Alpha-Blending auf beliebigem Hintergrund

[sniper_w]

Delphi-Quellcode:

procedure GetImage(x, y, width, height:Integer;var MyImage:TBitmap);
  var DeskDC:THandle;
begin
  if not Assigned(MyImage) then
  begin
    MyImage := TBitmap.Create();
  end;
  MyImage.Width := width;
  MyImage.Height := height;
  MyImage.PixelFormat := pf32bit;
  DeskDC := GetDC( GetDesktopWindow() );
  BitBlt( MyImage.Canvas.Handle, 0,0, width, height, DeskDC, x, y, SRCCOPY);
  ReleaseDC( GetDesktopWindow(), DeskDC );
end;

procedure TForm1.Button1Click(Sender: TObject);
  var temp:TBitmap;
begin
  temp := nil;
  GetImage(10,10,200,100,temp);
  Canvas.Draw(50,50,temp);
  FreeAndNil(temp);
end;