#!/bin/sh -
#
# xpm-remask [-e] [-b] bitmap/pixmap...
#
#   Given a X bitmap or Xpixmap file look for a mask file and output a X
# Pixmap with transparency set according to the mask file found.  Any
# transparency already present in the Xpixmap is lost (converted to white by
# default).
# 
# If no mask file is found, a default mask is created in the same way as
# xbm-mask would, using the options given. The difference here is that
# instead of outputing a mask file, this new default mask is applied
# directly to the pixmap image.
#
# The options below are used to create a mask, only if no mask is already
# present. The same method as xbm-mask is used internaly for this mask
# creation, but the mask file is not created in the current directory.
#
# NOTE that no `transparency' mask is provided (as in xbm-mask), as it is a
# unneeded usless null operation (transparency is set as the transparency!). 
#
# OPTIONS  
#    -b     Background is black - not white
#    -e     Expand mask by one pixel to form a border
#
# Anthony Thyssen    2 September 1995    <anthony@cit.gu.edu.au>
#
b="                                                                        
"
TRANS="#BFBFBF"   # Color used to represent the tranparent color in pbmplus
white=true

# ---- Process options ----
Usage() {
  echo >&2 "Usage: xpm-mask [-e] [-b] bitmap/pixmap..."
  exit 10
}

loop=true
while [ "$loop" ]
do
  case "$1" in
  --) loop=;  shift ;;
  -b) white=; shift ;;          # Black background
  -e) expand=-expand; shift ;;  # Expand mask border
  -*) Usage ;;
  *)  loop= ;;
  esac
done

# ---- Process Files ----
TMP1=/tmp/xpm-mask$$.1    # image
TMP2=/tmp/xpm-mask$$.2
TMPm=/tmp/xpm-mask$$.mask
trap "rm -f $TMP1 $TMP2 $TMPm; exit 1" 1 2 3 15

for i in "$@"; do
  echo -n "${b}  masking \"$i\"
"
  # --- check out this file ---
  if [ ! -r "$i" ]; then
    echo -n "${b}"
    echo >&2 "Unable to read icon \"$i\""
    continue;
  fi

  # --- convert Original to PbmPlus ---
  name="`expr "//$i" : '.*/\([^/]*\)'`"               # remove path
  suffix="`expr "$name" : '.*\.\([^.]*\)'`"
  name="`expr "$name" : '\([^.]*\)'`"
  name="`basename $name _masked`"
  name="`basename $name _recol`"
  name="`basename $name _recol_bad`"

  case "$suffix" in
    xbm)       sed 's/unsigned //' "$i" | xbmtopbm > $TMP1 ;;
    xpm) x2p.sed "$i" | xpmtoppm  > $TMP1 ;;
    *)   echo -n "${b}"
         echo >&2 "Unknown suffix for \"$i\""
         continue ;;
  esac
  if [ ! -f $TMP1 -o ! -s $TMP1 ]; then
    echo -n "${b}"
    echo >&2 "Unable to Convert \"$i\" to Pbmplus"
    continue
  fi

  # --- convert/create mask ---
  if [ -f "${name}_mask.xbm" ]; then
    # Mask is provided -- use it!
    sed 's/unsigned //' "${name}_mask.xbm" | xbmtopbm > $TMPm
  else
    # See notes in xbm-mask on what is happening here
    if [ "$white" ]
    then  pnminvert $TMP1
    else  cat $TMP1
    fi | ppmtopgm | pnmtoplainpnm | sed '4,$s/[1-9][0-9]*/255/g' |
      pgmtopbm -threshold | pbmmask $expand > $TMPm
  fi 
  if [ ! -f $TMPm -o ! -s $TMPm ]; then
    echo -n "${b}"
    echo >&2 "Unable to Create/Find Mask for \"$i\""
    continue
  fi

  # --- Mask the original file ---
  # invert mask so black (0) is transparent then multiply with image.
  pnminvert $TMPm | pnmarith -multiply $TMP1 - >$TMP2  2>/dev/null
  
  # --- Add transparent color into area zero'ed above ---
  pnmdepth 255 $TMPm 2>/dev/null | pgmtoppm "#000-$TRANS" |
    pnmarith -add $TMP2 - >$TMP1

  # --- Output Pixmap ---
  ppmtoxpm $TMP1 2>/dev/null |
    sed "/colors/,/pixels/s/c $TRANS/c None/" |
      xpm-fix -o "${name}_masked.xpm"

done
echo "${b}Done"

rm -f $TMP1 $TMP2 $TMPm