AutoCAD DevBlog

Quick Tip: Can you use ADS functions with in-memory side databases

By Gopinath Taget

Consider this:

Using AcDbDatabase::readDwgFile(), you read several drawings into memory. With ads_entget() you try to get a resbuf of some DXF-values. But for most databases it returns NULL, while returning the correct value for some random databases. If ads-functions can be used on in-memory drawings, how do you direct the function to the correct drawing?

The short answer is, you cannot.

Some ADS functions might work with objects in other databases in some circumstances, but that is not by design. Therefore, you should not rely on of ADS style functions in such a case.

If you want to work on objects in databases that are not loaded into the AutoCAD editor, then you cannot safely use the ADS functions; you'll need to usenon-ads functions such as the methods in the various AcDb classes.

Create Bitmap Of Selected Entities

By Gopinath Taget

If you want to generate/create a BMP out of selected entities then you need to use Export() method of the AcadDocument class of ActiveX Automation API of AutoCAD.

The VC++ sample below creates a BMP image out of the selection set.

// Important: check ?Use MFC? option while creating the

// ObjectARX project using ObjectARX Wizard

 

void fCreateBMP()

{

 try

{

  IAcadApplicationPtr pApp;

  IAcadDocumentPtr pAtvDoc;

  IAcadSelectionSetPtr pSS;

  pApp = acedGetAcadWinApp()->GetIDispatch(TRUE);

 

  //get the active document and selectionset

  pApp->get_ActiveDocument(&pAtvDoc);

  pSS = pAtvDoc->get_ActiveSelectionSet(&pSS);

  pSS->SelectOnScreen();//without any filters

  if(S_OK == pAtvDoc->Export(_bstr_t("c:\\test"),

   _bstr_t("BMP"),pSS))

   acutPrintf(L"\nCreated BMP successfully.");

}

 catch (_com_error &es)

{

  acutPrintf(L"\nerror %s",(char *) es.Description());

}

}

Note that the bitmap is generated out of the viewable area of the current document and the size is dependent on the window size of the document while generating the bitmap.

If you want to control the size of the bitmap then before generating the bitmap, set the window size of the document using the Height() and Width() properties of IAcadDocument class. Also before changing the window size make sure that the windowState() is set to normal size. Then, zoom to the area that contains your objects, this you may have to do it programmatically after the user selects the objects on the screen.

How to get all the raster image references from the image definition object?

By Gopinath Taget

If the raster images were correctly created, then each AcDbRasterImage object has an AcDbRasterImageDefReactor attached to it.

A particular AcDbRasterImageDef object will contain soft pointer references to these reactors, so if you create a custom filer class, deriving from AcDbDwgFiler, you can easily retrieve the sofPointers Id of the reactor when calling "dwgOut()" on your image definition. Once you have collected the reactors, open the "owner" object, which is one of the RasterImages referencing this definition.

Below is the relevant code. Here is the the full project.

void GetRasterImageReferences(const ACHAR* strRasterImgName)

{

Acad::ErrorStatus es;

 

AcDbObjectId dicoId;

 

 if((dicoId = AcDbRasterImageDef::imageDictionary(acdbCurDwg()))

  == AcDbObjectId::kNull)

{

  acutPrintf(L"\nImage dictionary does not exist...");

  return;

}

 

AcDbDictionary* pDict;

 if((es = acdbOpenObject((AcDbObject*&)pDict,

  dicoId, AcDb::kForRead)) != Acad::eOk)

{

  acutPrintf(L"\nCould not open image dictionary...");

  return;

}

 

 

AcDbRasterImageDef* pImageDef;

 

 if (!pDict->has(strRasterImgName))

{

  acutPrintf(L"\nImage dictionary does not \

     contain specified definition...");

  return;

}

 

es = pDict->getAt(strRasterImgName,

  (AcDbObject*&)pImageDef, AcDb::kForRead);

pDict->close();

 

AcDbObjectIdArray hardPointerIds;

AcDbObjectIdArray softPointerIds;

AcDbObjectIdArray hardOwnershipIds;

AcDbObjectIdArray softOwnershipIds;

 

 

    asdkReferencesFiler filer;

 

pImageDef->dwgOut(&filer);

    pImageDef->close();

 

    hardPointerIds   = filer.m_hardPointerIds;

    softPointerIds   = filer.m_softPointerIds;

    hardOwnershipIds = filer.m_hardOwnershipIds;

    softOwnershipIds = filer.m_softOwnershipIds;

 

 

 for (int i = 0; i < softPointerIds.length(); i++)

