AutoCAD DevBlog

Use log file and SETVAR command to get a list of AutoCAD system variables

By Wayne Brill

You may want to output the system variables to a text file. This VB.NET example turns the log file on and runs the SETVAR command. The QAFLAGS setting of 2 enables the command to complete without having to hit Enter multiple times.

<CommandMethod("saveTheVars")> _

Public Sub saveVars()

    Dim strLogFileName As String = _

      Application.GetSystemVariable("LOGFILENAME")

 

    MsgBox("Varibles saved in " & strLogFileName)

 

    ' Setting QAFLAGS to 2 allows you to avoid

    ' hitting enter multiple times

    Application.SetSystemVariable("QAFLAGS", 2)

 

    Application.DocumentManager.MdiActiveDocument _

        .SendStringToExecute _

              ("_.LOGFILEON ", False, False, False)

 

    Dim strCmd As String

    strCmd = _

"(command" & """_setvar""" & """?""" & """*""" & ")" _

      & vbCrLf

 

    Application.DocumentManager.MdiActiveDocument. _

        SendStringToExecute _

                        (strCmd, False, False, False)

 

    Application.DocumentManager.MdiActiveDocument. _

        SendStringToExecute _

               ("_.LOGFILEOFF ", False, False, False)

 

End Sub

The “correct” way to use AutoCAD acedCmd() acedCommand() in ObjectARX, .NET, or LISP

by Fenton Webb

By now, if you have been following my posts, will have probably realized that I really do like acedCmd and acedCommand (command in LISP).

I wanted to write an tell you how you should format the command strings and keywords that you pass to these functions,

Firstly, let’s talk about the Command strings themselves. AutoCAD comes in many languages, and the Command strings are actually translated for each language. This means that we can never assume the English LINE command will be called the same in the Russian version, for instance. As a programmer, one that uses acedCmd or acedCommand, we don’t really want to worry ourselves about localized Command strings. Thankfully, we can always access the English (non-localized version of any Command string by using the underscore symbol… e.g.

_LINE

Another issue that programmers like us don’t want to worry ourselves with when using acedCmd or acedCommand is whether or not the user has REDEFINE’d one of the Commands that we want to use… If they have, they could cause our lovely program to fail because they have changed the way the command we are using works – costing us support calls!! Thankfully, we can always access the raw Command using …. e.g.

.LINE

You can combine both of these tricks together… e.g.

_.LINE

in roundup, the “correct” way to specify Command Strings using acedCmd and acedCommand is: prefix all Commands with _.

Finally, let’s talk about the keyword strings that you pass to acedCmd or acedCommand. Again, these are localized, again we don’t want to worry about running into keywords that are different on different localized versions of AutoCAD, so we can use the underscore technique... (note you cannot REDEFINE keywords, so there is no dot required)… e.g.

_Startpoint

You’ll notice that I have specified the whole keyword string, not just _S. Why I recommend that you do this is is purely from experience…

1) Commands can change in the future, if you specify _S then later on, we introduce a new keyword called _Separate, then your code is broken. Always use the full keyword, it will save you time and effort in the future.

2) It’s easier to read in your code… You’ll be glad of this years down the line when you are trying to remember what the command is doing.

PaletteSet minimum docked width

By Adam Nagy

I have a PaletteSet that contains a toolbar and its width is set to 40 pixels. This works fine in AutoCAD 2008, but in AutoCAD 2011 I cannot make the width smaller than 150 pixels when the PaletteSet is docked.

Solution

In AutoCAD 2009 the minimum docked width of dockable windows including PaletteSets has been changed from 40 to 150 pixels and it is so in AutoCAD 2011 as well.

In AutoCAD 2012 however a new ARX function is being introduced which can override this value:

bool AdUiSetDockBarMinWidth(int width)

You can also use it from .NET via P/Invoke:

public class Commands

{

  PaletteSet ps;

 

  // The function signature passed in for EntryPoint

  // is different in case of AutoCAD x64

  [DllImport(

    "adui18.dll", CallingConvention = CallingConvention.Cdecl,

    EntryPoint = "?AdUiSetDockBarMinWidth@@YA_NH@Z")]

  public static extern bool AdUiSetDockBarMinWidth(int width);

 

  [CommandMethod("MyPalette")]

  public void MyPalette()

  {

    AdUiSetDockBarMinWidth(40);

 

    if (ps == null)

    {

      ps = new PaletteSet("My Palette 1");

      ps.MinimumSize = new System.Drawing.Size(30, 300);

      ps.Dock = DockSides.Top;

      MyControl1 myCtrl = new MyControl1();

      myCtrl.Dock = System.Windows.Forms.DockStyle.Fill;

      ps.Add("test", myCtrl);

    }

    ps.Visible = true;

  }

}

How to use threads in ObjectARX?

