#!/bin/sh
#
# xbm-mask [options] bitmap/pixmap...
#
#   Take a X bitmap or X pixmap file and CREATE a mask bitmap file of the
# image of either all the white (or black) areas of the image, which are on
# the edges of the image (pbmmask filter). 
#
# For Xpixmaps the transparency becomes white by default.
#
# Any color in a X pixmap which is NOT the background is ensured as being
# part of the resulting mask. This is different to the masking method given
# in the pbmmask manpage which uses a threshold to determine what is and is
# not part of the mask.
# 
# Mask files for X pixmaps are often created for the sole purpose of adding
# the transparent color into the X Pixmap file. 
#
# OPTIONS
#     -t     Background is the X pixmap transparency ONLY
#     -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>
#
# Updated 10 December 1999 for X Pixmap transparency handling
#

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

TRANS="#BFBFBF"  # the transparent color to use. (note xBF => 191)
white=true
b="                                                                  
"

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

# ---- Process Files ----
TMP1=/tmp/xbm-mask$$.1
TMP2=/tmp/xbm-mask$$.2
trap "rm -f $TMP1 $TMP2; 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 it to PbmPlus ---
  name="`basename $i`"
  suffix="`expr "$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 > $TMP1 ;;
    xpm) if [ "$trans" ] && grep 'c  *[Nn]one' "$i" >/dev/null; then
           # set transparency color in pixmap
	   sed "s/c  *[Nn]one/c $TRANS/g" "$i" | x2p.sed |
	     xpmtoppm | pnmdepth 255 2>/dev/null > $TMP1
	 else
           x2p.sed "$i" | xpmtoppm | pnmdepth 255 2>/dev/null > $TMP1 
	 fi ;;
    *)   echo -n "${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

  # Do the task and convert back
  # Note: The output image is white for transparent and black for image.
  # This is vital for things in X windows like cursors etc.
  #
  # Bitmaps and pixmaps with white/black backgrounds...
  # * If white is to be transparent, image is inverted so black is to be
  #   made transparent instead, this makes the `sed' command later easier.
  # * Image is converted to gray scale and colors which are not 0 (black) is
  #   converted to 255 (white) via a `sed' script.
  # * It is then converted to bitmap and pbmmask used to full internal
  #   `holes' in the image, and also inverts the image.
  #
  # Pixmaps with transparency preparation...
  # 
  # Anything which has any RGB value which is not 191 (definately not part
  # of the transparent color is set to 0 (toward black). And any RGB value
  # of 191 is set to 0 (transparency is now black).
  #
  # This should well separate the transparency color from all other colors,
  # including any `close to transparency' color (grey) which may be present.
  # 
  # At this point the normal procedure to mask this image (black being
  # transparent) is followed, except that no final pbmmask is needed so
  # transparent `holes' can be preserved.
  #

  if [ "$trans" -a $suffix = 'xpm' ]; then
    # Pixmap with a transparency color ...
    pnmtoplainpnm $TMP1 | \
      sed '4,${ s/191/T/g; s/[0-9][0-9]*/255/g; s/T/0/g; }' |
        ppmtopgm | pnmtoplainpnm | sed '4,$s/[1-9][0-9]*/255/g' |
          pgmtopbm -threshold | pnminvert > $TMP2
  else
    if [ "$white" ]; then    # invert as black should be transparent
      pnminvert $TMP1 > $TMP2
      mv $TMP2 $TMP1
    fi
    ppmtopgm $TMP1 | pnmtoplainpnm | sed '4,$s/[1-9][0-9]*/255/g' |
      pgmtopbm -threshold | pbmmask $expand > $TMP2
  fi

  if [ ! -f $TMP2 -o ! -s $TMP2 ]; then
    echo -n "${b}"
    echo >&2 "Failed to Create a mask for \"$i\""
    continue
  fi
  
  # --- convert to "_mask.xbm" ---
  pbmtoxbm < $TMP2 |
    sed 's/static  *char/static unsigned char/;
         s/noname\([[_]\)/'"$name"'\1/' > "${name}_mask.xbm"

done
echo "${b}Done"

rm -f $TMP1 $TMP2