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Re: YA Type 3 Hershey font

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luser- -droog wrote:

> I've been playing with the Hershey font data, using the description at:
> http://paulbourke.net/dataformats/hershey/
> but not the files from there.
> All of the .jhf (John(Hunt)'s Hershey Font (Format)) use 12345 as the
> declared character code. Apparently the glyphs in these files are
> arranged positionally to match the printable ascii range, 33-126.
> 
> I got my data file somewhere else (not finding it right now), but it
> appears to be the "older" single-file version, where the declared codes
> have semantic meaning as described in the old Hershey report (not finding
> that either, but if I found a pdf (and I did), it's out there somewhere).
> It appears to be the format Bourke is talking about, too. Char #8 matches
> his example.
> 
> So, this program will read the Hershey font data into a dictionary,
> keyed by the "Occidental" character code.
> 
> That's all I've got for now.
> 
> %!
> /hersheyfile (hershey_occ)(r)file def
> /buf 72 string def
> /charcodes 1 dict def
> 
> /strcat { % a b  .  a+b
>     2 copy length exch length add string % a b new
>     dup 4 3 roll 2 copy 0 exch putinterval % b new' new' a
>     length 4 3 roll putinterval % new''
> } def
> 
> /processline {
>     dup length 0 gt { % non-blank line
>         dup length 5 gt {
>             dup 4 get % line line[4]
>             dup 48 ge
>             exch 57 le  % line '0'<=line[4]<='9'
>             and
>             { % new glyph
>                 dup 1 4 getinterval cvi  % line idx
>                 dup /lastcode exch def
>                 exch 5 1 index length 5 sub getinterval % idx line
>                 charcodes 3 1 roll put
>             }{
>                 charcodes lastcode get exch strcat % append to previous
>                 line charcodes exch lastcode exch put
>             } ifelse
>         }{
>             charcodes lastcode get exch strcat
>             charcodes exch lastcode exch put
>         } ifelse
>     }{ % blank line
>         pop
>     } ifelse
> } def
> 
> {
>     hersheyfile buf readline {
>         processline
>     }{
>         processline
>         exit
>     } ifelse
> } loop
> 
> 
> I just realized there's a better way to
> detect multi-line glyphs. Here I use a heuristic I came up with by
> examining the data. The first column is blank followed by a 4-digit
> character code on a new line. Continuation lines use the first column,
> so anything not starting with space is a continuation. BUT ' R' is a
> valid data point, and it starts with a space, so NOT ALL lines
> beginning with space are in fact new characters. BUT all data points
> will be upper-case characters, biased around ascii 'R'.
> 
> So the heuristic is: a new glyph line must be at least 5 characters
> (longer, really, but at least 5) and contain a digit in position 4
> (0-based). Anything else is a continuation, or nothing if it's a
> totally blank line.
> 
> A better way would be to check count field and read until the glyph
> is complete. This avoids all use of "heuristic", but may actually be
> more complicated to implement. :/
> 
> ...to be continued...

I just found a short description of the file format and a list of 
downloadable fonts at
http://emergent.unpythonic.net/software/hershey

Helge

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YA Type 3 Hershey font luser- -droog <mijoryx@yahoo.com> - 2014-01-06 11:52 -0800
  Re: YA Type 3 Hershey font Helge Blischke <h.blischke@acm.org> - 2014-01-07 19:23 +0100
  Re: YA Type 3 Hershey font Helge Blischke <h.blischke@acm.org> - 2014-01-07 20:40 +0100
    Re: YA Type 3 Hershey font luser- -droog <mijoryx@yahoo.com> - 2014-01-07 22:04 -0800
      Re: YA Type 3 Hershey font luser- -droog <mijoryx@yahoo.com> - 2014-01-07 23:42 -0800
        Re: YA Type 3 Hershey font luser- -droog <mijoryx@yahoo.com> - 2014-01-07 23:53 -0800
          Re: YA Type 3 Hershey font scruss@gmail.com - 2014-04-19 08:47 -0700
            Re: YA Type 3 Hershey font tlvp <mPiOsUcB.EtLlLvEp@att.net> - 2014-04-20 01:12 -0400
              Re: YA Type 3 Hershey font scruss@gmail.com - 2014-04-22 17:29 -0700
                Re: YA Type 3 Hershey font tlvp <mPiOsUcB.EtLlLvEp@att.net> - 2014-04-22 21:42 -0400
        Re: YA Type 3 Hershey font scruss@gmail.com - 2014-04-29 14:56 -0700

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