unit Unit1;    interface    uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, ExtCtrls;    type
  TForm1 = class(TForm)
    Image1: TImage;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;    var
  Form1: TForm1;    implementation    {$R *.DFM}    procedure TForm1.Button1Click(Sender: TObject);
begin
  Image1.Picture:=nil ;
end;    procedure TForm1.Button2Click(Sender: TObject);
var
  dc : HDC ;
begin
  dc:=Image1.Canvas.Handle ;
  BitBlt(dc,0,0,image1.Width,image1.height,dc,0,0,SRCERASE) ;
  image1.Refresh ;
end;    procedure TForm1.Button3Click(Sender: TObject);
var
  dc : HDC ;
begin
  dc:=Image1.Canvas.Handle ;
  BitBlt(dc,0,0,image1.Width,image1.height,dc,0,0,WHITENESS) ;
  image1.Refresh ;
end;    end.