#!/bin/bash
#
# Developed by Fred Weinhaus 1/22/2008 .......... revised 11/5/2018
#
# ------------------------------------------------------------------------------
# 
# 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: squareup [-s size] [-m mode] [-c color] [-g gravity] [-f filter] infile outfile
# USAGE: squareup [-h or -help]
#
# OPTIONS:
#
# -s      size           desired size; value in pixels or value% as scale factor;
#                        default is same size as input.
# -m      mode           pad or crop; default is pad
# -c      color          background color if pad; any IM color specification 
#                        or none or trans for transparent; default is black
# -g      gravity        gravity location for cropped area; North, East, South 
#                        West or Center; default is Center
# -f      filter         resize filter; any valid IM filter; default is Lanczos
#
###
#
# NAME: SQUAREUP
# 
# PURPOSE: To resize an image and square it up either by padding or cropping.
# 
# DESCRIPTION: SQUAREUP resizes an image and squares it up either by padding it 
# with a constant background color or transparent background or crops it. If 
# padded, the larger dimension will be resized and the smaller dimension will be 
# padded. If cropped, the smaller dimension will be resized and the larger 
# dimension will be cropped. The result will be a square image, i.e. the 
# width and height will be identical.
# 
# 
# OPTIONS: 
# 
#
# -s size ... SIZE specifies the desired output size. The value may be specified 
# as an integer either in pixels or as floating point scale factor in percent 
# (including the % symbol). The default, if left off, is to keep the image the 
# same size.
#
# -m mode ... MODE specifies to either pad or crop the image to square it off. 
# The default is pad.
#
# -c color ... COLOR specifies the background color to use when mode=pad. Any 
# valid IM color specification may be used. To make the background transparent, 
# set the color either to none or trans. The default is black.
# 
# -g gravity ... GRAVITY is the region of the image to use when mode=crop. 
# Values may be North, East, South, West or Center. The default is Center.
#
# -f filter ... FILTER is any valid IM resize filter. The default is Lanczos.
#
# 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
size=""				# size in pixels or %
mode="pad"			# mode: pad or crop
bgcolor="black"		# color or none for transparent
gravity="center"	# gravity location
filter="lanczos"	# resize filter (default=lanczos)


# 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 12 ]
	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
					   ;;
				-s)    # get size
					   shift  # to get the next parameter - size
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID SIZE SPECIFICATION ---"
					   checkMinus "$1"
					   # test size values
					   size=`expr "$1" : '\([.0-9%]*\)'`
					   [ "$size" = "" ] && errMsg "SIZE=$size IS NOT A NUMBER"
					   ;;
		 		-m)    # mode
					   shift  # to get the next parameter - mode
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID MODE SPECIFICATION ---"
					   checkMinus "$1"
					   # test mode values
					   mode="$1"
					   [ "$mode" != "pad" -a "$mode" != "crop" ] && errMsg "--- MODE=$mode IS NOT A VALID VALUE ---"
					   ;;
		 		-c)    # region
					   shift  # to get the next parameter - color
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID BACKGROUND COLOR SPECIFICATION ---"
					   checkMinus "$1"
					   bgcolor="$1"
					   ;;
		 		-g)    # gravity
					   shift  # to get the next parameter - gravity
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID GRAVITY SPECIFICATION ---"
					   checkMinus "$1"
					   # test gravity values
					   gravity="$1"
					   [ "$gravity" != "North" -a "$gravity" != "north" -a "$gravity" != "East" -a "$gravity" != "east" -a "$gravity" != "South" -a "$gravity" != "south" -a "$gravity" != "West" -a "$gravity" != "west" -a "$gravity" != "Center" -a "$gravity" != "center" ] && errMsg "--- GRAVITY=$gravity IS NOT A VALID VALUE ---"
					   ;;
				-f)    # get filter
					   shift  # to get the next parameter - filter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID FILTER SPECIFICATION ---"
					   checkMinus "$1"
					   filter="$1"
					   ;;
 				 -)    # STDIN, 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 and auto delete upon exit
# use mpc/cache to hold input image temporarily in memory
tmpA="$dir/squareup_$$.mpc"
tmpB="$dir/squareup_$$.cache"
trap "rm -f $tmpA $tmpB;" 0
trap "rm -f $tmpA $tmpB; exit 1" 1 2 3 15
trap "rm -f $tmpA $tmpB; exit 1" ERR

# test if infile exists and compute dimensions
if convert -quiet "$infile" +repage "$tmpA"
	then
	width=`identify -format "%w" $tmpA`
	height=`identify -format "%h" $tmpA`
else
	errMsg "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE ---"
fi

# compute max and min dimensions
if [ $width -gt $height ]
	then
	max=$width
	min=$height	
else
	max=$height
	min=$width
fi

if [ "$size" = "" -a "$mode" = "pad" ]
	then 
	dim=$max
elif [ "$size" = "" -a "$mode" = "crop" ]
	then 
	dim=$min
else
	# get % value if specified from size
	factor=`echo "$size" | sed -n 's/\([.0-9]*\)%$/\1/ p'`

	if [ "$factor" = "" ]
		then
		# test if contains a period
		factor2=`echo "$size" | sed -n 's/\([0-9]*[.][0-9]*\)$/\1/ p'`
	    [ "$factor2" != "" ] && errMsg "SIZE=$size IS NOT AN INTEGER"
	fi

	# compute pixel equivalent desired size
	if [ "$factor" = "" -a "$mode" = "pad" ]
		then
		dim=$size
		[ $width -gt $height ] && scale="${dim}x" || scale="x${dim}"
	elif [ "$factor" = "" -a "$mode" = "crop" ]
		then
		dim=$size
		[ $width -gt $height ] && scale="x${dim}" || scale="${dim}x"
	elif [ "$mode" = "pad" ]
		then
		dim=`echo "scale=0; $factor * $max / 100" | bc`
		[ $width -gt $height ] && scale="${dim}x" || scale="x${dim}"
	elif [ "$mode" = "crop" ]
		then
		dim=`echo "scale=0; $factor * $min / 100" | bc`
		[ $width -gt $height ] && scale="x${dim}" || scale="${dim}x"
	fi
fi

# convert trans to none for bgcolor so that background is transparent
[ "$bgcolor" = "trans" ] && bgcolor="none"

# add resize if size != ""
[ "$size" = "" ] && resize="" || resize="-filter $filter -resize $scale"

# process image
if [ "$mode" = "pad" ]
	then
	convert \( -size ${dim}x${dim} xc:$bgcolor \) \( $tmpA $resize \) \
		-gravity $gravity -composite +repage "$outfile"
elif [ "$mode" = "crop" ]
	then
	convert $tmpA $resize -gravity $gravity \
		-crop ${dim}x${dim}+0+0 +repage "$outfile"
fi
exit 0