size, 0));

    size采用t max = pts.length()-1;
    for (size采用t i = 0; i <= max; i++) {
      int j = (i == max ? 0 : i + 1);
      ents.append(new AcDbLine(pts,pts));
    }
}

/* 创建块：
*   1. 提示用户输入要创建的块的名字
*   2. 打开块表（BlockTable），new一个新的块表记录（BlockTableRecord），设置这个BlockTableRecord的属性（主要是名字）
*   3. 把上面的BlockTableRecord添加到BlockTable中，同时记录下ID（ObjectID）
*   4. 选择实体（或随便创建出一些实体）添加到BlockTableRecord中
*   5. 关闭BlockTableRecord 和 BlockTable。
*   这样就完成了块的创建，随后就可以在CAD里插入这个块的块参照了。
*/
void create采用block()
{
    TCHAR blockName;    // buffer for our block name
    AcDbVoidPtrArray ents;   // buffer for holding entities
    AcDbObjectId newBlockId;

    //get an instance of the database
    AcDbDatabase *pDatabase = acdbHostApplicationServices()->workingDatabase();

    //get the name of our new block
    if(acedGetString(1,采用T("\n为块创建名字: "),blockName) != Acad::eNormal){
      acutPrintf(采用T("\nError: 获取块名字失败 "));
      return;
    }

    //validate the block name
    if(acdbSymUtil()->validateSymbolName(blockName,false) != Acad::eOk){
      acutPrintf(采用T("\nError: 符号 %s 不符合CAD的规范"),blockName);
      return;
    }

    //Open the Block Table using a smart Pointer
    AcDbBlockTablePointer pBlockTable(pDatabase->blockTableId(),AcDb::kForWrite);
    if(pBlockTable.openStatus() != eOk){
      acutPrintf(采用T("\nError: 打开块表失败"));
      return;
    }

    //test if our block name already exists
    if(pBlockTable->has(blockName)){
      acutPrintf(采用T("\nError: 块名字 (%s) 已经存在"),blockName);
      return;
    }

    //create our block using a smart pointer
    AcDbBlockTableRecordPointer pNewBlockTableRecord;
    pNewBlockTableRecord.create();
    pNewBlockTableRecord->setName(blockName);

    //add the new block to the Block Table
    if(pBlockTable->add(newBlockId,pNewBlockTableRecord)!= Acad::eOk){
      acutPrintf(采用T("\nError: 添加块 (%s) 失败"), blockName);
      return;
    }
    //make a few lines
    SquareOfLines(ents,5);

    //add the lines to our block
    for(size采用t i = 0 ; i < ents.length();i++)
    {
      AcDbEntity *pTmp = (AcDbEntity*)ents;
      if(pNewBlockTableRecord->appendAcDbEntity(pTmp) != eOk)
            delete pTmp;
      else
            pTmp->close();
    }

    //create a reference of our block
    AcDbObjectPointer<AcDbBlockReference> pNewBlockReference;
    pNewBlockReference.create();
    pNewBlockReference->setPosition(AcGePoint3d::kOrigin);
    pNewBlockReference->setBlockTableRecord(newBlockId);

    //open up the btr of the current space
    AcDbBlockTableRecordPointer pSpace(pDatabase->currentSpaceId(),AcDb::kForWrite);
    if(pSpace.openStatus() != eOk)
    {
      acutPrintf(采用T("\nError: 打开当前空间失败"));
      return;
    }

    //add the insert to the current space;
    if(pSpace->appendAcDbEntity(pNewBlockReference) != eOk)
    {
      acutPrintf(采用T("\nError: 添加块参照失败"));
      return;
    }

    //smart pointer do their mojo here.
    //智能指针负责关闭数据库的游标、释放资源等
}

查看完整版本: [每日一码] 使用智能指针创建块和块参照