CADSoftTools

Posted: **03 Nov 2005, 23:43**

There doesn't seem to be a property or method to show the area of a closed polyline.

Does anyone have any code to do this?

thanks,

Posted: **07 Nov 2005, 11:10**

Hello,

It is necessary to use a mathematical algorithm. We shall try to find it and to implement it in our demo. So you will be able to use it.

Sergey.

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

Posted: **08 Nov 2005, 19:09**

Hello!

The following code can be implemented with CADImportVCL (available on: http://www.cadsofttools.com/download/CADImportVCL.zip). It allows counting of the area inside of closed polyline.
Delphi code:

Code: Select all

<b>function</b> GetArea(APolygon: TsgDXFPolyline): Double;
<b>var</b>
  I, Cnt, J: Integer;
  Pt: <b>array</b> [0 .. 1] <b>of</b> PFPoint;
<b>begin</b>
  Result := 0.0;
  Cnt := APolygon.PolyPoints.Count;
  <b>if</b> Cnt >= 3 <b>then</b>
  <b>begin</b>
    J := 1;
    Pt[J] := PFPoint(APolygon.PolyPoints.Items[Cnt - 1]);
    <b>for</b> I := 0 <b>to</b> Cnt - 1 <b>do
    begin</b>
      J := J <b>xor</b> 1;
      Pt[J] := PFPoint(APolygon.PolyPoints.Items[I mod Cnt]);
      Result := Result + (Pt[J]^.X + Pt[J <b>xor</b> 1]^.X) * (Pt[J]^.Y - Pt[J <b>xor</b> 1]^.Y);
    <b>end</b>;
    Result := Abs(Result) * 0.5;
  <b>end</b>;
<b>end</b>;

Sergey

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

CADSoftTools

calculating area of polyline

calculating area of polyline