Subject: Hershey fonts

This submission is being sent in response to a question in texhax [#70].
I (jok@gpu.utcs.toronto.edu) am posting this submission for my father, Oliver.
Consequently, everything after this paragraph is written by him.  I will
accept any responses and forward them to him.  His interest in TeX
revolves around multi-lingual (hobby) desktop publishing.

Hershey fonts for the IBM PC are available from SoftCraft, Inc., and from
Austin Code Works. The SoftCraft set consists of four separate databases:
  HERSHEY.CHR  1594 characters
  ORIENT.CHR    758 char.
  PERSIAN.CHR   135 char.
  HEBREW.CHR     49 char.
The HERSHEY.CHR database includes, besides several Roman typefaces, Greek,
Russian, German Fraktur, and a variety of graphic symbols; the ORIENT.CHR
database has hiragana, katakana, and 623 kanji characters.

The format of the SoftCraft Hershey databases is given in their "Font Editing:
EFONT/CFONT User's Manual" on p. A5-2. Using this description, I wrote the
following Turbo Pascal 4.0 program to generate METAFONT source code from the
Hershey plotter directives:

HERSHEY.PAS
-----------
{$R-} {Range checking off}
{$B-} {Short-circuit Boolean evaluation}
{$S-} {Stack checking off}
{$I+} {I/O checking on}
{$N-} {Numeric coprocessor absent}
{$M 65500, 16384, 655360} {Turbo 3 default stack and heap}

program Hershey; {generates METAFONT source code from a Hershey character
  database in SoftCraft format}
const
  NMax = 157; {maximum number of plotter pen movement commands for one
    character in the databases}
  PenUp = $4000;
  EndOfChar = 0;
var
  H : file of integer; {Hershey database input}
  Log : text; {METAFONT source output}
  Code, Depth, EndChar, Height, I, J, K, N, StartChar, Width, XMax, XMin, Y0,
    YMax, YMin : integer;
  XY : array[0..NMax] of integer; {(x, y) coordinates}
  Z : array[1..NMax] of byte; {METAFONT variables}
  Database : string[7]; {database filename without extension}

procedure ReadH; {reads a plotter directive from the input file}
begin
  if Eof(H) then
  begin
    Writeln('End of file at char = ', Code);
    Close(H);
    Close(Log);
    Halt;
  end;
  Inc(N);
  Read(H, XY[N]);
end; {ReadH}

begin
  if ParamCount <> 3 then
  begin
    Writeln('Usage: HERSHEY database start end');
    Halt;
  end;
  Database := ParamStr(1);
  for Code := 1 to 7 do
    Database[Code] := UpCase(Database[Code]);
  Val(ParamStr(2), StartChar, Code);
  if Code <> 0 then
  begin
    Writeln('Starting character not an integer');
    Halt;
  end;
  Val(ParamStr(3), EndChar, Code);
  if Code <> 0 then
  begin
    Writeln('Ending character not an integer');
    Halt;
  end;
  Assign(H, Database + '.CHR');
  Reset(H);
  Assign(Log, Database + '.LOG');
  Rewrite(Log);
  Writeln(Log, '% ', Database + '.CHR  ', StartChar, ' to ', EndChar);
  for Code := 0 to StartChar do
  begin
    N := -1;
    repeat
      ReadH;
    until XY[N] = EndOfChar;
  end; {skip forward to specified start character}
  Z[1] := 1;
  for Code := StartChar to EndChar do
  begin
    Writeln(Log);
    Writeln(Log, 'cmchar "', Database, ' ', Code, '";');
    N := -1;
    ReadH; {the width bytes}
    XMin := Lo(XY[0]); {minimum x coordinate}
    XMax := Hi(XY[0]); {maximum x coordinate}
    Width := XMax - XMin; {width of character}
    Y0 := 73; {default y bias}
    if Database = 'HERSHEY' then
      case Code of
        0..88: Y0 := 68;
        397..672: Y0 := 70;
      end;
    {Find minimum and maximum y values.}
    YMax := 0;
    YMin := 256;
    repeat
      ReadH;
      if (XY[N] <> PenUp) and (XY[N] <> EndOfChar) then
      begin
        if Hi(XY[N]) > YMax then
          YMax := Hi(XY[N]);
        if Hi(XY[N]) < YMin then
          YMin := Hi(XY[N]);
      end; {if a real coordinate}
    until XY[N] = EndOfChar;
    Height := Y0 - YMin; 
    if YMax > Y0 then
      Depth := YMax - Y0
    else
      Depth := 0;
    Writeln(Log, 'beginchar(', Code mod 128, ', ', Width, 'u#, ', Height,
      'u#, ', Depth, 'u#);');
    Writeln(Log, 'adjust_fit(0, 0);');
    Writeln(Log, 'pickup plotter_pen;');
    for I := 2 to Pred(N) do
    begin {enumerate unique coordinates}
      Z[I] := 0;
      if XY[I] <> PenUp then
      begin
        for J := Pred(I) downto 1 do
          if XY[I] = XY[J] then
            Z[I] := J;
        if Z[I] = 0 then
          Z[I] := I;
      end;
    end;
    for I := 1 to Pred(N) do
      if Z[I] = I then
    Writeln(Log, 'z', I, ' = (', Lo(XY[I]) - XMin, 'u, ', Y0 - Hi(XY[I]),
      'u);');
    I := 0;
    J := 1;
    repeat
      Inc(I);
      if (XY[I] = PenUp) or (XY[I] = EndOfChar) then
      begin
        case I - J of {number of points joined by consecutive line segments}
          0: ;
          1: Writeln(Log, 'drawdot z', Z[J], ';');
          2: if Z[J] = Z[Succ(J)] then
               Writeln(Log, 'drawdot z', Z[J], ';')
             else
               Writeln(Log, 'draw z', Z[J], '--z', Z[Succ(J)], ';');
          else
          begin
            Write(Log, 'draw z', Z[J]);
            for K := Succ(J) to Pred(I) do
              Write(Log, '--z', Z[K]);
            Writeln(Log, ';');
          end; {3 or more}
        end; {case}
        J := Succ(I);
      end; {if a real coordinate}
    until I = N;
    Writeln(Log, 'endchar;');
  end; {specified range of characters}
  Close(H);
  Close(Log);
end.

