#!/bin/bash
# 
# Developed by Fred Weinhaus 12/29/2018 .... revised 6/2/2025
#
# ------------------------------------------------------------------------------
# 
# 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: trim2rect [-f fuzzval] [-c coords] [-b bgcolor] [-p progress] [-g graphic] 
# [-d dcolor] [-s sides] infile outfile
# USAGE: trim2rect [-h or -help]
# 
# OPTIONS:
# 
# -f     fuzzval      fuzz value for determining border color; expressed as (float) 
#                     percent 0 to 100; default=0 (uniform color)
# -c     coords       pixel coordinate to extract color; may be expressed as a 
#                     gravity value (NorthWest, etc) or as "x,y" value; default 
#                     is NorthWest=(0,0)
# -b     bgcolor      background color surrounding region of interest; any valid IM 
#                     color is allowed; default is to use coords to get color; bgcolor 
#                     takes precedence over coordinates
# -p     progress     show progress; choices are: yes or no
# -g     graphic      draw crop box on input image; yes or no; default=no; graphic 
#                     image will be the input image name with _cropbox.jpg appended
# -d     dcolor       crop box draw color; any valid opaque IM color is allowed: 
#                     default=red
# -s     sides        the sides to trim; choices are LR (for left and right),  
#                     TB (for top and bottom) or A (for all four sides)
# 
###
# 
# NAME: TRIM2RECT 
#  
# PURPOSE: Automatically trims the sides of an image until no outer row or column
# contains the background color. 
# 
# DESCRIPTION: TRIM2RECT automatically trims the sides of an image one row or column 
# at a time until no side row or column contains the background color. The background 
# color is first floodfilled to be transparent and a -trim is performed to remove 
# excess background color that is completely along any side. Then the alpha channel is 
# extracted. Each side row or column of the alpha channel is then tested for its 
# mean value. If the mean value is less than one, a counter is incremented for that 
# side. Once a side row or column of the alpha channel has a mean of 1, that side row 
# or column is no longer tested. Processing continues until all side rows and columns 
# have a mean value of 1. A crop box is then computed from the counters indicating 
# how many rows and columns should be removed from each side. Finally the image is 
# cropped.
# 
# 
# Arguments: 
# 
# -f fuzzval ... FUZZVAL is the fuzz amount specified as a percent 0 to 100 
# (without the % sign). The default=5. A value of zero indicates that border is a 
# uniform color. Larger values are needed when the border is not a uniform color.
# 
# -c coords ... COORDS is any location within the border area for the 
# algorithm to find the base border color. It may be specified in terms of 
# gravity parameters (NorthWest, North, NorthEast, East, SouthEast, South, 
# SouthWest or West) or as a pixel coordinate "x,y". The default is the 
# upper left corner = NorthWest = "0,0".
# 
# -bg color ... BGCOLOR is the background color surrounding the region of interest. 
# Any valid IM color is allowed. The default is to use coords to get color. The 
# bgcolor takes precedence over coordinates.
# 
# -p progress... show PROGRESS in cycles. The choices are: yes (y) or no (n). Each  
# cycle corresponds to a test of all four sides in the order of top, left, bottom, 
# right.
# 
# -g graphic ... GRAPHIC specifies to draw the crop box on input image after the 
# initial -trim to remove excess border. Choices are: yes (y) or no (n). The default=no. 
# The graphic image will be the input image name with _cropbox.jpg appended.
# 
# -d dcolor ... DCOLOR is the crop box draw color. Any valid opaque IM color is allowed. 
# The default=red.
#
# -s sides ... SIDES to trim. The choices are LR (for left and right),  
# TB (for top and bottom) or A (for all four sides)
# 
# Note, this script may be quite slow as it processes one row or column at a time.
# 
# 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
fuzzval=5
bgcolor=""
coord="0,0"
progress="no"
graphic="no"
dcolor="red"
sides="all"