{

  AcDbObject* pReference;

  if((es = acdbOpenObject((AcDbObject*&)pReference,

   softPointerIds[i], AcDb::kForRead)) != Acad::eOk)

  {

   acutPrintf(L"\nCould not open object");

   continue;

  }

 

  //acutPrintf(L"\nReference type: %s", pReference->isA()->name());

 

  AcDbRasterImageDefReactor* pImgReactor = NULL;

 

  if ((pImgReactor =

   AcDbRasterImageDefReactor::cast(pReference)) != NULL )

  {

   AcDbRasterImage* pImgReference;

   if((es = acdbOpenObject((AcDbObject*&)pImgReference,

    pImgReactor->ownerId(), AcDb::kForRead)) != Acad::eOk)

   {

    acutPrintf(L"\nCould not open image ref...");

   }

   else

   {

    AcDbExtents extents;

    pImgReference->getGeomExtents(extents);

 

    acutPrintf(L"\nImage Reference position: [%f, %f, %f]",

     extents.minPoint().x, extents.minPoint().y,

     extents.minPoint().z);

    pImgReference->close();

   }

  } 

 

  pReference->close();

}

 

}

How can you show AModeler hidden line as a dashed line

By Gopinath Taget

Basically, you'll need to add a class that is derived from OutputPolylineCallback and override outputPolyline(). Next, instantiate a callback object in the subViewportDraw() of the custom entity class so it is called when it is HIDE, SHADE or RENDER. Since the callback will give you the hidden edges of a body, if you figure out the correct projection plane, it is just a matter of loading a dashed linetype and displaying the hidden edges in an appropriate LTSCALE.

There is also a trick to force AutoCAD to display the hidden edges. All of the above is fully demonstrated in this sample. Pay special attention to AsdkBody.cpp and .h files, and please be sure to load the sample drawing to test.

CAdUiPaletteSet's keep turning into CAdUiDockControlBars when calling FloatControlBar

By Gopinath Taget

You might find that instances of CAdUiPaletteSet's keep turning into CAdUiDockControlBars when called with FloatControlBar method.

Applications normally manage the state of docking windows (CControlBars) using the standard MFC methods CFrameWnd::DockControlBar(), CFrameWnd::FloatControlBar() and CFrameWnd::ShowControlBar() (Docking windows should not be shown/hidden using calls to CWnd::ShowWindow()). 

Applications can continue to call CFrameWnd::DockControlBar() and CFrameWnd::ShowControlBar() normally. However, when calling CFrameWnd::FloatControlBar(), applications will need to "swap" the floating frame class if the control bar passed to FloatControlBar() is a kind of CAdUiPaletteSet. Applications can perform this "swap" by calling the new method AdUiSetFloatingFrameClass() before and after the call to FloatControlBar():

CRect mRect(100,100, 300, 600);
GetPaletteSet()->InitFloatingPosition(&mRect);

CMDIFrameWnd* pAcadFrame = acedGetAcadFrame();
CRuntimeClass* pCurrentFloatingFrameClass = AdUiSetFloatingFrameClass(RUNTIME_CLASS(CAdUiPaletteSetDockFrame));
acedGetAcadFrame()->FloatControlBar(GetPaletteSet(),CPoint(mRect.left, mRect.top),CBRS_ALIGN_TOP );
AdUiSetFloatingFrameClass(pCurrentFloatingFrameClass);

Why is all of this necessary? MFC's CFrameWnd class caches a pointer to the floating frame class used as a private member of the class. This class pointer is used to instantiate a floating frame for dock control bars when they are floating by CFrameWnd::FloatControlBar(). AdUi needs to continue to support for custom dialogs derived directly from CAdUiControlBar. So AdUi host applications need to use two different floating frame classes, one for those derived from CAdUiControlBar and another for those derived from CAdUiPaletteSet. 

Unfortunately FloatControlBar() is not a virtual method so it is not possible to override it in the application frame class to automatically detect the control bar class and use the correct floating frame. Instead applications must detect the control bar class themselves and manually swap the floating frame class before calling CFrameWnd::FloatControlBar().

Lock a document preventing others from modifying

By Gopinath Taget

If some system variables are valid on a per-document basis, such as CLAYER, and you are modifying a document, some other applications could try to modify it at the same time before your application ends. This could cause CLAYER variable's value to be unreliable for your application. How do you prevent this from happening?

