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            "Delphi X-Files" <www.DelphiXFiles.narod.ru"
                        "Затемнение экрана"
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Часто пользователи спрашивают о том, каким образом можно затемнить экран (как при Завершении Работы).

procedure GrayDesktop();
const
  Color1 = clWhite;
  Color2 = clBlack;{}
  {Color1 = $00AAAAAA;
  Color2 = $00555555;{}
var
  DesktopDC, MemDC: HDC;
  NewBitmap, OldBitmap: HBITMAP;
  I, J: Integer;
begin
  DesktopDC := GetDC(0);
  try
    MemDC := CreateCompatibleDC(DesktopDC);
    if MemDC <>0 then
    begin
      NewBitmap := CreateCompatibleBitmap(DesktopDC, 32, 32);
      if NewBitmap <>0 then
      begin
        OldBitmap := SelectObject(MemDC, NewBitmap);
        for I := 0 to 31 do
          for J := 0 to 31 do
            if (I + J) and 1 = 0 then
              SetPixel(MemDC, I, J, Color1)
            else
              SetPixel(MemDC, I, J, Color2);
        { Paint }
        J := 0;
        while J <Screen.Height do
        begin
          I := 0;
          while I <Screen.Width do
          begin
            BitBlt(DesktopDC, I, J, 32, 32, MemDC, 0, 0, SRCAND);
            Inc(I, 32);
          end;
          Inc(J, 32);
        end;
        { Delete objects }
        DeleteObject(NewBitmap);
        SelectObject(MemDC, OldBitmap);
      end;
      DeleteDC(MemDC);
    end;
  finally
    ReleaseDC(0, DesktopDC);
  end;
end;
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