DISPTIF.PAS
{display a tif file, for portfolio, aug 97, uses turbo4.0

A few graphics procedures for the Atari Portfolio in Turbo 4.0
 by G.W.Rutten, 16 aug 1997 Boekel.

 Test on PC if constant portfolio =3D false, and on portfolio if
 constant portfolio =3D true;
}

uses dos;

var F:file;
    var tag,typ,number_of_fields,block,ofset,
    adres,x,y,i,j,start,aantal_blocks:integer;
    fieldbuf:array[0..11] of integer;
    c:char;
    videoadres,byteorder,version:word;
    dummy,width,height,ifdoffset,count,offset:longint;
    data:byte;
    name:string;
    shiftx,shifty:integer;
    dummybuf:array[0..1023] of byte;

const portfolio=3Dtrue;

var regs:registers;
    stop:boolean;

procedure textmode;
begin
  regs.ax:=3D7;
  intr($10,regs);
end;

procedure putpixel(x,y,pixel:integer);
var adres:integer;
begin;
  regs.ax:=3D12*256+pixel;
  regs.dx:=3Dy;
  regs.cx:=3Dx;
  intr($10,regs);
end;

procedure refresh;
begin
  {refresh the pofo lcd screen}
  regs.bx:=3D0;
  regs.ax:=3D$1200;
  if portfolio then intr($61,regs);
end;

procedure hires;
begin
  regs.ax:=3D$0000;
  if portfolio then intr($61,regs);      {initiliaze int 61}
  regs.bx:=3D0;
  regs.ax:=3D$0006;
  intr($10,regs);
  refresh;
end;

procedure clrscr;
var x:integer;
begin
  for x:=3D0 to 1919 do mem[videoadres:x]:=3D0;
  refresh;
end;

procedure randomscr;
var x:integer;
begin
  for x:=3D0 to 1919 do mem[videoadres:x]:=3Drandom($ff);
  refresh;
end;

procedure scrollup;
var i:integer;
begin
  for i:=3D0 to 1889 do mem[videoadres:i]:=3Dmem[videoadres:i+30];
  for i:=3D1890 to 1919 do mem[videoadres:i]:=3D0;
  refresh;
end;

procedure scrolldown;
var i:integer;
begin
  for i:=3D1889 downto 0 do mem[videoadres:i+30]:=3Dmem[videoadres:i];
  for i:=3D0 to 29 do mem[videoadres:i]:=3D0;
  refresh;
end;

procedure scrollleft;
var y,i:integer;
begin
  for y:=3D0 to 63 do
    begin
      for i:=3D0 to 29 do =
mem[videoadres:y*30+i]:=3Dmem[videoadres:Y*30+i+1];
      mem[videoadres:y*30+29]:=3D0;
    end;
  refresh;
end;

procedure scrollright;
var y,i:integer;
begin
  for y:=3D0 to 63 do
  begin
    for i:=3D28 downto 0 do =
mem[videoadres:y*30+i+1]:=3Dmem[videoadres:Y*30+i];
    mem[videoadres:y*30]:=3D0;
  end;
  refresh;
end;


begin
  if portfolio then name:=3D'gemertbw.tif' else =
name:=3D'c:\mydocu~1\wingps~1\gemertbw.tif';

  assign(f,name);
  reset(f,1);

  blockread(f,byteorder,2);
  blockread(f,version,2);
  blockread(f,ifdoffset,4);
  seek(f,ifdoffset);
  blockread(f,number_of_fields,2);

  for i:=3D1 to number_of_fields do
  begin
    blockread(f,tag,2);
    blockread(f,typ,2);
    blockread(f,count,4);
    blockread(f,offset,4);
    case tag of
      256:width:=3Doffset;
      257:height:=3Doffset;
      273:start:=3Doffset;
    end; {case}
  end;

  {now the data can be displayed}

  if portfolio then videoadres:=3D$b000 else videoadres:=3D$b800;
  hires;
  shiftx:=3D0;
  shifty:=3D0;
  stop:=3Dfalse;
  seek(f,start);
  blockread(f,adres,4);
  repeat
    seek(f,adres+shiftx+(width div 8)*shifty);
    for y:=3D0 to 63 do
    begin
      for x:=3D0 to 29 do
      begin
        blockread(f,data,1);
        mem[videoadres:y*30+x]:=3Dnot data;
      end;
      blockread(f,dummybuf,(width div 8)-29);       {read not used =
bytes}
    end;
{
    refresh;
    c:=3Dreadkey;
    if ord(c)=3D27 then c:=3Dreadkey;
    case ord(c) of
      75:shiftx:=3Dshiftx-1;
      77:shiftx:=3Dshiftx+1;
      72:shifty:=3Dshifty+8;
      80:shifty:=3Dshifty-8;
      27:stop:=3Dtrue;
    end;
    if shiftx < 0 then shiftx:=3D0;
    if shifty < 0 then shifty:=3D0;
    if shiftx > (width-8) then shiftx:=3Dwidth-8;
    if shifty > (height-8) then shifty:=3Dheight-8;
    shiftx:=3Dshiftx+1;
}
  until stop;
  close(f);
  textmode;
end.