#!/bin/bash
#
# im_graph 'im_function' image_file
#
# Plot a graph the grayscale modification function given on the command line,
# using gnuplot outpuing a GIF image of the adjustment made to a linear
# greyscale image.
#
####
#
# WARNING: Input arguments are NOT tested for correctness.
# This script represents a security risk if used ONLINE.
# I accept no responsiblity for misuse. Use at own risk.
#
# Anthony Thyssen,  29 June 2008
#
PROGNAME=`type $0 | awk '{print $3}'`  # search for executable on path
PROGDIR=`dirname $PROGNAME`            # extract directory of program
PROGNAME=`basename $PROGNAME`          # base name of program
Usage() {                              # output the script comments as docs
  echo >&2 "$PROGNAME:" "$@"
  sed >&2 -n '/^###/q; /^#/!q; s/^#//; s/^ //; 3s/^/Usage: /; 2,$ p' \
          "$PROGDIR/$PROGNAME"
  exit 10;
}

# while [  $# -gt 0 ]; do
#   case "$1" in
#   --help|--doc*)  Usage ;;   # Documentation
#   -l) line=true ;;
#   -t) shift; title=$1 ;;
#   --) shift; break ;;    # end of user options
#   -*) Usage "Unknown option \"$1\"" ;;
#   *)  break ;;           # end of user options
#   esac
#   shift   # next option
# done

[ $# -eq 0 ] && Usage "Missing im_function"
[ $# -eq 1 ] && Usage "Missing output filename"
[ $# -gt 2 ] && Usage "Too many arguments"

im_func=$1
output=$2

#im_func='-sigmoidal-contrast 8x50%'
#output=show:

# format output, gnuplot image size, and scaling for tic marks
format=png size=160 scale=4     # we want the graph to be 120x120
#format=png size=120 scale=4     # we want the graph to be 120x120
#format=svg size=170 scale=.5   # 3/4 for png  but svg is trial_n_error

# ---------------------------------------------

# Get the background color to use...
[ -f ./generate_options     ] && source ./generate_options
[ -f ../generate_options    ] && source ../generate_options
[ -f ../../generate_options ] && source ../../generate_options
[ "$page_bg_color" ] || page_bg_color=LightSteelBlue

# Gnuplot of a Level function
#exec 2>/dev/null   # just ignore the SVG error output
( echo "set terminal $format size $size,$size"
  echo 'set size square'
  #echo "set bmargin 0.0" # Magins are normally calcualted basied
  #echo "set tmargin 1.0" # on tics, this removes them
  #echo "set lmargin 0.0" # I can't seem to remove margins completely
  #echo "set rmargin 1.0"
  echo "set xtics ( 30, 60, 90 ) scale $scale"
  echo "set ytics ( 0.25, 0.5, 0.75 ) scale $scale"
  echo 'unset key'       # remove function/data plot key
  echo 'set format ""'   # remove tic mark labeling
  #echo 'unset xlabel'
  #echo 'unset ylabel'
  #echo 'unset title'
  #echo 'unset label'
  echo 'set xrange [0:119]'
  echo 'set yrange [0:1]'
  echo -n 'plot "-" binary format="%ushort" endian=big'
  echo    '  array=120 using ($1/65535) with lines'
  convert -size 1x120 gradient: -rotate 90 $im_func \
          -depth 16 -endian MSB gray:-
) | gnuplot |
  #convert - -write info: show:; exit  # DEBUGGING
  convert -background $page_bg_color -bordercolor $page_bg_color \
      label:"0                ½                1" \
      -resize 120x -unsharp 0x.5 -write mpr:label +delete \
      -size 5x118 gradient: +size -rotate 90 -write mpr:gradient \
      $im_func \
      mpr:gradient +swap \
      -bordercolor black -border 1x1 -chop 0x1+0+0 \
      \( +size -background white - -trim +repage \) +insert -append \
      \( mpr:label \) -append \
      \( mpr:label -rotate -90 \) +swap -background $page_bg_color +append \
      -gravity NorthEast -splice 2x2  "$output"

# old label generator
      #-size 500x -fill black -font ArialB \
      #label:"0                ½                1" \
      #-fuzz 20% -trim +repage -border 0x2 \

[ -f "$output" ] && chmod 644 "$output"