🚀 go-pugleaf

In article <1902@fcs280s.ncifcrf.gov> toms@fcs260c2.ncifcrf.gov (Tom 
Schneider) writes:
> I would like to make some characters of a precise size, for example,
> 10.3 cm high.  I am being thwarted because fonts are not consistent 
> between PostScript printers.  That is, if I draw a character to fit just
> outside a rectangle and show it on NeWS, then the same program makes the
> character INSIDE the rectangle when printed to a LaserWriter ntxII.
> 
> This Is Frustrating! :-(
> 
> Is there any way to rescale the font so that it is the same size on all
> printers?  For example, is there an easy way to get a hold of the exact
> character size so as to correct for these non-standard effects?  (And I
> thought PostScript was supposed to be a standard language, hruummph!
> Aren't there people working on making this more standard?)
> 
The problem facing you is that, while the PostScript language is more or 
less standard, the font shapes depend on the designer, type vendor, or 
language implementation.  The fonts used in NeWS are not exactly the same 
as those from Adobe, which are not the same as those from Bitstream, which 
are not the same as the original lead type, etc.  (This is an 
industry-wide issue.)  One way to compensate for this in PostScript is to 
use the charpath and pathbbox operators and scale appropriately.

This routine takes a fontname, a string, and a height in points, and 
scales the font so that every character in the string prints at the same 
height.  It also adjusts the currentpoint so that every character rests on 
the baseline (try it with "g"!).  The results are pretty hideous for 
anything except what you are trying to do:

    /heightshow {             % fontname string height  heightshow  -
      /ht exch def
      /str exch def
      /fnt exch def
      /s1 1 string def
      str {                   % for each char in the string
        s1 0 3 -1 roll put    % convert char to string
        gsave  
          newpath 
          0 0 moveto
          fnt findfont setfont
          s1 true charpath 
          flattenpath 
          pathbbox            % compute bounding box of 1 pt. char
          2 index sub         % ury - lly = char height
          ht exch div         % scale for char to match req. height 
          /scalefactor exch def
          pop                 % don't need urx
          scalefactor mul     % adjust lly so char sits on baseline
          /yadjust exch def 
          pop                 % don't need llx
        grestore
        fnt findfont scalefactor scalefont setfont
        0 yadjust neg rmoveto
        s1 show
        0 yadjust rmoveto
      } forall
    } bind def

    /ptspercm 72.0 2.54 div def
    36 36 moveto
    /Helvetica-Bold (C) 10.3 ptspercm mul heightshow
    showpage

> If I could build a font from scratch, then it would solve another problem 
> I have, which is that in the font I prefer (Helvetica-Bold), some of the
> characters reach above and below the line they rest on.  That is, relative
> to an A, the letters C and G extend above and below the lines.  This is a
> royal pain for what I'm doing.  So far, I have had to empirically figure
> out scale factors to correct for this.  It would be nice to have a clean
> solution, like a font which I have complete control over.
> 
Having rounded characters extend above and below the lines may be a royal 
pain for what you are doing, but it is essential for legible typography.  
(To see this, print something like "CHEOPS" with the heightshow routine... 
the rounded characters will appear smaller than the non-rounded 
characters!)

--Kevin Andresen [kevina@apple.com]
"Technically, Sen. Helms is a member of the arachnid family."