By Adam Nagy

How do I call an AutoCAD command from a background thread? When I try to call AcApDocManager::sendStringToExecute(), it causes AutoCAD to terminate unexpectedly.

Solution

The AutoCAD API functions are not thread safe - i.e. they do not expect to be called from a thread other than the main one.

You can create your own threads for background processing, but if you need to call an ARX function (even just to execute an AutoCAD command), then you need to marshal that call to the main thread.

We have a DevNote on this topic concerning .NET AddIns called "Use Thread for background processing", and you can handle this situation in ARX in a similar fashion.

You could write a helper class that creates a message only window, that could be used to invoke AutoCAD functions on the main thread.

class MyInvoker

{

public:

  MyInvoker()

  {

    WNDCLASS wndclass = {0};

    wndclass.hInstance     = _hdllInstance ;

    wndclass.lpfnWndProc   = wndProcedure;

    wndclass.lpszClassName = L"MessageOnlyWindow";

 

    // Register the class

    ATOM a = RegisterClass(&wndclass);

 

    // Create the window object

    _hwnd = CreateWindow(L"MessageOnlyWindow",

      NULL,

      NULL,

      CW_USEDEFAULT,

      CW_USEDEFAULT,

      CW_USEDEFAULT,

      CW_USEDEFAULT,

      NULL,

      NULL,

      _hdllInstance,

      NULL);

  }

 

  ~MyInvoker()

  {

    DestroyWindow(_hwnd);

  }

 

  typedef void (*CallbackFunctionType)();

  void InvokeSync(CallbackFunctionType funcPtr)

  {

    SendMessage(_hwnd, _wm, 0, (LPARAM)funcPtr);

  }

 

private:

  HWND _hwnd;

  static DWORD _wm;

  static LRESULT CALLBACK wndProcedure(

    HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)

  {

    if (Msg == _wm)

    {

      CallbackFunctionType funcPtr = (CallbackFunctionType)lParam;

      (*funcPtr)();

    }

 

    return DefWindowProc(hWnd, Msg, wParam, lParam);

  }

};

DWORD MyInvoker::_wm = RegisterWindowMessage(L"MyInvokeMessage");

// a global instance of the helper class

MyInvoker * g_myInvoker;

Create an instance of this class in the kInitAppMsg

virtual AcRx::AppRetCode On_kInitAppMsg (void *pkt)

{

  // TODO: Load dependencies here

 

  // You *must* call On_kInitAppMsg here

  AcRx::AppRetCode retCode =AcRxArxApp::On_kInitAppMsg(pkt);

 

  // TODO: Add your initialization code here

  g_myInvoker = new MyInvoker();

 

  return (retCode) ;

}

And delete it in the kUnloadAppMsg

virtual AcRx::AppRetCode On_kUnloadAppMsg (void *pkt)

{

  // TODO: Add your code here

 

  // You *must* call On_kUnloadAppMsg here

  AcRx::AppRetCode retCode =AcRxArxApp::On_kUnloadAppMsg(pkt);

 

  // TODO: Unload dependencies here

  delete g_myInvoker;

 

  return (retCode) ;

}

You would need to place the ARX calls into a seperate function that then could be invoked on the main thread. Note that now we are in session/application context so if you wanted to modify the database you would need to lock the document

void acadFunctionCalls()

{

  AcApDocument * activeDoc = acDocManager->mdiActiveDocument();   

 

  acDocManager->sendStringToExecute(

    activeDoc,

    L"\x03\x03(command \"LINE\" \"0,0\" \"100,100\" \"\") "); 

}

Here is the function that the background thread will execute

UINT thread( LPVOID pParam )

{

  // we are doing some calculations in the thread

  Sleep(3000);

 

  // now we want to call some AutoCAD functions

  g_myInvoker->InvokeSync(acadFunctionCalls);

 

  return (0);  //exit from thread       

}

And here is the AutoCAD command that will start the background thread

static void MfcThreadTest_StartThread(void)

{

  AfxBeginThread(thread,NULL,THREAD_PRIORITY_LOWEST);

}

Identify attribute definitions in blocks

By Virupaksha Aithal

Attributes definitions are stored along with all the entities which constitute the block table record. But when a reference is added to block, the a corresponding references (Attributes reference) containing Attributes definitions are added. One way to identify the presence of Attributes definitions is by checking the block table record API “BlockTableRecord .HasAttributeDefinitions”.

