calculating area of polyline

[slbarker]

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,

[support]

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

[support]

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