#!/bin/bash
#
# Developed by Fred Weinhaus 3/24/2014 .......... revised 4/25/2015
#
# ------------------------------------------------------------------------------
# 
# 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: mode [-p processing] [-d depth] infile
# USAGE: mode [-h or -help]
# 
# OPTIONS:
# 
# -p     processing        processing of images; choices are: gray (convert 
#                          to grayscale first), global (append all channels 
#                          into one grayscale image), all (process each 
#                          channel separately) and color (find an rgb triplet); 
#                          default=color
# -d     depth             preprocessing depth; 1<=integer<=8; default=8
# 
###
# 
# NAME: MODE 
# 
# PURPOSE: To compute the mode value of an image.
# 
# DESCRIPTION: MODE computes the mode value of an image. The mode is the most 
# frequent color or graylevel in the image. In other words, it is that color 
# or graylevel that has the largest count in the histogram. The user may choose 
# either to process the image to grayscale, to append all the channels into one 
# grayscale image, process each channel separately, or process for a color.
#
# Arguments: 
# 
# -p processing ... PROCESSING of the images. The choices are: gray (convert 
# to grayscale first), global (append all channels into one grayscale image), 
# all (process each channel separately) and color (find an rgb triplet). 
# The default=color
# 
# -d depth DEPTH is the preprocessing image depth. Values are integers 
# between 1 and 8, inclusive. The default=8.
#
# NOTE: This script will process only the first frame/page of a multiframe or 
# multipage image.
#
# 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
processing="color"			# gray, global, all (each channel separately), color
depth=8						# 1 to 8

# 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 5 ]
	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
				   ;;
			-p)    # get processing
				   shift  # to get the next parameter
				   # test if parameter starts with minus sign 
				   errorMsg="--- INVALID PROCESSING SPECIFICATION ---"
				   checkMinus "$1"
				   processing=`echo "$1" | tr "[:upper:]" "[:lower:]"`
				   case "$processing" in
						gray) ;;
						global) ;;
						all) ;;
						color) ;;
						*) errMsg "--- PROCESSING=$processing IS NOT A VALID CHOICE ---" ;;
				   esac
				   ;;
			-d)    # get depth 
				   shift  # to get the next parameter
				   # test if parameter starts with minus sign 
				   errorMsg="--- INVALID DEPTH SPECIFICATION ---"
				   checkMinus "$1"
				   depth=`expr "$1" : '\([1-8]\)'`
				   [ "$depth" = "" ] && errMsg "DEPTH=$depth MUST BE AN INTEGER BETWEEN 1 AND 8"
				   ;;
			 -)    # STDIN and end of arguments
				   break
				   ;;
			-*)    # any other - argument
				   errMsg "--- UNKNOWN OPTION ---"
				   ;;
			 *)    # end of arguments
				   break
				   ;;
			esac
			shift   # next option
	done
	#
	# get infile
	infile="$1"
fi

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

# setup temporary images and auto delete upon exit
tmpA1="$dir/mode_1_$$.mpc"
tmpB1="$dir/mode_1_$$.cache"
trap "rm -f $tmpA1 $tmpB1;" 0
trap "rm -f $tmpA1 $tmpB1; exit 1" 1 2 3 15
trap "rm -f $tmpA1 $tmpB1; exit 1" ERR


# read the input image1 into the temp files and test validity.
convert -quiet "$infile[0]" -alpha off +repage -depth $depth "$tmpA1" ||
	errMsg "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE  ---"


# get colorspace and type for each image
cspace=`identify -ping -verbose $tmpA1 | sed -n 's/^[ ]*Colorspace: \(.*\)$/\1/p'`
type=`identify -ping -verbose $tmpA1 | sed -n 's/^[ ]*Type: \(.*\)$/\1/p'`

# separate into proper colormode
if [ "$type" = "Grayscale" -o "$type" = "Bilevel" ]; then
	colormode="Gray"
elif [ "$cspace" = "sRGB" ]; then
	colormode="RGB"
elif [ "$cspace" = "CMYK" ]; then
	colormode="CMYK"
fi
#echo "type=$type; colormode=$colormode;"

# set up processing
if [ "$processing" = "gray" -a "$colormode" != "Gray" ]; then
	convert $tmpA1 -colorspace gray $tmpA1
	colormode="Gray"
elif [ "$processing" = "global" -a "$colormode" = "RGB" ]; then
	convert $tmpA1 -separate -append $tmpA1
	colormode="Gray"
elif [ "$processing" = "global" -a "$colormode" = "CMYK" ]; then
	convert $tmpA1 -separate -append $tmpA1
	colormode="Gray"
fi
#echo "colormode=$colormode;"


# get sparse IM histogram data for image
histdata=`convert $tmpA1 -depth 8 -format "%c" histogram:info:`

# compute median for channels
if [ "$processing" = "color" ]; then
	mode=`echo "$histdata" | sort -k 1 -r | head -n 1 | sed -n 's/^.*:.*[ ]\(.*\)$/\1/p'`
	echo "$processing: $mode"
		
elif [ "$colormode" = "Gray" ]; then
	mode=`echo "$histdata" | sort -k 1 -r | head -n 1 | tr -cs "[0-9]" " " | sed 's/^ *//' | cut -d\  -f2`
	echo "$processing: $mode"

elif [ "$colormode" = "RGB" ]; then
	mode=`echo "$histdata" | sort -k 1 -r | head -n 1 | tr -cs "[0-9]" " " | sed 's/^ *//' | cut -d\  -f2`
	echo "red: $mode"
	mode=`echo "$histdata" | sort -k 1 -r | head -n 1 | tr -cs "[0-9]" " " | sed 's/^ *//' | cut -d\  -f3`
	echo "green: $mode"
	mode=`echo "$histdata" | sort -k 1 -r | head -n 1 | tr -cs "[0-9]" " " | sed 's/^ *//' | cut -d\  -f4`
	echo "blue: $mode"

elif [ "$colormode" = "CMYK" ]; then
	mode=`echo "$histdata" | sort -k 1 -r | head -n 1 | tr -cs "[0-9]" " " | sed 's/^ *//' | cut -d\  -f2`
	echo "cyan: $mode"
	mode=`echo "$histdata" | sort -k 1 -r | head -n 1 | tr -cs "[0-9]" " " | sed 's/^ *//' | cut -d\  -f3`
	echo "magenta: $mode"
	mode=`echo "$histdata" | sort -k 1 -r | head -n 1 | tr -cs "[0-9]" " " | sed 's/^ *//' | cut -d\  -f4`
	echo "yellow: $mode"
	mode=`echo "$histdata" | sort -k 1 -r | head -n 1 | tr -cs "[0-9]" " " | sed 's/^ *//' | cut -d\  -f5`
	echo "black: $mode"
fi

exit 0