 [CommandMethod("AttributeDefTest")]

 static public void AttributeDefTest()

 {

     Document doc = Application.DocumentManager.MdiActiveDocument;

     Database db = doc.Database;

     Editor ed = doc.Editor;

 

     PromptStringOptions opts =

        new PromptStringOptions("Enter block name");

     opts.AllowSpaces = true;

 

     PromptResult blockName = ed.GetString(opts);

 

     if (blockName.Status != PromptStatus.OK)

         return;

 

     using (Transaction tx =

                         db.TransactionManager.StartTransaction())

     {

         BlockTable blockTable = tx.GetObject(db.BlockTableId,

                                    OpenMode.ForRead) as BlockTable;

 

         if (blockTable.Has(blockName.StringResult))

         {

             BlockTableRecord block = tx.GetObject(

                              blockTable[blockName.StringResult],

                             OpenMode.ForRead) as BlockTableRecord;

             bool bAttDef = block.HasAttributeDefinitions;

 

             if (bAttDef)

             {

                 ed.WriteMessage("Block" + block.Name +

                             " contains attribute definiations\n");

             }

             else

             {

                 ed.WriteMessage("Block" + block.Name +

                     " does not contains attribute definiations\n");

             }

 

         }

         tx.Commit();

     }

 }

Traversing through attribute references in Mleader

By Virupaksha Aithal

Mleader entity allows users to set the block (including user defined custom block) as the content type. Many times, these blocks contain attribute definitions and hence Mleader maintains attribute references to the contained attribute definitions of the block table record.  Below code show the procedure to get the attribute reference for selected Mleader.

[CommandMethod("mLeaderBlockTest")]

public void mLeaderBlockTest()

{

    Document doc = Application.DocumentManager.MdiActiveDocument;

    Database db = doc.Database;

    Editor ed = doc.Editor;

 

    PromptEntityOptions options =

            new PromptEntityOptions("\nSelect a Mleader with block");

    options.SetRejectMessage("\nSelect only Mleader with block");

    options.AddAllowedClass(typeof(MLeader), false);

 

    PromptEntityResult acSSPrompt = ed.GetEntity(options);

 

    if (acSSPrompt.Status != PromptStatus.OK)

        return;

 

    using (Transaction Tx = db.TransactionManager.StartTransaction())

    {

        //get the mleader

        MLeader mleader = Tx.GetObject(acSSPrompt.ObjectId,

                                   OpenMode.ForRead) as MLeader;

 

        ObjectId blockId = mleader.BlockContentId;

        if (blockId == ObjectId.Null)

        {

            ed.WriteMessage("Mleader does not contains block\n");

            return;

        }

 

        BlockTableRecord record = Tx.GetObject(blockId,

                               OpenMode.ForRead) as BlockTableRecord;

 

        if(!record.HasAttributeDefinitions)

        {

            ed.WriteMessage("No attributes in block\n");

            return;

        }

        foreach (ObjectId Id in record)

        {

            DBObject dbObj = Tx.GetObject(Id, OpenMode.ForRead) ;

 

            if (dbObj is AttributeDefinition)

            {

                AttributeDefinition attDef =

                                        dbObj as AttributeDefinition;

                using (AttributeReference attRef =

                                      mleader.GetBlockAttribute(Id))

                {

                    ed.WriteMessage("Reference text for tag " +

                     attDef.Tag + " is " + attRef.TextString + "\n");

                }

            }

        }

 

        Tx.Commit();

    }

 

}

Locking an Entity in AutoCAD using ObjectARX

By Balaji Ramamoorthy

Here are few ways to lock entities in drawing, so that the user can't move or do any kind of operations to them. It allows some objects to be locked and some not, in same drawing.

