Postscript bug in /reencode when /UnderlineThickness not present in FontInfo dictionary

[Bill Fenner]

The postscript that a2ps 4.13 generates won't render using Apple's  
postscript interpreter (tested using MacOS 10.3.x or 10.4.x) which is  
used, e.g., if you have a raster-based printer attached to your  
system.  In response to my bug report, an Apple engineer pointed out  
that it appears to be a problem with the postscript that a2ps  
generates - Apple's text below:

The code in the /reencode procedure currently reads:
     ...
      dup /UnderlineThickness known {
    /UnderlineThickness get
    0 exch FontMatrix transform exch pop
    /UnderlineThickness exch def
      } if

If there is NOT an /UnderlineThickness key in the FontInfo dictionary  
then this code leaves a copy of the FontInfo dictionary on the  
operand stack and the remainder of the code does not execute  
correctly. This code should be rewritten to read:

      dup /UnderlineThickness known {
    /UnderlineThickness get
    0 exch FontMatrix transform exch pop
    /UnderlineThickness exch def
      } { % pop the FontInfo dictionary off the operand stack
       pop
    }ifelse

Most PostScript interpreters define these keys in the FontInfo  
dictionary so this code executes without an error. It is only in the  
case where the FontInfo dictionary exists but the /UnderlineThickness  
does not exist in that dictionary that the code fails.

This code fails in a similar fashion with Adobe Distiller.


--
(back to Bill, the bug reporter)
Presumably the same ifelse might be useful in the code handling / 
UnderlinePosition.

  Bill