[每日一码] 使用智能指针创建块和块参照

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1. // 随便创建一些实体
2. static void SquareOfLines(AcDbVoidPtrArray &ents, double size)
3. {
4.     AcGePoint3dArray pts;
5.     pts.append(AcGePoint3d(-size, -size, 0));
6.     pts.append(AcGePoint3d(size, -size, 0));
7.     pts.append(AcGePoint3d(size, size, 0));
8.     pts.append(AcGePoint3d(-size, size, 0));
10.     size采用t max = pts.length()-1;
11.     for (size采用t i = 0; i <= max; i++) {
12.         int j = (i == max ? 0 : i + 1);
13.         ents.append(new AcDbLine(pts[i],pts[j]));
14.     }
15. }
17. /* 创建块：
18. *   1. 提示用户输入要创建的块的名字
19. *   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）
20. *   3. 把上面的BlockTableRecord添加到BlockTable中，同时记录下ID（ObjectID）
21. *   4. 选择实体（或随便创建出一些实体）添加到BlockTableRecord中
22. *   5. 关闭BlockTableRecord 和 BlockTable。
23. *   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。
24. */
25. void create采用block()
26. {
27.     TCHAR blockName[133];    // buffer for our block name
28.     AcDbVoidPtrArray ents;   // buffer for holding entities
29.     AcDbObjectId newBlockId;
31.     //get an instance of the database
32.     AcDbDatabase *pDatabase = acdbHostApplicationServices()->workingDatabase();
34.     //get the name of our new block
35.     if(acedGetString(1,采用T("\n为块创建名字: "),blockName) != Acad::eNormal){
36.         acutPrintf(采用T("\nError: 获取块名字失败 "));
37.         return;
38.     }
40.     //validate the block name
41.     if(acdbSymUtil()->validateSymbolName(blockName,false) != Acad::eOk){
42.         acutPrintf(采用T("\nError: 符号 %s 不符合CAD的规范"),blockName);
43.         return;
44.     }
46.     //Open the Block Table using a smart Pointer
47.     AcDbBlockTablePointer pBlockTable(pDatabase->blockTableId(),AcDb::kForWrite);
48.     if(pBlockTable.openStatus() != eOk){
49.         acutPrintf(采用T("\nError: 打开块表失败"));
50.         return;
51.     }
53.     //test if our block name already exists
54.     if(pBlockTable->has(blockName)){
55.         acutPrintf(采用T("\nError: 块名字 (%s) 已经存在"),blockName);
56.         return;
57.     }
59.     //create our block using a smart pointer
60.     AcDbBlockTableRecordPointer pNewBlockTableRecord;
61.     pNewBlockTableRecord.create();
62.     pNewBlockTableRecord->setName(blockName);
64.     //add the new block to the Block Table
65.     if(pBlockTable->add(newBlockId,pNewBlockTableRecord)!= Acad::eOk){
66.         acutPrintf(采用T("\nError: 添加块 (%s) 失败"), blockName);
67.         return;
68.     }
69.     //make a few lines
70.     SquareOfLines(ents,5);
72.     //add the lines to our block
73.     for(size采用t i = 0 ; i < ents.length();i++)
74.     {
75.         AcDbEntity *pTmp = (AcDbEntity*)ents[i];
76.         if(pNewBlockTableRecord->appendAcDbEntity(pTmp) != eOk)
77.             delete pTmp;
78.         else
79.             pTmp->close();
80.     }
82.     //create a reference of our block
83.     AcDbObjectPointer<AcDbBlockReference> pNewBlockReference;
84.     pNewBlockReference.create();
85.     pNewBlockReference->setPosition(AcGePoint3d::kOrigin);
86.     pNewBlockReference->setBlockTableRecord(newBlockId);
88.     //open up the btr of the current space
89.     AcDbBlockTableRecordPointer pSpace(pDatabase->currentSpaceId(),AcDb::kForWrite);
90.     if(pSpace.openStatus() != eOk)
91.     {
92.         acutPrintf(采用T("\nError: 打开当前空间失败"));
93.         return;
94.     }
96.     //add the insert to the current space;
97.     if(pSpace->appendAcDbEntity(pNewBlockReference) != eOk)
98.     {
99.         acutPrintf(采用T("\nError: 添加块参照失败"));
100.         return;
101.     }
103.     //smart pointer do their mojo here.
104.     //智能指针负责关闭数据库的游标、释放资源等
105. }

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