AcDbHatch associativity

newer

AcDbHatch associativity

问题：

After I made a hatch object, added it to the database, set the style, and so on, it is not associative to the object. What must I do to make it associative?

解答：
Use the hatch object that was just created as a persistent reactor for the entities to which it is hatching. The following sample demonstrates how to create a hatch and associate it to the boundary entities (a rectangle and a circle).

1. static Acad::ErrorStatus postToDb(AcDbEntity* ent, AcDbObjectId& objId)
   
2. {
   
3. Acad::ErrorStatus es;
   
4. AcDbBlockTable* pBlockTable;
   
5. AcDbBlockTableRecord* pSpaceRecord;
   
6. if (ent==NULL)
   
7.   return Acad::eNullObjectPointer;
   
8. if (acdbHostApplicationServices()->workingDatabase()==NULL)
   
9.   return Acad::eNoDatabase;
   
10. if ((es = acdbHostApplicationServices()->workingDatabase()->getBlockTable(pBlockTable, AcDb::kForRead))!=Acad::eOk)
    
11.   return es;
    
12. if ((es =pBlockTable->getAt(ACDB_MODEL_SPACE,pSpaceRecord,AcDb::kForWrite)) != Acad::eOk)
    
13. {
    
14.   pBlockTable->close();
    
15.   return es;
    
16. }
    
17. pBlockTable->close();
    
18. if ((es = pSpaceRecord->appendAcDbEntity(objId, ent)) != Acad::eOk)
    
19. { pSpaceRecord->close();
    
20. return es;
    
21. }
    
22. pSpaceRecord->close();
    
23. return ent->close();
    
24. }
    
25. 
    
26. 
    
27. static void Test()
    
28. {
    
29. AcDbHatch* pHatch = new AcDbHatch();
    
30. // Set hatch plane
    
31. AcGeVector3d normal(0.0, 0.0, 1.0);
    
32. pHatch->setNormal(normal);
    
33. pHatch->setElevation(0.0);
    
34. // Set hatch pattern to ANSI31 predefined type //
    
35. pHatch->setPattern(AcDbHatch::kPreDefined, _T("ANSI31"));
    
36. // Set Associativity
    
37. pHatch->setAssociative(Adesk::kTrue);
    
38. // Construct database AcDbLines
    
39. AcGePoint3d vertexPts[4];
    
40. AcDbObjectId lineId, cirId, hatchId;
    
41. AcDbObjectIdArray dbObjIds;
    
42. AcDbLine *line;
    
43. vertexPts[0].set(2.0, 2.0, 0.0);
    
44. vertexPts[1].set(8.0, 2.0, 0.0);
    
45. vertexPts[2].set(8.0, 8.0, 0.0);
    
46. vertexPts[3].set(2.0, 8.0, 0.0);
    
47. for (int i = 0; i < 4; i++)
    
48. {
    
49.   line = new AcDbLine();
    
50.   line->setStartPoint(vertexPts);
    
51.   line->setEndPoint(vertexPts[(i == 3) ? 0 : i+1]);
    
52.   postToDb(line, lineId);
    
53.   dbObjIds.append(lineId);
    
54. }
    
55. // Append an external rectangular loop to hatch boundary //
    
56. pHatch->appendLoop(AcDbHatch::kExternal, dbObjIds);
    
57. // Create a AcDbCircle and post it to database //
    
58. AcGePoint3d cenPt(5.0, 5.0, 0.0);
    
59. normal.set(0.0, 0.0, 1.0);
    
60. AcDbCircle *circle = new AcDbCircle();
    
61. circle->setNormal(normal);
    
62. circle->setCenter(cenPt);
    
63. circle->setRadius(1.0);
    
64. postToDb(circle, cirId);
    
65. dbObjIds.setLogicalLength(0);
    
66. dbObjIds.append(cirId);
    
67. // Append an internal loop (circle) to hatch boundary //
    
68. pHatch->appendLoop(AcDbHatch::kDefault, dbObjIds);
    
69. // Elaborate hatch lines
    
70. pHatch->evaluateHatch();
    
71. // Get all associative source boundary object Ids for later use. //
    
72. dbObjIds.setLogicalLength(0);
    
73. pHatch->getAssocObjIds(dbObjIds);
    
74. // Post hatch entity to database
    
75. postToDb(pHatch, hatchId);
    
76. // Attach hatchId to all source boundary objects for notification. //
    
77. AcDbEntity *pEnt;
    
78. int numObjs = dbObjIds.length();
    
79. for (int i = 0; i < numObjs; i++)
    
