Project Structure

• Scroll2.dpr
• ScrollF.pas
• ScrollF.dfm

program Scroll2;

uses
  Forms,
  ScrollF in 'ScrollF.pas' {Form2};

{$R *.RES}

begin
  Application.CreateForm(TForm2, Form2);
  Application.Run;
end.

unit ScrollF;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs;

type
  TForm2 = class(TForm)
    procedure FormPaint(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form2: TForm2;

implementation

{$R *.DFM}

procedure TForm2.FormPaint(Sender: TObject);
begin
  SetWindowOrgEx (Canvas.Handle,
    HorzScrollbar.Position,
    VertScrollbar.Position, nil);

  {draw a yellow line}
  Canvas.Pen.Width := 30;
  Canvas.Pen.Color := clYellow;
  Canvas.MoveTo (30, 30);
  Canvas.LineTo (1970, 1970);

  {draw a blue line}
  Canvas.Pen.Color := clNavy;
  Canvas.MoveTo (30, 1970);
  Canvas.LineTo (1970, 30);

  {draw a fuchsia square}
  Canvas.Pen.Color := clFuchsia;
  Canvas.Brush.Style := bsClear;
  Canvas.Rectangle (500, 500,
    1500, 1500);
end;

end.

object Form2: TForm2
  Left = 156
  Top = 112
  Width = 496
  Height = 379
  HorzScrollBar.Range = 2000
  VertScrollBar.Range = 2000
  AutoScroll = False
  Caption = 'Scroll2'
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'MS Sans Serif'
  Font.Style = []
  OldCreateOrder = True
  OnPaint = FormPaint
  PixelsPerInch = 96
  TextHeight = 13
end