Steema Central

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Series1.Marks.ArrowLength := -25;

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procedure CenterMarks(barSeries: TBarSeries);
var i : Integer;
  yPos,yPos1,yPos2: Integer;
  xPos: Integer;
  MarkPos: TSeriesMarkPosition;
begin
  MarkPos := TSeriesMarkPosition.Create;
  for i := 0 to barSeries.Count - 1 do
  begin
    // just an example, you can do further customization here
    MarkPos.Width := barSeries.BarWidth - 10;
    MarkPos.Height := 16;

    yPos1 := barSeries.CalcYPos(i); // get y screen pixel coordinate
    if barSeries.UseYOrigin then yPos2 := barSeries.CalcYPosValue(0.0)
    else yPos2 := barSeries.GetHorizAxis.PosAxis;
    yPos := (YPos1+YPos2-MarkPos.Height) div 2;
    xPos := barSeries.CalcXPos(i);

    MarkPos.Custom := True;
    MarkPos.LeftTop.X := xPos;
    MarkPos.LeftTop.Y := yPos;

    barSeries.Marks.Positions[i] := MarkPos;
  end;
  MarkPos.Free;
  barSeries.Repaint;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Series1.Marks.Arrow.Visible := False;
  Series1.Marks.Visible := True;
  Series1.Add(5);
  Series1.Add(11);
  Series1.Add(-3);
  Series1.Add(2.5);
end;

procedure TForm1.Series1BeforeDrawValues(Sender: TObject);
begin
  CenterMarks(Sender as TBarSeries);
end;

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procedure TForm1.LastSeriesGetMarkText(Sender: TChartSeries;
      ValueIndex: Integer; var MarkText: String);
var i:integer;
    tmp:double;
begin
     //sweeps through all values and calculates total
     tmp:=0;
     for i:=0 to Chart1.SeriesList.Count-1 do
     if Chart1.Series[i].Active then
      tmp:=tmp+Chart1.Series[i].YValue[ValueIndex]; //sum YValues
      MarkText:=FloatToStr(tmp); //write a new MarkText

end;


procedure TForm1.FormCreate(Sender: TObject);
var i:Integer;
begin
     for i:=0 to Chart1.SeriesList.Count-1 do
     with Chart1.Series[i] do
     begin
       FillSampleValues(10);
       Marks.Visible:=false; //we don't want marks for series
     end;
     with Chart1.Series[i-1] do
     begin
      OnGetMarkText:=LastSeriesGetMarkText; //assign OnGetMarkText event to last series
      Marks.Visible:=true; //on the other hand, we want a mark for last series
     end;

end;

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procedure TForm1.PositionChartMarks(BarSeries: TBarSeries);
var
  i: integer;
  YPos: integer;
  BarTop: integer;
  BarBottom: integer;
  XPos: integer;
  MarkPos: TSeriesMarkPosition;
begin
  MarkPos := TSeriesMarkPosition.Create;
  try
    for i := 0 to BarSeries.Count - 1 do begin
      // just an example, you can do further customization here
      MarkPos.Width := BarSeries.BarWidth;
      MarkPos.Height := 16;

      BarTop := BarSeries.CalcYPos(i); // get y screen pixel coordinate
      BarBottom := BarSeries.CalcYPosValue(BarSeries.PointOrigin(i,false));

      YPos := (BarTop + BarBottom - MarkPos.Height) div 2;
      // Make sure that the value isn't painted below the X Axis
      if YPos > (BarSeries.GetHorizAxis.PosAxis - (MarkPos.Height)) then begin
        YPos := BarSeries.GetHorizAxis.PosAxis - (MarkPos.Height);
      end;
      XPos := BarSeries.CalcXPos(i);

      MarkPos.Custom := True;
      MarkPos.LeftTop.X := XPos;
      MarkPos.LeftTop.Y := YPos;

      BarSeries.Marks.Positions[i] := MarkPos;
    end;
  finally
    MarkPos.Free;
  end;
  BarSeries.Repaint;
end;


procedure TForm1.Series1BeforeDrawValues(Sender: TObject);
begin
  PositionChartMarks(Sender as TBarSeries);
end;