# set directory for temporary files
# tmpdir="/tmp"
tmpdir="."

# 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 16 ]
	then
	errMsg "--- TOO MANY ARGUMENTS WERE PROVIDED ---"
else
	while [ $# -gt 0 ]
		do
		# get parameters
		case "$1" in
	  -h|-help)    # help information
				   echo ""
				   usage2
				   ;;
			-f)    # fuzzval
				   shift  # to get the next parameter - fuzzval
				   # test if parameter starts with minus sign 
				   errorMsg="--- INVALID FUZZVAL SPECIFICATION ---"
				   checkMinus "$1"
				   fuzzval=`expr "$1" : '\([.0-9]*\)'`
				   [ "$fuzzval" = "" ] && errMsg "--- FUZZVAL=$fuzzval MUST BE A NON-NEGATIVE FLOATING POINT VALUE (with no sign) ---"
				   fuzzvaltest=`echo "$fuzzval < 0" | bc`
				   [ $fuzzvaltest -eq 1 ] && errMsg "--- FUZZVAL=$fuzzval MUST BE A NON-NEGATIVE FLOATING POINT VALUE ---"
				   ;;
			-c)    # coords
				   shift  # to get the next parameter - coords
				   # test if parameter starts with minus sign 
				   errorMsg="--- INVALID COORDS SPECIFICATION ---"
				   checkMinus "$1"
				   coords=$1
				   # further testing done later
				   ;;
			-b)    # bgcolor
				   shift  # to get the next parameter - coords
				   bgcolor="$1"
				   ;;
			-p)    # get progress
				   shift  # to get the next parameter
				   # test if parameter starts with minus sign
				   errorMsg="--- INVALID PROGRESS SPECIFICATION ---"
				   checkMinus "$1"
				   progress=`echo "$1" | tr "[:upper:]" "[:lower:]"`
				   case "$progress" in
						yes|y) progress="yes";;
						no|n) progress="no";;
						*)  errMsg "--- PROGRESS=$progress IS NOT A VALID VALUE ---" ;;
				   esac
				   ;;
			-g)    # get graphic
				   shift  # to get the next parameter
				   # test if parameter starts with minus sign
				   errorMsg="--- INVALID GRAPHIC SPECIFICATION ---"
				   checkMinus "$1"
				   graphic=`echo "$1" | tr "[:upper:]" "[:lower:]"`
				   case "$graphic" in
						yes|y) graphic="yes";;
						no|n) graphic="no";;
						*)  errMsg "--- GRAPHIC=$graphic IS NOT A VALID VALUE ---" ;;
				   esac
				   ;;
			-d)    # dcolor
				   shift  # to get the next parameter - coords
				   dcolor="$1"
				   ;;
			-s)    # sides
				   shift  # to get the next parameter
				   # test if parameter starts with minus sign
				   errorMsg="--- INVALID SIDES SPECIFICATION ---"
				   checkMinus "$1"
				   sides=`echo "$1" | tr "[:upper:]" "[:lower:]"`
				   case "$sides" in
						LR|lr) sides="lr";;
						TB|tb) sides="tb";;
						A|a|ALL|all) sides="all";;
						*)  errMsg "--- SIDES=$sides IS NOT A VALID VALUE ---" ;;
				   esac
				   ;;
			 -)    # 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"


dir="$tmpdir/TRIM2RECT.$$"

mkdir "$dir" || errMsg "--- FAILED TO CREATE TEMPORARY FILE DIRECTORY ---"
trap "rm -rf $dir; exit 0" 0
trap "rm -rf $dir; exit 1" 1 2 3 15

# get IM version
im_version=`convert -list configure | \
	sed '/^LIB_VERSION_NUMBER */!d;  s//,/;  s/,/,0/g;  s/,0*\([0-9][0-9]\)/\1/g'`

# set up floodfill
if [ "$im_version" -ge "07000000" ]; then
	matte_alpha="alpha"
else
	matte_alpha="matte"
fi

# test if infile exist
if ! [ -f "$infile" -a -e "$infile" -a -r "$infile" -a -s "$infile" ]; then
	errMsg  "--- FILE $dfile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE  ---"
	exit 1
fi


