Steema Central

Code: Select all

var
  Form1: TForm1;
  X0, X1, Y0, Y1: Integer;
implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
    X0 := -1;
    Y0 := -1;

    Chart1.Zoom.Allow := false;
    Chart1.View3D := false;
end;

procedure TForm1.Chart1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
  X1 := X;
  Y1 := Y;

  If (X0 <> -1) And (Y0 <> -1) Then
  begin
    Chart1.Canvas.Brush.Style := bsClear;
    Chart1.Canvas.Pen.Color := clBlack;
    Chart1.Canvas.Rectangle(X0, Y0, X1, Y1);
    Chart1.Draw;
  End;
end;

procedure TForm1.Chart1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  X0 := X;
  Y0 := Y;
end;

procedure TForm1.Chart1MouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
var RectSeries: TChartShape;
begin
  If (X0 <> -1) And (Y0 <> -1) Then
  begin
    RectSeries := TChartShape.Create(Self);
    Chart1.AddSeries(RectSeries);

    with (Chart1.Axes) do
    begin
      RectSeries.Style := chasRectangle;
      RectSeries.X0 := Bottom.CalcPosPoint(X0);
      RectSeries.Y0 := Left.CalcPosPoint(Y0);
      RectSeries.X1 := Bottom.CalcPosPoint(X1);
      RectSeries.Y1 := Left.CalcPosPoint(Y1);
    end;
  End;

  X0 := -1;
  Y0 := -1;
end;