unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, ToolWin, ComCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    RadioGroup1: TRadioGroup;
    procedure FormCreate(Sender: TObject);
    procedure FormPaint(Sender: TObject);
    procedure RadioGroup1Click(Sender: TObject);
  private
    { Private declarations }
   procedure TransparentBmp(Dc: HDC; Bitmap: HBitmap; xStart: Integer; yStart: Integer; trColor: TColor);
  public
    { Public declarations }
   Bmp: TBitmap;
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}
{$R bmpres.res}
procedure TForm1.FormCreate(Sender: TObject);
begin
 Bmp := TBitmap.Create;
 Bmp.LoadFromResourceName(HInstance,'MAP');
end;

procedure TForm1.FormPaint(Sender: TObject);
begin
 case Radiogroup1.ItemIndex of
 0: Canvas.Draw(10,10,Bmp);
 1: TransparentBmp(Canvas.Handle,Bmp.Handle,10,10,clWhite);
 2:  TransparentBlt(Canvas.Handle,10,10,100,100,Bmp.Canvas.Handle,0,0,bmp.Width,
 bmp.Height,clWhite);
 else Canvas.Draw(10,10,Bmp);
 end;
end;

procedure TForm1.TransparentBmp(Dc: HDC; Bitmap: HBitmap; xStart: Integer;
 yStart: Integer; trColor: TColor);
var bm: Windows.TBitmap;
    hDcTemp: HDC;
    ptSize: TPoint;
    hDcBack, hDcObject, hDcMem, hDcSave: hDc;
    bmAndBack, bmAndObject, bmAndMem, bmSave: HBitmap;
    bmBackOld, bmObjectOld, bmMemOld, bmSaveOld: HBitmap;
    sColor: TColorRef;
begin
 hDcTemp := CreateCompatibleDc(Dc);

 SelectObject(hDcTemp,Bitmap);

 GetObject(Bitmap,Sizeof(bm),@bm);

 ptSize.x := bm.bmWidth;
 ptSize.y := bm.bmHeight;

 //создает временные Dc
 hDcBack := CreateCompatibleDc(Dc);
 hDcObject := CreateCompatibleDc(Dc);
 hDcMem := CreateCompatibleDc(Dc);
 hDcSave := CreateCompatibleDc(Dc);
 //создаем битмапы для каждого DC
 bmAndBack := CreateBitmap(ptSize.x,ptSize.y,1,1,nil);

 bmAndObject := CreateBitmap(ptSize.x,ptSize.y,1,1,nil);

 bmAndMem := CreateCompatibleBitmap(Dc,ptSize.x,ptSize.y);

 bmSave :=  CreateCompatibleBitmap(Dc,ptSize.x,ptSize.y);
 //каждому Dc выбрать витмап для сохранения данных пикселей
 bmBackOld := SelectObject(hDcBack,bmAndBack);

 bmObjectOld := SelectObject(hDcObject,bmAndObject);

 bmMemOld := SelectObject(hDcMem,bmAndMem);

 bmSaveOld := SelectObject(hDcSave,bmSave);

 //установка соответствующего mapping mode
 SetMapMode(hDcTemp,GetMapMode(Dc));
 //сохраняем витмап в темпе, потому что он будет переписан
 BitBlt(HDcSave,0,0,ptSize.x,ptSize.y,HDcTemp,0,0,SRCCOPY);
 //устанавливаем задний план
 sColor := SetBkColor(hDcTemp,trColor);
 //создаем маску
 BitBlt(hDcObject,0,0,ptSize.x,ptSize.y,hDcTemp,0,0,SRCCOPY);
 //устанавливаем задний план обратно в оригинал
 SetBkColor(hDcTemp,sColor);
 //готовим инверсную маску
 BitBlt(hDcBack,0,0,ptSize.x,ptSize.y,hDcObject,0,0,NOTSRCCOPY);
 //копируем задний план основного Dc
 BitBlt(hDcMem,0,0,ptSize.x,ptSize.y,Dc,xStart,yStart,SRCCOPY);
 //
 BitBlt(hDcMem,0,0,ptSize.x,ptSize.y,hDcObject,0,0,SRCAND);
 //
 BitBlt(hDcTemp,0,0,ptSize.x,ptSize.y,hDcBack,0,0,SRCAND);
 //
 BitBlt(hDcMem,0,0,ptSize.x,ptSize.y,hDcTemp,0,0,SRCPAINT);
 //
 BitBlt(Dc,xStart,yStart,ptSize.x,ptSize.y,hDcMem,0,0,SRCCOPY);
 //
 BitBlt(hDcTemp,0,0,ptSize.x,ptSize.y,hDcSave,0,0,SRCCopy);

 DeleteObject(SelectObject(hDcBack,bmBackOld));
 DeleteObject(SelectObject(hDcObject,bmObjectOld));
 DeleteObject(SelectObject(hDcMem,bmMemOld));
 DeleteObject(SelectObject(hDcSave,bmSaveOld));
 DeleteDc(hDcBack);
 DeleteDc(hDcObject);
 DeleteDc(hDcMem);
 DeleteDc(hDcSave);
 DeleteDc(hDcTemp);
end;


procedure TForm1.RadioGroup1Click(Sender: TObject);
begin
 Invalidate;
end;


end.