[l2h] pstoimg bug: 24-bit color depth

[David Pritchard]

I've found a bug in pstoimg.

The -depth command-line parameter and DEPTH environment variable are 
supposed to allow the user to choose the colour depth of the bitmap. 
Valid values are 1, 8 and 24 according to the documentation, and the 
default is 8.

So, I added a $ENV{DEPTH}=24 line to my .latex2html-init file. However, 
pstoimg then generates the following commandline:

Running "/usr/bin/pnmcrop -verbose  < /tmp/l2h9345/p9567.pnm |  | 
/usr/bin/pnmtopng -interlace  > img21.png"

The double pipe causes a shell error, and the image doesn't get 
generated. This is simply due to the way the reduce_color variable is 
used - typically, $reduce_color is set to something like "ppmquant 256". 
When depth is 24, however, there's no need to call ppmquant, and 
$reduce_color is empty. However, the current code still executes a 
$reduce_color command in the pipeline, even though $reduce_color is a 
null command.

The sequence

   if(!$type || $type =~ /(ppm|pgm)/i) {
     if($cmd) {
       $cmd .= "| $reduce_color "
     } else {
       $cmd = "$reduce_color < $in ";
     }
   }

should be changed to

   if((!$type || $type =~ /(ppm|pgm)/i) && $reduce_color) {
     if($cmd) {
       $cmd .= "| $reduce_color "
     } else {
       $cmd = "$reduce_color < $in ";
     }
   }


That should fix the bug,

- David

-- 
David Pritchard                            http://www.david.enigmati.ca
                           drpritch [ at ] cs [ point ] ubc [ point ] ca
Imager Lab, Computer Science Department, University of British Columbia