As a test case I used the DOS command
  hershey orient 0 1
to produce the following output:

ORIENT.LOG
----------
% ORIENT.CHR  0 to 1

cmchar "ORIENT 0";
beginchar(0, 27u#, 12u#, 0u#);
adjust_fit(0, 0);
pickup plotter_pen;
z1 = (3u, 10u);
z2 = (25u, 10u);
z3 = (22u, 12u);
z4 = (20u, 10u);
z7 = (23u, 11u);
draw z1--z2--z3--z4;
draw z4--z7;
endchar;

cmchar "ORIENT 1";
beginchar(1, 27u#, 22u#, 0u#);
adjust_fit(0, 0);
pickup plotter_pen;
z1 = (3u, 20u);
z2 = (25u, 20u);
z3 = (23u, 22u);
z4 = (21u, 20u);
z7 = (24u, 21u);
z9 = (13u, 20u);
z10 = (12u, 13u);
z11 = (11u, 9u);
z12 = (10u, 7u);
z13 = (8u, 4u);
z14 = (6u, 2u);
z15 = (3u, 0u);
z17 = (14u, 20u);
z18 = (13u, 13u);
z19 = (12u, 9u);
z20 = (10u, 5u);
z21 = (8u, 3u);
z22 = (5u, 1u);
z25 = (13u, 14u);
z26 = (21u, 14u);
z28 = (20u, 14u);
z29 = (21u, 15u);
z30 = (23u, 14u);
z31 = (21u, 11u);
z34 = (20u, 7u);
z35 = (19u, 3u);
z36 = (18u, 2u);
z37 = (16u, 1u);
z38 = (13u, 2u);
z40 = (19u, 2u);
z41 = (18u, 1u);
z42 = (17u, 1u);
z44 = (22u, 14u);
z45 = (21u, 7u);
z46 = (20u, 3u);
z47 = (19u, 1u);
z48 = (18u, 0u);
z49 = (17u, 0u);
draw z1--z2--z3--z4;
draw z4--z7;
draw z9--z10--z11--z12--z13--z14--z15;
draw z17--z18--z19--z20--z21--z22--z15;
draw z25--z26;
draw z28--z29--z30--z31;
draw z26--z34--z35--z36--z37--z38;
draw z40--z41--z42;
draw z44--z45--z46--z47--z48--z49--z37;
endchar;


I used the following METAFONT parameter file:

