General API Question

[Anonymous]

I'm going through a lot of the documentation and trying to understand things before I attempt anything very serious and I am having a hard time grasping exactly how everything works. It seems that several of the examples utilize the following classes to access AutoCAD:

AutoCAD::IAcadApplication *pAcad;
AutoCAD::IAcadDocument *pDoc;
AutoCAD::IAcadDatabase *pDb;

But there is little to no documentation on them. In fact, there is not a single reference to IAcadDocument in any of the documentation. Am I just missing it? What are these used for?

It also appears that most of the other samples use the following classes to interact with AutoCAD:

AcApDocument* pDoc;

AcDbDatabase* pDb;

The actual plugin that I am wiriting is going to be exporting a drawing to a WMF, but I'm not sure which of the above approaches I should take. The only function that I can find to do it is the AutoCAD::IAcadDocument.Export(). Is this the best way to perform this operation? Any help would be appreciated, Thanks!

[owenwengerd]

Those are just pointers to COM interfaces, so you'll want documentation for the underlying COM interfaces (probably in the VBA section of the developer reference). The Export() function is probably your best bet.

[Anonymous]

Thanks, that makes sense. The problem with the export function is that it requires a IAcadSelectionSet. I can't find anyway to create one. It seems that it would be useful to call

acedSSGet(_T("_A"), NULL, NULL, filter, m_ss);

but all that would give me would be a ads_name and I'm not sure how I could create a IAcadSelectionSet from that.

[Alexander.Rivilis · Accepted solution]

Sample:

IAcadSelectionSet *GetOrCreateSelectionSet(IAcadSelectionSets *pSelSets, BSTR Name)
{
  try {
    IAcadSelectionSet *pSet = NULL;
    if (pSelSets->Add(Name,&pSet) == S_OK) {
      return pSet;
    } else if (pSelSets->Item(_variant_t(Name),&pSet) == S_OK) {
      return pSet;
    } else return NULL;
  } catch(...) {
    return NULL;
  }
  return NULL;
}
int ExportToFile(const wstring &filename, const wstring &ext)
{
  HRESULT hr;
  try
  {
    IAcadApplication *pAppAcad = (IAcadApplication *)acedGetAcadWinApp()->GetIDispatch(TRUE);
    if (pAppAcad) {
      IAcadDocument *pAcadDoc = NULL; 
      if (pAppAcad->get_ActiveDocument(&pAcadDoc) == S_OK) {
        IAcadSelectionSets *pSelSets = NULL;
        if (pAcadDoc->get_SelectionSets(&pSelSets) == S_OK) {
          IAcadSelectionSet *pSet = NULL;
          if ((pSet = GetOrCreateSelectionSet(pSelSets,_bstr_t("$$PLOTSET$$"))) != NULL) {
            pSet->Clear();
            if (FAILED(hr = pSet->Select(acSelectionSetAll,vtMissing,vtMissing,vtMissing,vtMissing))) throw(_com_error(hr)) ;
            if (FAILED(hr = pAcadDoc->Export(_bstr_t(filename.c_str()),_bstr_t(ext.c_str()),pSet))) throw(_com_error(hr)) ;
            pSet->Release();
          } else return 0;
          pSelSets->Release();
        }
        pAcadDoc->Release();
      }
      pAppAcad->Release();
    }
  }
  catch (...)
  {
    return 0;
  }
  return 1;
}

[Anonymous]

Thanks a lot! This was a huge help and clearly set me on the right direction. Thanks again.