{ This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
}

unit Screen;

{ Descripcion:
    Objeto para manejar paneles (ventanas 2 dimensionales) en la pantalla
    Inicializar el objeto con:
    	<pan>.Initialize(tX1, tY1, tX2, tY2, tFC, tBC: integer)
    	    donde tX1, tY1 son las coordenadas de la esquina izq superior
    	          tX2, tY2 son las coordenadas de la esquina der inferior
    	          tFC es el color del texto
    	          tBC es el color para el fondo
    Métodos disponibles:
    	<pan>.ClearScreen borra el panel completamente
    	<pan>.OutText(X, Y: integer; S: string) muestra S en X, Y
    	<pan>.InsertLine(Y: integer; S: string) inserta S en la linea Y
    	<pan>.DeleteLine(Y: integer) borra la linea Y
    	<pan>.WriteLine(S: string) agrega S al final del panel
    	<pan>.GetCommand(S: string) escribe S como prompt, y devuelve
    	    el comando tipeado por el usuario.
    	<pan>.FlashMessage(Y: integer; S: string; T: integer) muestra el
    	    mensaje S en la linea Y, por un maximo de T milisegundos.
    	<pan>.Height devuelve la altura del panel en lineas.
}

interface

type
  tPanel = object
    X1, X2, Y1, Y2, FC, BC: integer;
    Line1, OldMin, OldMax: word;
    OldCol: byte;

    procedure Initialize(tX1, tY1, tX2, tY2, tFC, tBC: integer);
    procedure ClearScreen;
    procedure OutText(X, Y: integer; S: string);
    procedure InsertLine(Y: integer; S: string);
    procedure DeleteLine(Y: integer);
    procedure WriteLine(S: string);
    function  GetCommand(S: string): string;
    procedure FlashMessage(Y: integer; S: string; T: integer);
    function  Height: integer;

    procedure EnterWindow;
    procedure ExitWindow;
  end;

implementation

uses CRT, Strings;

var
  RealScr: array [1..25, 1..80] of word absolute $b800:0;

procedure tPanel.EnterWindow;
begin
  OldMin := WindMin;
  OldMax := WindMax;
  OldCol := TextAttr;
  Window(X1, Y1, X2, Y2);
  TextColor(FC);
  TextBackground(BC);
end;

procedure tPanel.ExitWindow;
begin
  Window(lo(OldMin)+1, hi(OldMin)+1,
         lo(OldMax)+1, hi(OldMax)+1);
  TextAttr := OldCol;
end;

procedure tPanel.Initialize(tX1, tY1, tX2, tY2, tFC, tBC: integer);
begin
  X1 := tX1; X2 := tX2;
  Y1 := tY1; Y2 := tY2;
  FC := tFC; BC := tBC;
  EnterWindow;
  clrscr;
  ExitWindow;
end;

procedure tPanel.ClearScreen;
begin
  EnterWindow;
  ClrScr;
  ExitWindow;
end;

procedure tPanel.OutText(X, Y: integer; S: string);
begin
  EnterWindow;
  gotoXY(X, Y);
  clreol;
  write(S);
  ExitWindow;
end;

procedure tPanel.InsertLine(Y: integer; S: string);
begin
  EnterWindow;
  gotoXY(1, Y);
  InsLine;
  write(S);
  ExitWindow;
end;

procedure tPanel.DeleteLine(Y: integer);
begin
  EnterWindow;
  gotoXY(1, Y);
  DelLine;
  ExitWindow;
end;

procedure tPanel.WriteLine(S: string);
begin
  EnterWindow;
  gotoXY(1, 1);
  DelLine;
  gotoXY(1, Y2-Y1+1);
  write(S);
  ExitWindow;
end;

procedure tPanel.FlashMessage(Y: integer; S: string; T: integer);
var
  pSave: pointer;
  Del, Len: integer;
begin
  EnterWindow;
  Len := X2 - X1 + 1;
  getmem(pSave, 2*Len);
  move(RealScr[Y+Y1-1, X1], pSave^, 2*Len);
  gotoXY(1, Y); clreol;
  write(' ', S);
  Del := 0;
  while not KeyPressed and (Del < T) do begin
    inc(Del); delay(1);
  end;
  move(pSave^, RealScr[Y+Y1-1, X1], 2*Len);
  freemem(pSave, 2*Len);
  ExitWindow;
end;

function tPanel.GetCommand(S: string): string;
var
  Cmd: string;
  Ch: char;
begin
  EnterWindow;
  gotoXY(1, 1); DelLine;
  gotoXY(1, Height); write(S);
  Cmd := '';
  repeat
    Ch := GetKey;
    case Ch of
      ' '..'~': Cmd := Cmd + Ch;
      BS      : if Cmd <> '' then
                  Cmd := copy(Cmd, 1, length(Cmd)-1);
      F10,
      AltX    : begin Cmd := 'X'; Ch := CR; end;
    end;
    gotoXY(length(S)+1, Height); clreol;
    write(Cmd);
  until Ch = CR;
  ExitWindow;
  GetCommand := Cmd;
end;

function tPanel.Height: integer;
begin
  Height := Y2 - Y1 + 1;
end;

begin
end.