ORIENT.MF
---------
% This is ORIENT.MF in text format, as of May 6, 1988.
% Based on Computer Modern Roman 10 point
if unknown cmbase: input cmbase fi

font_identifier:="ORIENT"; font_size 10pt#;

u#:=20/36pt#;      % unit width
width_adj#:=0pt#;    % width adjustment for certain characters
serif_fit#:=0pt#;    % extra sidebar near lowercase serifs
cap_serif_fit#:=5/36pt#;  % extra sidebar near uppercase serifs
letter_fit#:=0pt#;    % extra space added to all sidebars

body_height#:=270/36pt#;  % height of tallest characters
asc_height#:=250/36pt#;    % height of lowercase ascenders
cap_height#:=246/36pt#;    % height of caps
fig_height#:=232/36pt#;    % height of numerals
x_height#:=155/36pt#;    % height of lowercase without ascenders
math_axis#:=90/36pt#;    % axis of symmetry for math symbols
bar_height#:=87/36pt#;    % height of crossbar in lowercase e
comma_depth#:=70/36pt#;    % depth of comma below baseline
desc_depth#:=70/36pt#;    % depth of lowercase descenders

crisp#:=0pt#;      % diameter of serif corners
tiny#:=8/36pt#;      % diameter of rounded corners
fine#:=7/36pt#;      % diameter of sharply rounded corners
thin_join#:=7/36pt#;    % width of extrafine details
hair#:=9/36pt#;      % lowercase hairline breadth
stem#:=25/36pt#;    % lowercase stem breadth
curve#:=30/36pt#;    % lowercase curve breadth
ess#:=27/36pt#;      % breadth in middle of lowercase s
flare#:=33/36pt#;    % diameter of bulbs or breadth of terminals
dot_size#:=38/36pt#;    % diameter of dots
cap_hair#:=11/36pt#;    % uppercase hairline breadth
cap_stem#:=32/36pt#;    % uppercase stem breadth
cap_curve#:=37/36pt#;    % uppercase curve breadth
cap_ess#:=35/36pt#;    % breadth in middle of uppercase s
rule_thickness#:=.4pt#;    % thickness of lines in math symbols

dish#:=1/36pt#;      % amount erased at top or bottom of serifs
bracket#:=20/36pt#;    % vertical distance from serif base to tangent
jut#:=28/36pt#;      % protrusion of lowercase serifs
cap_jut#:=37/36pt#;    % protrusion of uppercase serifs
beak_jut#:=10/36pt#;    % horizontal protrusion of beak serifs
beak#:=70/36pt#;    % vertical protrusion of beak serifs
vair#:=8/36pt#;      % vertical diameter of hairlines
notch_cut#:=10pt#;    % maximum breadth above or below notches
bar#:=11/36pt#;      % lowercase bar thickness
slab#:=11/36pt#;    % serif and arm thickness
cap_bar#:=11/36pt#;    % uppercase bar thickness
cap_band#:=11/36pt#;    % uppercase thickness above/below lobes
cap_notch_cut#:=10pt#;    % max breadth above/below uppercase notches
serif_drop#:=4/36pt#;    % vertical drop of sloped serifs
stem_corr#:=1/36pt#;    % for small refinements of stem breadth
vair_corr#:=1/36pt#;    % for small refinements of hairline height
apex_corr#:=0pt#;    % extra width at diagonal junctions

o#:=8/36pt#;      % amount of overshoot for curves
apex_o#:=8/36pt#;    % amount of overshoot for diagonal junctions

slant:=0;      % tilt ratio $(\Delta x/\Delta y)$
fudge:=1;      % factor applied to weights of heavy characters
math_spread:=0;      % extra openness of math symbols
superness:=1/sqrt2;    % parameter for superellipses
superpull:=1/6;      % extra openness inside bowls
beak_darkness:=11/30;    % fraction of triangle inside beak serifs
ligs:=2;      % level of ligatures to be included

square_dots:=false;    % should dots be square?
hefty:=false;      % should we try hard not to be overweight?
serifs:=true;      % should serifs and bulbs be attached?
monospace:=false;    % should all characters have the same width?
variant_g:=false;    % should an italic-style g be used?
low_asterisk:=false;    % should the asterisk be centered at the axis?
math_fitting:=false;    % should math-mode spacing be used?

font_coding_scheme:="Hershey ORIENT.CHR";

mode_setup; font_setup;

px#:=rule_thickness#; % horizontal thickness of pen
py#:=.9px#; % vertical pen thickness
define_blacker_pixels(px,py);
pickup pencircle xscaled px yscaled py;
plotter_pen:=savepen;
input \ff\orient.log

font_slant slant; font_x_height x_height#;
if monospace: font_normal_space 9u#; % no stretching or shrinking
 font_quad 18u#;
 font_extra_space 9u#;
else: font_normal_space 6u#+2letter_fit#;
 font_normal_stretch 3u#; font_normal_shrink 2u#;
 font_quad 18u#+4letter_fit#;
 font_extra_space 2u#; fi
bye.

