안녕하세요... 아이디 도둑 민성기 입니다.
예전에 나우의 송재훈님이 MDI메인폼에 그림넣는 법을
알려 주신 적 있는데요...
그 소스를 고대로 올려 드립니다. 참고 하세요...
파워러브 델파이 97년 8월호에서 가져 왔구만요... ^^;

unit Unit1;

interface

uses
  SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
  Forms, Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
    FOldDefWndProc : Pointer;
    FNewDefWndProc : Pointer;

    procedure ClientWndProc ( var Msg: TMessage );
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.ClientWndProc;
var
  ClientDC : HDC;
  MemDC    : TBitmap;
  MemDCX   : Integer;
  MemDCY   : Integer;
begin
  case Msg.Msg of
    WM_PAINT : begin
                 ClientDC := GetDC ( ClientHandle );

                 MemDC := TBitmap.Create;
                 MemDC.LoadFromFile ( 'C:\ATHENA.BMP' );
                 MemDCX := 0;
                 MemDCY := 0;
                 repeat
                  repeat
                    BitBlt ( ClientDC, MemDCX, MemDCY, MemDC.Width,
                               MemDC.Height, MemDC.Canvas.Handle,                  
                               0, 0, SRCCOPY );
                    Inc ( MemDCX, MemDC.Width );

                  until MemDCX >= ClientWidth;
                  MemDCX := 0;
                  Inc ( MemDCY, MemDC.Height );
                 until MemDCY >= ClientHeight;
                 ReleaseDC ( ClientHandle, ClientDC );
                 MemDC.Free;
               end;
  end;
  with Msg do
    Result := CallWindowProc ( FOldDefWndProc, ClientHandle,
                                    Msg, wParam, lParam );

end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  FNewDefWndProc := MakeObjectInstance ( ClientWndProc );
  FOldDefWndProc := Pointer(SetWindowLong(ClientHandle,
                                               GWL_WNDPROC,
                                               LongInt ( FNewDefWndProc ) ) );
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin

SetWindowLong (ClientHandle, GWL_WNDPROC, LongInt  FOldDefWndProc));

  FreeObjectInstance ( FNewDefWndProc );
end;

end.