procedure TWebModule1.WebModule1waDrawChartAction(Sender: TObject;
  Request: TWebRequest; Response: TWebResponse; var Handled: Boolean);
begin
  { The Query String for this action should be of the Format :
    Title=xxxx&Bar1Title=Bar1Value&Bar2Title=Bar2Value....
    If "Titles" has "spaces" then they should be replaced with "_" (underscore)
    this pertains to all titles
  }
  Response.ContentType := 'image/jpeg';
  Response.ContentStream := GenerateChart;
  Response.SendResponse;
end;

function TWebModule1.GenerateChart : TMemoryStream;
var
  ChartTitle : string;
  NoOfBars   : Integer;
  BarTitles  : array of string;
  BarValues  : array of Integer;
  i          : Integer;
  MemStrm    : TMemoryStream;
begin
  MemStrm := TMemoryStream.Create;
  try
  { No of Bars is 1 less than count, since TITLE is the first parameter }
  NoOfBars := Request.QueryFields.Count -1;
  { Set the size of the dynamic arrays }
  SetLength(BarTitles,NoOfBars);
  SetLength(BarValues, NoOfBars);
  { Get the Title of the Chart }
  ChartTitle := StringReplace(Request.QueryFields.Values['Title'],'_',' ',[rfReplaceAll]);
  { Start from 1 since we don't need the Chart Title here }
  for i := 1 to Request.QueryFields.Count -1 do
  begin
    { Don't Remove the underscores as yet ! }
    { Dynamic arrays are zero based ! }
    BarTitles[i-1] := Request.QueryFields.Names[i];
    BarValues[i-1] := StrToInt(Request.QueryFields.Values[BarTitles[i-1]]);
  end;
  { We now have a populated arrays of Bar Titles and their respective values }
  finally
  end;
  DrawChart(MemStrm, ChartTitle, BarTitles, BarValues);
  Result := MemStrm;
end;

procedure TWebModule1.DrawChart(var MemStream : TMemoryStream;ChartTitle: string;
  BarTitles: array of string; BarValues : array of Integer);
var
  HorizBarSeries : THorizBarSeries;
  FChart         : TChart;
  FJPEG          : TJPEGImage;
  Bitmap         : TBitmap;
  Rect           : TRect;
  i              : Integer;
begin
{ This is the function the actually creates the TChart on the fly and sends
  back a MemoryStream (containing a JPEG image
  You need to add the units: JPEG, Chart, Series, Graphics, Controls, TeEngine
  to the uses clause in the implementation section.
}
  FChart := TChart.Create(nil);
  FJPEG := TJPEGImage.Create;
  Bitmap := nil;
  try
    { Initialize Chart Properties }
    FChart.Color := clWhite;
    FChart.BevelOuter := bvNone;
    FChart.Legend.Visible := False;
    { Define the Size of the Chart Image }
    Rect.Left := 0;
    Rect.Top := 0;
    Rect.Right := 250;
    Rect.Bottom := 180;
    { Draw the Chart }
    HorizBarSeries := THorizBarSeries.Create(FChart);
    HorizBarSeries.BarStyle := bsRectGradient;
    HorizBarSeries.ParentChart := FChart;
    HorizBarSeries.ShowInLegend := False;
    HorizBarSeries.Marks.Style := smsValue;
    Randomize;
    with FChart do
    begin
      SeriesList.Clear;
      for i := Low(BarTitles) to High(BarTitles) do
      begin
         with HorizBarSeries do
        begin
          Add(BarValues[i], StringReplace(BarTitles[i],'_',' ',[rfReplaceAll]),Random(2147483648));
        end;
      end; { for i := Low(BarTitles) to High(BarTitles) do }
      SeriesList.Add(HorizBarSeries);
      with Title do
      begin
        Font.Size := 10;
        Font.Color := clBlack;
        Text.Clear;
        Text.Add(ChartTitle);
      end;
    end;
    { Generate the Chart as a Bitmap }
    Bitmap := FChart.TeeCreateBitmap(clWhite, Rect);
    FJPEG.Assign(Bitmap);
    FJPEG.SaveToStream(MemStream);
    MemStream.Position := 0;
  finally
    Bitmap.Free;
    FChart.Free;
    FJPEG.Free;
    { No need to Free MemStrm. The ISAPI Framework will take care of that }
  end;
end;