80. {
    
81.   if (acdbOpenAcDbEntity(pEnt, dbObjIds,AcDb::kForWrite)==Acad::eOk)
    
82.   {
    
83.    pEnt->addPersistentReactor(hatchId);
    
84.    pEnt->close();
    
85.   }
    
86. }
    
87. }

static Acad::ErrorStatus postToDb(AcDbEntity* ent, AcDbObjectId& objId)<br /> {<br /> Acad::ErrorStatus es;<br /> AcDbBlockTable* pBlockTable;<br /> AcDbBlockTableRecord* pSpaceRecord;<br /> if (ent==NULL)<br />   return Acad::eNullObjectPointer;<br /> if (acdbHostApplicationServices()->workingDatabase()==NULL)<br />   return Acad::eNoDatabase;<br /> if ((es = acdbHostApplicationServices()->workingDatabase()->getBlockTable(pBlockTable, AcDb::kForRead))!=Acad::eOk)<br />   return es;<br /> if ((es =pBlockTable->getAt(ACDB_MODEL_SPACE,pSpaceRecord,AcDb::kForWrite)) != Acad::eOk)<br /> {<br />   pBlockTable->close();<br />   return es;<br /> }<br /> pBlockTable->close();<br /> if ((es = pSpaceRecord->appendAcDbEntity(objId, ent)) != Acad::eOk)<br /> { pSpaceRecord->close();<br /> return es;<br /> }<br /> pSpaceRecord->close();<br /> return ent->close();<br /> }<br /> <br /> <br /> static void Test()<br /> {<br /> AcDbHatch* pHatch = new AcDbHatch();<br /> // Set hatch plane<br /> AcGeVector3d normal(0.0, 0.0, 1.0);<br /> pHatch->setNormal(normal);<br /> pHatch->setElevation(0.0);<br /> // Set hatch pattern to ANSI31 predefined type //<br /> pHatch->setPattern(AcDbHatch::kPreDefined, _T("ANSI31"));<br /> // Set Associativity<br /> pHatch->setAssociative(Adesk::kTrue);<br /> // Construct database AcDbLines<br /> AcGePoint3d vertexPts[4];<br /> AcDbObjectId lineId, cirId, hatchId;<br /> AcDbObjectIdArray dbObjIds;<br /> AcDbLine *line;<br /> vertexPts[0].set(2.0, 2.0, 0.0);<br /> vertexPts[1].set(8.0, 2.0, 0.0);<br /> vertexPts[2].set(8.0, 8.0, 0.0);<br /> vertexPts[3].set(2.0, 8.0, 0.0);<br /> for (int i = 0; i < 4; i++)<br /> {<br />   line = new AcDbLine();<br />   line->setStartPoint(vertexPts<i>);<br />   line->setEndPoint(vertexPts[(i == 3) ? 0 : i+1]);<br />   postToDb(line, lineId);<br />   dbObjIds.append(lineId);<br /> }<br /> // Append an external rectangular loop to hatch boundary //<br /> pHatch->appendLoop(AcDbHatch::kExternal, dbObjIds);<br /> // Create a AcDbCircle and post it to database //<br /> AcGePoint3d cenPt(5.0, 5.0, 0.0);<br /> normal.set(0.0, 0.0, 1.0);<br /> AcDbCircle *circle = new AcDbCircle();<br /> circle->setNormal(normal);<br /> circle->setCenter(cenPt);<br /> circle->setRadius(1.0);<br /> postToDb(circle, cirId);<br /> dbObjIds.setLogicalLength(0);<br /> dbObjIds.append(cirId);<br /> // Append an internal loop (circle) to hatch boundary //<br /> pHatch->appendLoop(AcDbHatch::kDefault, dbObjIds);<br /> // Elaborate hatch lines<br /> pHatch->evaluateHatch();<br /> // Get all associative source boundary object Ids for later use. //<br /> dbObjIds.setLogicalLength(0);<br /> pHatch->getAssocObjIds(dbObjIds);<br /> // Post hatch entity to database<br /> postToDb(pHatch, hatchId);<br /> // Attach hatchId to all source boundary objects for notification. //<br /> AcDbEntity *pEnt;<br /> int numObjs = dbObjIds.length();<br /> for (int i = 0; i < numObjs; i++)<br /> {<br />   if (acdbOpenAcDbEntity(pEnt, dbObjIds<i>,AcDb::kForWrite)==Acad::eOk)<br />   {<br />    pEnt->addPersistentReactor(hatchId);<br />    pEnt->close();<br />   }<br /> }<br /> }