CADSoftTools

Posted: **28 Nov 2006, 13:46**

Where can I get more information about TsgDXFPolyline? I need more information about it's shape. I am trying to use information from dwg file in c++ code. I tried extracting information on polyline by using Entities, but all I get are the first and the last point of the polyline. Can you tell me how I could get more information about its shape?

Posted: **28 Nov 2006, 17:53**

Hello Branka,

1. CADImportVCL (available at: http://www.cadsofttools.com/download/cadimportvcl.zip) contains respective documentation. Please find it in the ..\cadimportvcl\Doc\.. folder of the package.

2. The following example shows how to get vertexes of the polyline:

Unit1.cpp

Code: Select all

...
<font color="green">#include "Unit1.h"</font id="green">
<font color="blue">//---------------------------------------------------------------------------</font id="blue">
...
<font color="green">#pragma link "SGImage"</font id="green">
...

//---------------------------------------------------------------------------

<b>void __fastcall</b> TForm1::Button1Click(TObject *Sender)
{
  TsgDXFVertex *Vertex;
  TsgDXFPolyline *Poly;
  TsgDXFConverter *Conv;
  TsgDXFEntity *Ent;
  AnsiString S = <font color="blue">""</font id="blue">;

  <b>if</b> (!OpenDialog1->Execute()) <b>return</b>;

  sgImage1->LoadFromFile(OpenDialog1->FileName);

  FImg = <b>dynamic_cast</b><TsgDXFImage *>(sgImage1->Picture->Graphic);

  Conv = <b>dynamic_cast</b><TsgDXFConverter *>(FImg->Converter);
  <b>int</b> cnt = Conv->Sections[csEntities]->Count;
  <b>for</b> (<b>int</b> i = <font color="blue">0</font id="blue">; i < cnt; i++)
  {
    Ent = <b>dynamic_cast</b><TsgDXFEntity *>(Conv->Sections[csEntities]->Entities[i]);
    <b>if</b> (Ent->ClassType() == __classid(TsgDXFPolyline))
    {
      Poly = dynamic_cast<TsgDXFPolyline *>(Conv->Sections[csEntities]->Entities[i]);
      <b>for</b> (<b>int</b> j = <font color="blue">0</font id="blue">; j < Poly->Count; j++)
      {
        Vertex = dynamic_cast<TsgDXFVertex *>(Poly->Entities[j]);
        S = S + <font color="blue">"Vertex "</font id="blue"> + IntToStr(j) + <font color="blue">"\n"</font id="blue"> +
         <font color="blue">" X = "</font id="blue"> + FloatToStr(Vertex->Point.X) + <font color="blue">"\n"</font id="blue"> +
         <font color="blue">" Y = "</font id="blue"> + FloatToStr(Vertex->Point.Y) + <font color="blue">"\n"</font id="blue"> + 
         <font color="blue">" Z = "</font id="blue"> + FloatToStr(Vertex->Point.Z) + <font color="blue">"\n"</font id="blue">;
      }
      ShowMessage(S);
    }
  }
}
<font color="blue">//---------------------------------------------------------------------------</font id="blue">

Unit1.h

Code: Select all

...
//---------------------------------------------------------------------------
...
<font color="green">#include "SGImage.hpp"
#include "DXFImage.hpp"
#include "DXFConv.hpp"</font id="green">
...
//---------------------------------------------------------------------------
<b>class</b> TForm1 : <b>public</b> TForm
{
__published:	// IDE-managed Components
        ...
        TsgImage *sgImage1;
        TButton *Button1;
        TOpenDialog *OpenDialog1;
        void __fastcall Button1Click(TObject *Sender);
<b>private:</b>	// User declarations
        TsgDXFImage *FImg;
...
};
//---------------------------------------------------------------------------
...

Sergey.

please post questions to the forum or write to support@cadsofttools.com

Posted: **28 Nov 2006, 20:50**

Thanks for the reply. I have another question. It says in the help that polyline is made up from arcs and lines and that vertexes are end points of those arcs and lines. I was wondering how i could get more information about the arc, its curvature.

Thanks in advance

Posted: **29 Nov 2006, 16:38**

Hello Branka,

There two ways:
<ul><li>Easy one:
use the following property:
__property Classes::TList* DottedSingPts = {read=FDottedSingPts};

Contains coordinates of the polyline as a list of the pointers to TFPoint type.</li>
<li>Difficult one:
It is nescessary to analize Bulge property of every vertex received from the TsgDXFPolyline.Entities list.
AutoCAD documantion says:
<blockquote id="quote">quote:<hr height="1" noshade id="quote">The bulge is the tangent of one fourth the included angle for an arc segment, made negative if the arc goes clockwise from the start point to the endpoint. A bulge of 0 indicates a straight segment, and a bulge of 1 is a semicircle.<hr height="1" noshade id="quote"></blockquote id="quote">
Basing on this information polyline has to be built.
</li></ul>
Sergey.

please post questions to the forum or write to support@cadsofttools.com