DVItype change file for Tops-20
Copyright (C) 1983 by David Fuchs.  All rights are reserved.

@x Tell WEAVE to print only the changes:
\pageno=\contentspagenumber \advance\pageno by 1
@y
\pageno=\contentspagenumber \advance\pageno by 1
\let\maybe=\iffalse
\def\title{DVI$\,$\lowercase{type} changes for Tops-20}
@z

@x TOPS-20's banner:
@d banner=='This is DVItype, Version 2.9' {printed when the program starts}
@y

Version 2.9a adds output of page coordinates in pixels, |hh_page|
measured from the left edge of the output page, |vv_up| measured from
the bottom edge, and |vv_down| measured from the top edge.  Page size is
assumed to be 8.5in by 11in, with the TeX origin placed one inch over
and down from the upper-left corner, as decreed by the Stanford TeX
Project.  In addition, commands which update the current |h| or |v|
positions now display the page coordinates before as well as after the
operation.  This additional output should simplify checking of DVI
driver programs for actual output devices.

@d banner=='This is DVItype, Tops-20 Version 2.9a with (hhpage,vvpage) output'
@z

@x Identify input vs. output files so version numbers are properly handled:
@p program DVI_type(@!dvi_file,@!output);
@y
@p program DVI_type(@!dvi_file:-,@!output:+,TTY:/);
@z

@x Open dvi_file in binary mode:
begin reset(dvi_file);
@y
begin reset(dvi_file,'','/B:8');
@z

@x Open tfm_file in binary mode:
begin reset(tfm_file,cur_name);
@y
begin reset(tfm_file,cur_name,'/B:8');
@z

@x
@!resolution:real; {pixels per inch}
@y
@!resolution:real; {pixels per inch}
@!hh_max:integer; { page width in pixels }
@!hh_offset:integer; { left margin offset }
@!hh_page:integer; { page coordinate in pixels }
@!vv_down:integer; { page coordinate in pixels }
@!vv_max:integer; { page height in pixels }
@!vv_offset:integer; { top margin in pixels }
@!vv_up:integer; { page coordinate in pixels }
@z

@x Hardwire term_in and term_out to TTY:
and |term_out| for terminal output.
@^system dependencies@>

@<Glob...@>=
@!buffer:array[0..terminal_line_length] of ASCII_code;
@!term_in:text_file; {the terminal, considered as an input file}
@!term_out:text_file; {the terminal, considered as an output file}
@y
and |term_out| for terminal output.
@^system dependencies@>

@d term_in==TTY {the terminal, considered as an input file}
@d term_out==TTY {the terminal, considered as an output file}

@<Glob...@>=
@!buffer:array[0..terminal_line_length] of ASCII_code;
@z

@x Update_terminal does nothing:
@d update_terminal == break(term_out) {empty the terminal output buffer}
@y
@d update_terminal == do_nothing {empty the terminal output buffer}
@z

@x
begin update_terminal; reset(term_in);
@y
begin update_terminal;
@z

@x
begin rewrite(term_out); {prepare the terminal for output}
@y
begin {no need to prepare the terminal for output}
@z

@x
print_ln('  Resolution = ',resolution:12:8,' pixels per inch');
@y
print_ln('  Resolution = ',resolution:12:8,' pixels per inch');
hh_max:=round(8.5 * resolution); { page width in pixels }
vv_max:=round(11.0 * resolution); { page height in pixels }
hh_offset:=round(1.0 * resolution); { left margin 1.0in in }
vv_offset:=round(1.0 * resolution);	{ top margin 1.0in down }
print_ln('  Page size  = ',hh_max:1,'H x ',vv_max:1,'V pixels');
print_ln('  TeX top left page corner is ',hh_offset:1,' pixels over and ',
    vv_offset:1,' pixels down on physical page');
@z

@x
hhh:=pixel_round(h+q);
@y
if showing then
 begin
  hhh:=pixel_round(h);
  hh_page:=hh_offset + hhh;
  print_ln(' ':6,'old_hh:=',hhh:1,', old_hh_page:=',hh_page:1,',');
  print(' ':5);
 end;
hhh:=pixel_round(h+q);
@z

@x
  print(q:1,'=',h+q:1,', hh:=',hh:1);
@y
  print(q:1,'=',h+q:1,', hh:=',hh:1);
  hh_page:=hh_offset + hh;
  print(', hh_page:=',hh_page:1);
@z

@x
vvv:=pixel_round(v+p);
@y
if showing then
  begin
    vvv:=pixel_round(v);
    vv_down:=vvv + vv_offset;
    vv_up:=vv_max - vv_down;
    print_ln(' old_vv:=',vvv:1,', old_vv_up:=',vv_up:1,
      ', old_vv_down:=',vv_down:1,',');
    print(' ':5);
  end;
vvv:=pixel_round(v+p);
@z

@x
  print(p:1,'=',v+p:1,', vv:=',vv:1);
@y
  print(p:1,'=',v+p:1,', vv:=',vv:1);
  vv_down:=vv + vv_offset;
  vv_up:=vv_max - vv_down;
  print(', vv_up:=',vv_up:1,', vv_down:=',vv_down:1);
@z

@x
  print('level ',ss:1,':(h=',h:1,',v=',v:1,
    ',w=',w:1,',x=',x:1,',y=',y:1,',z=',z:1,
    ',hh=',hh:1,',vv=',vv:1,')');
@y
  hh_page:=hh_offset + hh;
  vv_down:=vv + vv_offset;
  vv_up:=vv_max - vv_down;
  print_ln('level ',ss:1,':(h=',h:1,',v=',v:1,
    ',w=',w:1,',x=',x:1,',y=',y:1,',z=',z:1,
    ',hh=',hh:1,',vv=',vv:1,',');
  print(' ':6,'hh_page=',hh_page:1,
    ',vv_up=',vv_up:1,',vv_down=',vv_down:1,')');
@z