#!/bin/bash
#
# Developed by Fred Weinhaus 1/31/2017 .......... revised 8/15/2022
#
# ------------------------------------------------------------------------------
# 
# Licensing:
# 
# Copyright © Fred Weinhaus
# 
# My scripts are available free of charge for non-commercial use, ONLY.
# 
# For use of my scripts in commercial (for-profit) environments or 
# non-free applications, please contact me (Fred Weinhaus) for 
# licensing arrangements. My email address is fmw at alink dot net.
# 
# If you: 1) redistribute, 2) incorporate any of these scripts into other 
# free applications or 3) reprogram them in another scripting language, 
# then you must contact me for permission, especially if the result might 
# be used in a commercial or for-profit environment.
# 
# My scripts are also subject, in a subordinate manner, to the ImageMagick 
# license, which can be found at: http://www.imagemagick.org/script/license.php
# 
# ------------------------------------------------------------------------------
# 
####
#
# USAGE: removecolorcast [-m mixing] [-a autolevel] [-c cspace] 
# [-B brightness] [-C contrast] [-S saturation] [infile] [outfile]
# 
# USAGE: removecolorcast [-h|-help]
# 
# OPTIONS:
# 
# -m     mixing         mixing amount between input image and color filter;
#                       0<=integer<=100; default=50
# -c     cpsace         colorspace for processing; choices are: sRGB or RGB;
#                       default=sRGB
# -a     autolevel      stretch the result to full dynamic range; yes or no; 
#                       the default=yes
# -B     brightness     brightness change postprocessing; -100<=integer<=100; 
#                       default=0
# -C     contrast       contrast change postprocessing; -100<=integer<=100; 
#                       default=0
# -S     saturation     saturation change postprocessing; -100<=integer<=1000; 
#                       default=0
#
###
# 
# NAME: REMOVECOLORCAST 
# 
# PURPOSE: To remove a color cast from an image.
# 
# DESCRIPTION: REMOVECOLORCAST removes a color cast from an image by blending 
# the image and a color filter generated from the 180 deg hue shifted average 
# color of the image. The method of filtering use -compose colorize. 
# 
# 
# ARGUMENTS: 
# 
# -m mixing ... MIXING amount between the input image and a self generating 
# color filter. The values are 0<=integers<=100. The default=50.
# 
# -c cpsace ... CSPACE is the colorspace for processing. The choices are: 
# sRGB or RGB. The default=sRGB. Using sRGB results in a slightly warmer 
# result. Using RGB results in a slightly cooler result.
# 
# -a autolevel ... AUTOLEVEL applies a dynamic range stretch of the result. 
# The choices are: yes or no. The default=yes.
# 
# -B brightness ... BRIGHTNESS change as a postprocessing step. Value are 
# -100<=integer<=100. The default=0.
# 
# -C contrast ... CONTRAST change as a postprocessing step. Value are 
# -100<=integer<=100. The default=0.
# 
# -S saturation ... SATURATION change as a postprocessing step. Value are 
# -100<=integer<=100. The default=0.
# 
# RECOMMEND: IM 6.8.5.4 or higher due to fluctuating changes to IM sRGB and 
# RGB color spaces prior to that version. Otherwise, results may or may not  
# reproduce the effect properly, depending upon IM version. 
# 
# CAVEAT: No guarantee that this script will work on all platforms, 
# nor that trapping of inconsistent parameters is complete and 
# foolproof. Use At Your Own Risk. 
# 
######
# 
# set default values
mixing=50			# mixing (blend) amount; 0<=integer<=100
autolevel="yes"		# autolevel postprocess
cspace="SRGB"		# process in sRGB or RGB
brightness=0        # brightness change postprocess; -100<=integer<=100
contrast=0			# contrast change postprocess; -100<=integer<=100
saturation=0        # saturation change postprocess; -100<=integer<=100

# set directory for temporary files
dir="."    # suggestions are dir="." or dir="/tmp"

# set up functions to report Usage and Usage with Description
PROGNAME=`type $0 | awk '{print $3}'`  # search for executable on path
PROGDIR=`dirname $PROGNAME`            # extract directory of program
PROGNAME=`basename $PROGNAME`          # base name of program
usage1() 
	{
	echo >&2 ""
	echo >&2 "$PROGNAME:" "$@"
	sed >&2 -e '1,/^####/d;  /^###/g;  /^#/!q;  s/^#//;  s/^ //;  4,$p' "$PROGDIR/$PROGNAME"
	}
usage2() 
	{
	echo >&2 ""
	echo >&2 "$PROGNAME:" "$@"
	sed >&2 -e '1,/^####/d;  /^######/g;  /^#/!q;  s/^#*//;  s/^ //;  4,$p' "$PROGDIR/$PROGNAME"
	}


# function to report error messages
errMsg()
	{
	echo ""
	echo $1
	echo ""
	usage1
	exit 1
	}


# function to test for minus at start of value of second part of option 1 or 2
checkMinus()
	{
	test=`echo "$1" | grep -c '^-.*$'`   # returns 1 if match; 0 otherwise
    [ $test -eq 1 ] && errMsg "$errorMsg"
	}

