Code:

unit Unit1;

interface

uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

Dialogs, ExtCtrls, StdCtrls, Buttons;

type

TForm1 = class(TForm)

   Image3: TImage;

   Image2: TImage;

   Image1: TImage;

   procedure FormCreate(Sender: TObject);

protected

procedure ImagesWindowRgn;

public

end;

var

Form1: TForm1;

implementation

uses Types;

{$R *.dfm}

procedure TForm1.ImagesWindowRgn;

var

FullRgn, Rgn: THandle;

ClientX, ClientY, i , k: integer;

x, y, firstx, cl : integer;

last : boolean;

temprgn : hrgn;

Begin

k:=0;

ClientX := (Width  - ClientWidth) div 2;

ClientY :=  Height - ClientHeight  -  ClientX;

FullRgn:=CreateRectRgn(0,0,Width,Height);

Rgn:=CreateRectRgn(ClientX,ClientY,ClientX+ClientWidth,ClientY+ClientHeight);

CombineRgn(FullRgn,FullRgn,Rgn,RGN_DIFF);

for i:=0 to ControlCount-1 do

with Controls[i] do

begin

//      Rgn:=CreateRectRgn(ClientX+Left,ClientY+Top,ClientX+Left+Width,ClientY+Top+Height);

//      CombineRgn(FullRgn,FullRgn,Rgn,RGN_OR);

//***************************************************************************************

     if (TImage(Controls[i]).Picture) <> nil then

     with TImage(Controls[i]) do

     Begin

     if Transparent then

     cl := Picture.Bitmap.Canvas.Pixels [0, 0];

     for y:=0 to Picture.Bitmap.height-1 do

      begin

        firstx:=0; last:=false;

         for x:=0 to Picture.Bitmap.width-1 do

          if(abs( Picture.Bitmap.canvas.pixels[x,y] - cl)>0) and (x<>pred( Picture.Bitmap.width))  then

           begin

             if not last then

               begin

                 last:=true;

                 if Transparent then

                 firstx:=x;

               end;

           end else

           if last then

           begin

             last:=false;

             temprgn:=CreateRectRgn( firstx+left,

                                     y+Top,

                                     left+x,

                                     Top+y+1);

//              temprgn:=createrectrgn(firstx,y,x,y+1);

             CombineRgn(FullRgn,FullRgn,temprgn,RGN_or);

             deleteobject(temprgn);

           end;

      end;

     end;

//***************************************************************************************

end;

SetWindowRgn(Handle,FullRgn,true);

end;

procedure TForm1.FormCreate(Sender: TObject);

begin

HorzScrollbar.Visible := false;

VertScrollbar.Visible := false;

BorderStyle:=bsNone;

ImagesWindowRgn;

end;

end.