// Пример рисует две горизонтальные линии на экране используя TDesktopCanvas.
program TrinitronTraining;

uses
  Messages, Windows, Graphics, Forms;

type
  TDesktopCanvas = class(TCanvas)
  private
    DC : hDC;
    function GetWidth:Integer;
    function GetHeight:Integer;
  public
    constructor Create;
    destructor Destroy; override;
  published
    property Width: Integer read GetWidth;
    property Height: Integer read GetHeight;
end;

{ Объект TDesktopCanvas }
function TDesktopCanvas.GetWidth:Integer;
begin
  Result:=GetDeviceCaps(Handle,HORZRES);
end;

function TDesktopCanvas.GetHeight:Integer;
begin
  Result:=GetDeviceCaps(Handle,VERTRES);
end;

constructor TDesktopCanvas.Create;
begin
  inherited Create;
  DC := GetDC(0);
  Handle := DC;
end;

destructor TDesktopCanvas.Destroy;
begin
  Handle := 0;
  ReleaseDC(0, DC);
  inherited Destroy;
end;


const
  YCount = 2;

var
  desktop : TDesktopCanvas;
  dx,dy : Integer;
  i : Integer;
  F : array[1..YCount] of TForm;

function CreateLine(Y : Integer) : TForm;
begin
  Result := TForm.Create(Application);
  with Result do begin
    Left := 0;
    Top := y;
    Width := dx;
    Height := 1;
    BorderStyle := bsNone;
    FormStyle := fsStayOnTop;
    Visible := True;
  end;
end;

procedure ProcessMessage;
var
  Msg : TMsg;
begin
  if PeekMessage(Msg, 0, 0, 0, PM_REMOVE) then
    if Msg.message = WM_QUIT then
      Application.Terminate;
end;

begin
  desktop := TDesktopCanvas.Create;
  try
    dx := desktop.Width;
    dy := desktop.Height div (YCount+1);
  finally
    desktop.free;
  end;
  for i:=1 to YCount do
    F[i]:=CreateLine(i*dy);
  Application.NormalizeTopMosts;
  ShowWindow(Application.Handle, SW_Hide);

  for i:=1 to YCount do
    SetWindowPos(F[i].Handle, HWND_TOPMOST, 0,0,0,0, SWP_NOACTIVATE+SWP_NOMOVE+SWP_NOSIZE);

  {
  следующие строки используются для того, чтобы не останавливаться
  repeat
  ProcessMessage;
  until false;
  }
  Sleep(15000);

  for i:=1 to YCount do
    F[i].Free;
end.