The best way to do this is to use overrule. The "AcDbTransformOverrule" can be used to prevent any transformation (Move, Rotate, Scale etc) from affecting the entity. The "AcDbGripOverrule" can be used to remove the default grips that appear on the entity. This will prevent the entity from being grip edited. Here is a sample code snippet to prevent circles in the drawing from getting transformed :

Step 1: Implement a Transform overrule

#include "dbentityoverrule.h"

 

class CTransformOverrule: public AcDbTransformOverrule

{

public:

 

    static CTransformOverrule* _pTheOverrule;

    ACRX_DECLARE_MEMBERS(CTransformOverrule);

 

    bool isApplicable(const AcRxObject* pOverruledSubject) const

    {

        return true;

    }

 

    Acad::ErrorStatus transformBy(

                                    AcDbEntity* pSubject,

                                    const AcGeMatrix3d& xform

                                )

    {

        if(pSubject->isA() != AcDbCircle::desc())

            return Acad::eOk;

 

        AcDbCircle* pCircle = AcDbCircle::cast(pSubject);

        if(pCircle != NULL)

            return Acad::eNotApplicable;

 

        return AcDbTransformOverrule::transformBy(pSubject, xform);

    }

 

    // Take care about calling "CTransformOverrule::rxInit();"

    // in "On_kInitAppMsg" of the arx that uses this overrule.

    static void CTransformOverrule::AddOverrule()

    {

        if(_pTheOverrule != NULL)

            return;

 

        _pTheOverrule = new CTransformOverrule();

 

        AcRxOverrule::addOverrule(

                                    AcDbCircle::desc(),

                                    _pTheOverrule,

                                    true

                                 );

 

        CTransformOverrule::setIsOverruling(true);

    }

 

    static void CTransformOverrule::RemoveOverrule()

    {

        if(_pTheOverrule == NULL)

            return;

 

        CTransformOverrule::setIsOverruling(false);

 

        AcRxOverrule::removeOverrule(

                                        AcDbCircle::desc(),

                                        _pTheOverrule

                                    );

        delete _pTheOverrule;

 

        _pTheOverrule = NULL;

    }

};

 

CTransformOverrule* CTransformOverrule::_pTheOverrule = NULL;

 

ACRX_NO_CONS_DEFINE_MEMBERS(CTransformOverrule, AcDbTransformOverrule);

Step 2 : Implement a Grip overrule

class CGripOverrule: public AcDbGripOverrule

{

public:

 

    static CGripOverrule* _pTheOverrule;

    ACRX_DECLARE_MEMBERS(CGripOverrule);

 

    bool isApplicable(const AcRxObject* pOverruledSubject) const

    {

        return true;

    }

 

    //Add the overrule.

    //Take care about calling "CGripOverrule::rxInit();"

    // in "On_kInitAppMsg" of the arx that uses this overrule.

    static void CGripOverrule::AddOverrule()

    {

        if(_pTheOverrule != NULL)

            return;

 

        _pTheOverrule = new CGripOverrule();

 

        AcRxOverrule::addOverrule(AcDbCircle::desc(), _pTheOverrule, true);

 

        CViewportDrawOverrule::setIsOverruling(true);

    }

 

    static void CGripOverrule::RemoveOverrule()

    {

        if(_pTheOverrule == NULL)

            return;

 

        CGripOverrule::setIsOverruling(false);

 

        AcRxOverrule::removeOverrule(AcDbCircle::desc(), _pTheOverrule);

 

        delete _pTheOverrule;

 

        _pTheOverrule = NULL;

    }

 

    Acad::ErrorStatus CGripOverrule::getGripPoints(const AcDbEntity* pSubject,

                                AcGePoint3dArray&  gripPoints,

                                AcDbIntArray &     osnapModes,

                                AcDbIntArray &  geomIds)

    {

        AcDbCircle* pCircle = AcDbCircle::cast(pSubject);

        if(pCircle != NULL)

        {// Remove the grip points, for a circle

            gripPoints.removeAll();

            return Acad::eNotApplicable;

        }

 

        return AcDbGripOverrule::getGripPoints(pSubject, gripPoints, osnapModes, geomIds);

    }

 

    Acad::ErrorStatus CGripOverrule::getGripPoints

                            (

                                const AcDbEntity* pSubject,

                                AcDbGripDataPtrArray& grips,

                                const double curViewUnitSize,

                                const int gripSize,

                                const AcGeVector3d& curViewDir,

                                const int bitflags

                            )

    {

        AcDbCircle* pCircle = AcDbCircle::cast(pSubject);

        if(pCircle != NULL)

