#!/bin/csh -f
# Usage: ps_no_bleedthrough ps_file
#
# Ferret PostScript files that contain shaded or filled regions
# often yield poor results upon conversion to PNG, GIF, etc. with
# antialiasing, since the edges of interior rectangles are blended
# with the background color.  This produces "stripes" or a "grid"
# of the background color "bleeding through" the shaded areas.
# This script reduces this effect, by slightly altering the PostScript.
# Result goes to standard output.
#
# Authors: Andrew Wittenberg, Rong Zhang
# Version dated 21 January 2011

# get list of all arguments
set args = ($*)

# if not enough arguments, complain.
if ($#args < 1) then
   echo "Usage: ps_no_bleedthrough ps_file"
   echo "Reduces bleed-through of PostScript background color when converting"
   echo "to an antialiased rasterized image (PNG, GIF, etc.)."
   echo "Result goes to standard output."
   echo "Example: ps_no_bleedthrough myfile.ps > myfile_new.ps"
   exit 1
endif

sed -e 's,^/cp {closepath} def$,/cp {closepath gsave fill grestore stroke} def,' \
    -e '/\/rect {/,/} def/ s,^   cp$,%   cp,' $1