# test for correct number of arguments and get values
if [ $# -eq 0 ]
	then
	# help information
   echo ""
   usage2
   exit 0
elif [ $# -gt 14 ]
	then
	errMsg "--- TOO MANY ARGUMENTS WERE PROVIDED ---"
else
	while [ $# -gt 0 ]
		do
			# get parameter values
			case "$1" in
		 -h|-help)    # help information
					   echo ""
					   usage2
					   exit 0
					   ;;
				-m)    # get mixing
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID MIXING SPECIFICATION ---"
					   #checkMinus "$1"
					   mixing=`expr "$1" : '\([-0-9]*\)'`
					   [ "$mixing" = "" ] && errMsg "--- MIXING=$mixing MUST BE A NON-NEGATIVE INTEGER ---"
					   testA=`echo "$mixing < -100" | bc`
					   testB=`echo "$mixing > 100" | bc`
					   [ $testA -eq 1 -o $testB -eq 1 ] && errMsg "--- MIXING=$mixing MUST BE AN INTEGER BETWEEN -100 AND 100 ---"
					   ;;
				-c)    # get cspace
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID CSPACE SPECIFICATION ---"
					   checkMinus "$1"
					   cspace=`echo "$1" | tr "[:lower:]" "[:upper:]"`
					   [ "$cspace" != "SRGB" -a "$cspace" != "RGB" ] && errMsg "--- CSPACE=$cspace MUST BE EITHER sRGB OR RGB ---"
					   ;;
				-a)    # get autolevel
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID AUTOLEVEL SPECIFICATION ---"
					   checkMinus "$1"
					   autolevel=`echo "$1" | tr "[:upper:]" "[:lower:]"`
					   [ "$autolevel" != "yes" -a "$autolevel" != "no" ] && errMsg "--- AUTOLEVEL=$autolevel MUST BE EITHER YES OR NO ---"
					   ;;
				-B)    # get brightness
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID BRIGHTNESS SPECIFICATION ---"
					   #checkMinus "$1"
					   brightness=`expr "$1" : '\([-0-9]*\)'`
					   [ "$brightness" = "" ] && errMsg "--- BRIGHTNESS=$brightness MUST BE A NON-NEGATIVE INTEGER ---"
					   testA=`echo "$brightness < -100" | bc`
					   testB=`echo "$brightness > 100" | bc`
					   [ $testA -eq 1 -o $testB -eq 1 ] && errMsg "--- BRIGHTNESS=$brightness MUST BE AN INTEGER BETWEEN -100 AND 100 ---"
					   ;;
				-C)    # get contrast
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID CONTRAST SPECIFICATION ---"
					   #checkMinus "$1"
					   contrast=`expr "$1" : '\([-0-9]*\)'`
					   [ "$contrast" = "" ] && errMsg "--- CONTRAST=$contrast MUST BE A NON-NEGATIVE INTEGER ---"
					   testA=`echo "$contrast < -100" | bc`
					   testB=`echo "$contrast > 100" | bc`
					   [ $testA -eq 1 -o $testB -eq 1 ] && errMsg "--- CONTRAST=$contrast MUST BE AN INTEGER BETWEEN -100 AND 100 ---"
					   ;;
				-S)    # get saturation
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID SATURATION SPECIFICATION ---"
					   #checkMinus "$1"
					   saturation=`expr "$1" : '\([-0-9]*\)'`
					   [ "$saturation" = "" ] && errMsg "--- SATURATION=$saturation MUST BE A NON-NEGATIVE INTEGER ---"
					   testA=`echo "$saturation < -100" | bc`
					   testB=`echo "$saturation > 1000" | bc`
					   [ $testA -eq 1 -o $testB -eq 1 ] && errMsg "--- SATURATION=$saturation MUST BE AN INTEGER BETWEEN -100 AND 100 ---"
					   ;;
				 -)    # STDIN and end of arguments
					   break
					   ;;
				-*)    # any other - argument
					   errMsg "--- UNKNOWN OPTION ---"
					   ;;
		     	 *)    # end of arguments
					   break
					   ;;
			esac
			shift   # next option
	done
	#
	# get infile and outfile
	infile="$1"
	outfile="$2"
fi

# test that infile provided
[ "$infile" = "" ] && errMsg "NO INPUT FILE SPECIFIED"

# test that outfile provided
[ "$outfile" = "" ] && errMsg "NO OUTPUT FILE SPECIFIED"


# setup temporary images
tmpI="$dir/REMOVECOLORCAST_$$.miff"
trap "rm -f $tmpI; exit 0" 0
trap "rm -f $tmpI; exit 1" 1 2 3 15


# read the input image into the temporary cached image and test if valid
convert -quiet -regard-warnings "$infile" +repage "$tmpI" ||
	echo "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO size  ---"


# set up auto-level
if [ "$autolevel" = "yes" ]; then
	stretch="-auto-level"
else
	stretch=""
fi
#echo "stretch=$stretch"

# set up brightness and saturation
bval=$((100+brightness))
sval=$((100+saturation))
modulating="-set option:modulate HSB -modulate $bval,$sval,100"
echo "bval=$bval; sval=$sval; modulating=$modulating;"

# setup contrast
if [ $contrast != 0 ]; then
	contrasting="-brightness-contrast 0,$contrast"
else
	contrasting=""
fi

# get image dimensions
WxH=`convert $tmpI -format "%wx%h" info:`

# do processing
# get average color and negate via 180 hue change and make constant color the size of input
# then blend with original image via -compose colorize

convert $tmpI \
	\( -clone 0 -colorspace $cspace -resize 1x1! -resize $WxH\! -modulate 100,100,0 \) \
	\( -clone 0 -fill "gray($mixing%)" -colorize 100 \) \
	-compose colorize -composite -colorspace sRGB \
	$stretch $contrasting $modulating \
	"$outfile"


exit 0