The following sequence of DOS commands
  cd\ff
  hershey orient 0 127
  cd\pcmf
  mf &cm \mode=epson; \mag=magstep 0; input orient /a=99/t
produced ORIENT.240 and ORIENT.TFM in \pcmf for my Epson FX-85 printer,
containing the first 128 characters of ORIENT.CHR.

The characters in the Austin Code Works Hershey database are numbered 1--4326,
with gaps, for a total of 1,377 different alphabetic and graphic characters.
The format is described in Norman M. Wolcott and Joseph Hilsenrath, "A
Contribution to Computer Typesetting Techniques: Tables of Coordinates for
Hershey's Repertory of Occidental Type Fonts and Graphic Symbols," U.S.
Department of Commerce, National Bureau of Standards, April 1976.  In any case,
the following Turbo Pascal 4.0 program converts the ACW Hershey database to
SoftCraft format for further processing.

ACWTOSC.PAS
-----------
{$R-} {Range checking off}
{$B-} {Short-circuit Boolean evaluation}
{$S-} {Stack checking off}
{$I+} {I/O checking on}
{$N-} {No numeric coprocessor}
{$M 65500, 16384, 655360} {Turbo 3 default stack and heap}

program ACWtoSC; {converts the Hershey font tables distributed by The Austin
  Code Works to the format expected by the Cfont program of SoftCraft, Inc.}
const
  PenUp : integer = $4000;
type
  S3 = string[3];
var
  Buf1 : array[1..$2000] of char;
  F1 : text;
  H : file of integer;
  L1 : string[80];
  Fn : array[1..2] of string[64];
  Code, I, L, M, XY : integer;
  X, Y : array[1..144] of integer;
  Eoc : boolean;

function V(S : S3) : integer;
var
  I : integer;
begin
  Val(S, I, Code);
  if (Code <> 0) or ((I < -49) and (I <> -64)) or (I > 49) then
  begin
    Writeln(L1);
    Writeln('Code = ', Code);
    Halt(3);
  end;
  V := I;
end;

begin
  if ParamCount <> 2 then
  begin
    Writeln('Usage: ACWTOSC file1 file2');
    Halt(3);
  end;
  for L := 1 to 2 do
  begin
    Fn[L] := ParamStr(L);
    for M := 1 to Length(Fn[L]) do
      Fn[L][M] := UpCase(Fn[L][M]);
  end;
  Assign(F1, Fn[1]);
  SetTextBuf(F1, Buf1);
  {$I-} Reset(F1); {$I+}
  if IOResult <> 0 then
  begin
    Writeln('Cannot open ', Fn[1]);
    Halt(3);
  end;
  Assign(H, Fn[2]);
  {$I-} Rewrite(H); {$I+}
  if IOResult <> 0 then
  begin
    Writeln('Cannot open ', Fn[2]);
    Close(F1);
    Halt(3);
  end;
  while not Eof(F1) do
  begin
    Readln(F1, L1);
    if Copy(L1, 5, 1) <> ' ' then
    begin
      M := 0;
      Eoc := false;
    end;
    L := 0;
    repeat
      Inc(L);
      Inc(M);
      X[M] := V(Copy(L1, 8 * L + 1, 3));
      Y[M] := V(Copy(L1, 8 * L + 5, 3));
      if (X[M] = -64) and (Y[M] = -64) then
      begin
        Eoc := true;
        Write(H, Code); {two bytes of zeros before each character}
        XY := 256 * (Y[1] + 64) + X[1] + 64; {width of character}
        Write(H, XY);
        for I := 2 to Pred(M) do
          if X[I] = -64 then
            Write(H, PenUp)
          else
          begin
            XY := 256 * (73 + Y[I]) + X[I] + 64;
            Write(H, XY);
          end;
      end;
    until (L = 8) or Eoc;
  end;
  Write(H, Code); {two bytes of zeros at end of file}
  Close(F1);
  Close(H);
end.

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