        {// Remove the grip points, for a circle

            grips.removeAll();

            return Acad::eNotApplicable;

        }

 

        return AcDbGripOverrule::getGripPoints

                                            (

                                                pSubject,

                                                grips,

                                                curViewUnitSize,

                                                gripSize,

                                                curViewDir,

                                                bitflags

                                            );

    }

};

 

CGripOverrule* CGripOverrule::_pTheOverrule = NULL;

 

ACRX_NO_CONS_DEFINE_MEMBERS(CGripOverrule, AcDbGripOverrule);

Step 3 : Ensure that our overrule classes are part of the class hierarchy.

virtual AcRx::AppRetCode On_kInitAppMsg (void *pkt)

{

    AcRx::AppRetCode retCode = AcRxArxApp::On_kInitAppMsg (pkt) ;

 

    CGripOverrule::rxInit();

    CTransformOverrule::rxInit();

    acrxBuildClassHierarchy();

 

    return (retCode) ;

}

Step 4 : Add commands to enable / disable the overruling

// Command to enable overruling

static void asdkOverrule_Start(void)

{

    CTransformOverrule::AddOverrule();

    CGripOverrule::AddOverrule();

}

 

// Command to disable overruling

static void asdkOverrule_Stop(void)

{

    CTransformOverrule::RemoveOverrule();

    CGripOverrule::RemoveOverrule();

}

Use getClosestPointTo() and onSegAt() to locate a polyline vertex near a point

By Wayne Brill

You can use getClosestPointTo() and onSegAt() to find a vertex of a polyline closest to a selected point. Here is an ObjectARX example that shows this idea. To try this run a command that runs this function. If you select a polyline the command line will display the number of the segment of the polyline (where you selected the polyline).

 static void TEST_PointOnPoly(void)

{

 

  ads_name ename;

  ads_point pt, ptWcs;

  AcDbObjectId Id;

 

  if(acedEntSel(_T("Select Pline: "),

                      ename,pt)!=RTNORM)

   return;

 

  // Convert to WCS incase selection was made

  // while in a UCS.

  acdbUcs2Wcs(pt, ptWcs, Adesk::kFalse);

  acdbGetObjectId(Id,ename);

  AcDbEntity* pEnt;

  acdbOpenObject(pEnt,Id,AcDb::kForRead,false);

 

  AcDbPolyline* pLine=NULL;

  pLine=AcDbPolyline::cast(pEnt);

 

  if(!pLine)

  {

   acutPrintf(_T

    ("Selected Entity not a Polyline"));

   pEnt->close();

   return;

  }

 

  AcGePoint3d clickpt;

  // This will convert the pick point to a

  // point on the polyline

  pLine->getClosestPointTo(asPnt3d(ptWcs), clickpt);

  // Convert to 2d point, needed below...

  AcGePoint2d clickpt2d(clickpt.x, clickpt.y);

 

  for(unsigned int c=0; pLine->numVerts() > c ; c++)

  {

   double segParam;

   // This is the test filter here...it uses the

   // nifty API onSegAt

   if(pLine->onSegAt(c, clickpt2d, segParam)) 

   {

    acutPrintf(_T("Selected Segment: %d \n"),c+1);

    break;

   }

  }

  pLine->close();

}

Displaying Modal and Modeless forms in AutoCAD .NET

By Stephen Preston

Another in my occasional series of common beginner mistakes that take forever and a day to debug .

Sometimes what we already know gets in the way. If you want to display a form in .NET, you use Form.ShowDialog. Right?

Wrong! If you do, you’re likely to find AutoCAD hanging or displaying other unexpected behavior – particularly if you’re doing this in conjunction with VBA macros. Instead display your dialogs using the AutoCAD .NET APIs provided for the purpose:

• Application.ShowModalDialog
• Application.ShowModelessDialog

And if you’re working with modeless dialogs, consider using a palette instead. Kean Walmsley explains why that’s a good idea here.

Error with Visual LISP editor when debugging from .NET

By Wayne Brill

When debugging from a .NET and running the VLIDE an error may occur. A work around is to change a registry setting. (MDA - Managed Debugging Assistants = 0). To set this registry key use a tool like regedit and set the string key "MDA" to 0.

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework  

If you do not find the MDA string key, create one and set its value to 0.

 

You could also create a .reg file and set its contents as follows:

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework]
"MDA"="0"