Many system variables such as CLAYER are on a per-document basis. The situation as stated can occur; to avoid this, you'll need to lock the current document that you're working on before you try to modify a per-document system variable such as CLAYER. This way, depending on the lock mode you specify, undesirable modifications can be blocked.

The following code demonstrates how you can add a layer to the current document and set it to be the current layer while preventing other documents from modifying the database. Notice that some error handling code is omitted for code brevity.

// Note: you could place the lock on a broader scope depending on

// your actual needs.

void testLock()

{

Acad::ErrorStatus es;   

 // exclusive write so only you app can write to the document 

 // before you unlock the document 

es = acDocManager->lockDocument(curDoc(), AcAp::kXWrite, NULL,

  NULL,false); 

assert(es == Acad::eOk); 

AcDbDatabase* pDb = curDoc()->database();

AcDbLayerTable* pTable;

es = pDb->getLayerTable(pTable, AcDb::kForRead);  

 const ACHAR layName[] = L"testLayer";   

AcDbLayerTableRecord* pRecord; 

 if(pTable->has(layName))

{

  es = pTable->getAt(layName, pRecord, AcDb::kForRead);   

  assert(es == Acad::eOk);

}   

 else 

{ 

  pRecord = new AcDbLayerTableRecord;   

  pRecord->setName(layName);

  pTable->upgradeOpen();

  es = pTable->add(pRecord);    

  assert(es == Acad::eOk);

} 

AcDbObjectId id = pRecord->objectId();  

pTable->close();  

pRecord->close();

es = curDoc()->database()->setClayer(id); 

assert(es == Acad::eOk);   

es = acDocManager->unlockDocument(curDoc());  

assert(es == Acad::eOk);

}

Setting a plot style name

By Gopinath Taget

You might find that when trying to assign a plot style to a layer using AcDbLayerTableRecord::setPlotStyleName(), it returns "eKeyNotFound" sometimes?

This is because PlotStyles and plotStyleNames are not the same. PlotStyleNames are just entries in the plotStyleName Dictionary (ACAD_PLOTSTYLENAME). They do not rely on the plotStyles in the STB files, nor are they automatically generated by plotStyles. The intent is the opposite of what you might think; the plotStyleName is used as a lookup name when AutoCAD looks for a plotStyle.

When setPlotStyleName returns "Acad::eKeyNotFound", it is indicating that there is no such entry in the plotStyleName Dictionary. To create a desired entry in this dictionary, you can use the AcDbDatabase::getPlotStyleNameDictionary() method to get a pointer to the plotStyleName dictionary (it is an object of class AcDbDictionaryWithDefault type that is derived from AcDbDictionary). You then need to create a new AcDbPlaceHolder object and add it to the plotStyleName dictionary using your desired plotStyleName as the entry's key.

Notice that the plotStyleName dictionary has a default entry "Normal" of AcDbPlaceHolder class. And the setPlotStyleName function returns an error status if the plot style cannot be found in the current plot style table (as this case), or if the drawing's PlotStyleMode is set to use color-based plot styles.

The following code shows how to do this:

static void setNewPlotStyleName()

{   

AcDbDatabase* pDb = curDoc()->database();   

AcDbDictionaryWithDefault* pDict = NULL;   

 

  Acad::ErrorStatus es = pDb->getPlotStyleNameDictionary(pDict,

  AcDb::kForWrite);   

 if(es != Acad::eOk)       

  return;   

AcDbPlaceHolder* pNewHolder = new AcDbPlaceHolder;   

 if(!pNewHolder)   

{       

  pDict->close();       

  return;   

}   

AcDbObjectId newId;   

 const TCHAR newStyleName[] = _T("Sample plot style name");   

es = pDict->setAt(newStyleName, pNewHolder, newId);   

 if(es != Acad::eOk)   

{       

  delete pNewHolder;       

  pDict->close();       

  return;   

}   

 

 // close the new object   

pNewHolder->close();   

 // set the defaultId to be the new one   

 // you don't have to do this but this is to demonstrate   

 // that you can    

es = pDict->setDefaultId(newId);   

 if(es != Acad::eOk)   

{       

  // since it is already database resident       

  // we can only erase it       

  es = acdbOpenAcDbObject((AcDbObject *&)pNewHolder, newId,

   AcDb::kForWrite);       

  assert(es == Acad::eOk);       

  pNewHolder->erase();       

  pNewHolder->close();       

  pDict->close();       

  return;   

}   

pDict->close();   

 // open the current layer table record   

AcDbLayerTableRecordPointer pLayerBtr(pDb->clayer(),

  AcDb::kForWrite);   

es = pLayerBtr.openStatus();   

 if(es == Acad::eOk)   

{       

  // set its plot style name       

  es = pLayerBtr->setPlotStyleName(newStyleName);       

  if(es != Acad::eOk)           

   acutPrintf(_T("Error setting plot style name %s."),

   newStyleName);   

}

}

//// This should always work as long as

// someone has not altered the "Normal" name programmatically.

