Region vom Bitmap erstellen...

[Progman]

Meinst du sowas?

Delphi-Quellcode:

type
  TRGBArray = array[0..32767] of TRGBTriple;
  PRGBArray = ^TRGBArray;

type
  TfrmMain = class(TForm)
    ...
  private
    { Private-Deklarationen }
    HG: TBitmap;
    FRegion: THandle;
    function CreateRegion(Bmp: TBitmap): THandle;
  public
    ...
  end;

implementation

function TfrmMain.CreateRegion(Bmp: TBitmap): THandle;
var
  X, Y, StartX: Integer;
  Excl: THandle;
  Row: PRGBArray;
  TransparentColor: TRGBTriple;
begin
  Bmp.PixelFormat := pf24Bit;
  Result := CreateRectRGN(0, 0, Bmp.Width, Bmp.Height);
  for Y := 0 to Bmp.Height - 1 do
  begin
    Row := Bmp.Scanline[Y];
    StartX := -1;
    if Y = 0 then
      TransparentColor := Row[0];
    for X := 0 to Bmp.Width - 1 do
    begin
      if (Row[X].rgbtRed = TransparentColor.rgbtRed) and
        (Row[X].rgbtGreen = TransparentColor.rgbtGreen) and
        (Row[X].rgbtBlue = TransparentColor.rgbtBlue) then
      begin
        if StartX = -1 then StartX := X;
      end
      else
      begin
        if StartX > -1 then
        begin
          Excl := CreateRectRGN(StartX, Y, X + 1, Y + 1);
          try
            CombineRGN(Result, Result, Excl, RGN_DIFF);
            StartX := -1;
          finally
            DeleteObject(Excl);
          end;
        end;
      end;
    end;
    if StartX > -1 then
    begin
      Excl := CreateRectRGN(StartX, Y, Bmp.Width, Y + 1);
      try
        CombineRGN(Result, Result, Excl, RGN_DIFF);
      finally
        DeleteObject(Excl);
      end;
    end;
  end;
end;


//Borderstyle muss bsNone sein
procedure TfrmMain.FormCreate(Sender: TObject);
var Bmp: TBitmap;
begin
  HG:=TBitmap.Create;
  HG.LoadFromFile(ResPath+'Monitor.bmp');
  Bmp := TBitmap.Create;
  try
    bmp.Assign(HG);
    Width:=HG.Width;
    ClientHeight:=HG.Height;
    FRegion := CreateRegion(Bmp);
    SetWindowRGN(Handle, FRegion, True);
  finally
    Bmp.Free;
  end;
  ...
end;

procedure TfrmMain.FormDestroy(Sender: TObject);
begin
  DeleteObject(FRegion);
  HG.Free;
end;

procedure TfrmMain.FormPaint(Sender: TObject);
begin
  BitBlt(canvas.handle, 0, 0, Clientwidth, Clientheight,HG.Canvas.handle, 0, 0, SRCCOPY);
end;

Das erzeugt einer Region anhand eines Bitmaps. Das Fenster hat dann die Form des Bitmaps. Als transparent wird die Farbe der Pixels 0,0 festgelegt (glaub ich)