// Again this is for companion demonstration purpose.

//

static void setDefaultPlotStyleName()

{   

 const TCHAR styleName[] = _T("normal");   

AcDbDatabase* pDb = curDoc()->database();   

 // open the current layer table record   

AcDbLayerTableRecordPointer pLayerBtr(pDb->clayer(),

  AcDb::kForWrite);   

Acad::ErrorStatus es = pLayerBtr.openStatus();   

 if(es == Acad::eOk)   

{       

  // set its plot style name       

  es = pLayerBtr->setPlotStyleName(styleName);       

  if(es != Acad::eOk)           

   acutPrintf(_T("Error setting plot style name %s."),

   styleName);   

}

}

Making non-database resident objects work with undo

By Gopinath Taget

Non-database resident objects do not participate in an Undo/Redo. However, it is fairly easy to take advantage of the built-in Undo/Redo feature with the following procedure:

1. Derive your objects from AcDbObject as if you were creating a custom database-resident object. (You will only need to override the dwgInFields/dwgOutFields methods.)
2. Append the objects to the database using AcDbDatabase::addAcDbObject

The addAcDbObject function appends the object to the database but does not set up an owner for the object so it will not be saved when the database is saved.

You will need to use proper open/close protocol on this object to ensure undo/redo works as expected.

Programmatically saving the active document in C++/ARX applications

By Gopinath Taget

Use the Automation interfaces inside your ARX application. The following code samples demonstrate two approaches to consider (Make sure your ARX projects supports the AutoCAD ActiveX client interfaces. The ARX wizard makes this easy to do):

First Approach:

void saveDwg()

{

 try

{

IAcadApplicationPtr pApp =

acedGetAcadWinApp()->GetIDispatch(FALSE);

IAcadDocumentPtr pDoc;

pApp->get_ActiveDocument(&pDoc);

pDoc->Save();

}

 catch(_com_error& e)

{

acutPrintf(_T("\nCOM error: %s"), (ACHAR*)e.Description());

}

}

Second Approach:

#include <acadi_i.c>

// minimal error check for code brevity

void saveDwg()

{

CWinApp* pWinApp = acedGetAcadWinApp();

 if(!pWinApp)

  return;

CComPtr<IDispatch> pDisp = pWinApp->GetIDispatch(TRUE);

 if(!pDisp)

  return;

 

CComPtr<IAcadApplication> pComApp;

HRESULT hr = pDisp->QueryInterface(IID_IAcadApplication,

  (void**)&pComApp);

 if(FAILED(hr))

  return;

 

CComPtr<IAcadDocument> pDoc;

hr = pComApp->get_ActiveDocument(&pDoc);

 if(FAILED(hr))

  return;

 

hr = pDoc->Save();

 if(FAILED(hr))

  acutPrintf(_T("\nFailed to save current dwg file."));

}

Use the normal to correct the text when mirroring a dimension with transformBy

By Gopinath Taget

While applying the transformBy() method on a dimension entity, the dimension text also gets mirrored and does not respect the MIRRTEXT system variable. To avoid this behavior, store the normal of the dimension entity before mirroring and then apply it to the mirrored entity as shown in the sample code below:

NOTE: Error handling has been kept short for clarity.

void ASDKtest()

{

ads_name ent;

ads_point ptres;

acedEntSel( L"\nSelect a dimension entity: ", ent, ptres );

 

AcDbObjectId objId;

acdbGetObjectId(objId, ent);

 

AcDbEntity * pEnt = NULL;

acdbOpenObject(pEnt, objId, AcDb::kForWrite);

 

AcDbDimension * pDim = NULL;

pDim = AcDbDimension::cast(pEnt);

 if(!pDim)

{   

  acutPrintf(L"\nPlease select a Dimension");

  pEnt->close();

  return;

}

 

AcGeVector3d norm;

norm = pDim->normal();

 

AcGeMatrix3d mat;

mat.setToIdentity();

AcGeLine3d line(AcGePoint3d(7,7,0), AcGePoint3d(7,0,0));

mat.setToMirroring(line);

 

pDim->transformBy(mat);

pDim->setNormal(norm);

pDim->close();

}