# test if coords provided as x,y and not gravity values
coords1=`expr "$coords" : '\([0-9]*,[0-9]*\)'`

# get coords if not supplied and bgcolor not none or transparent
if [ "$bgcolor" != "none" -a "$bgcolor" != "transparent" ]; then
	if [ "$coords1" = "" ]; then
		WxH=`convert -ping -quiet "$infile[0]" -format "%wx%h" info:`
		width=`echo $WxH | cut -dx -f1`
		height=`echo $WxH | cut -dx -f2`
		widthm1=`convert xc: -format "%[fx:$width-1]" info:`
		heightm1=`convert xc: -format "%[fx:$height-1]" info:`
		midwidth=`convert xc: -format "%[fx:round(($width-1))/2]" info:`
		midheight=`convert xc: -format "%[fx:round(($height-1))/2]" info:`
		coords=`echo "$coords" | tr "[:upper:]" "[:lower:]"`
		case "$coords" in
			''|nw|northwest) coords="0,0" ;;
			n|north)         coords="$midwidth,0" ;;
			ne|northeast)    coords="$widthm1,0" ;;
			e|east)          coords="$widthm1,$midheight" ;;
			se|southeast)    coords="$widthm1,$heightm1" ;;
			s|south)         coords="$midwidth,$heightm1" ;;
			sw|southwest)    coords="0,$heightm1" ;;
			w|west)          coords="0,$midheight" ;;
			*)  errMsg "--- INVALID COORDS ---" ;;
		esac
		bgcolor=`convert "$infile[0]" -format "%[pixel:u.p{$coords}]" info:`
	else
		bgcolor=`convert "$infile[0]" -format "%[pixel:u.p{$coords}]" info:`
	fi
fi

# set up for floodfill if bgcolor not none or transparnt
if [ "$bgcolor" != "none" -a "$bgcolor" != "transparent" ]; then
	proc="-fill none -draw \"$matte_alpha $coord floodfill\""
else
	proc=""
fi


# read the input
convert -quiet "$infile[0]" +repage $dir/tmpO.mpc ||
errMsg  "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE  ---"

# get original dimensions
declare `convert -ping $dir/tmpO.mpc -format "wwo=%w\nhho=%h\n" info:`
#echo "wwo=$wwo; hho=$hho;"


# do fuzzy trim
#convert -quiet "$infile[0]" +repage $dir/tmpI.mpc ||
eval 'convert -quiet $dir/tmpO.mpc -bordercolor "$bgcolor" -border 1 -fuzz $fuzzval% '$proc' -trim $dir/tmpI.mpc'

# get trimbounds
trimbounds=`convert -ping $dir/tmpI.mpc -format "%w+%h%O" info:`
ww=`echo $trimbounds | cut -d+ -f1`
hh=`echo $trimbounds | cut -d+ -f2`
xx=`echo $trimbounds | cut -d+ -f3`
yy=`echo $trimbounds | cut -d+ -f4`
#echo "ww=$ww; hh=$hh; xx=$xx; yy=$yy;"

# compute change in size and offset accounting for border pad by 1 all around
dxo=$((xx-1))
dyo=$((yy-1))
#echo "dxo=$dxo; dyo=$dyo;"


# extract alpha (be sure to repage since not done after -trim above)
convert $dir/tmpI.mpc +repage -alpha extract $dir/tmpA.mpc

# circulate around the outside edges and chop the side that has the smallest opacity; stop if opacity is fully white
top="transparent"
left="transparent"
bottom="transparent"
right="transparent"
top_count=0
left_count=0
bottom_count=0
right_count=0
i=0
mean_top=`convert $dir/tmpA.mpc -gravity north -crop 0x1+0+0 +repage -scale 1x1! -format "%[fx:u]" info:`
mean_left=`convert $dir/tmpA.mpc -gravity west -crop 1x0+0+0 +repage -scale 1x1! -format "%[fx:u]" info:`
mean_bottom=`convert $dir/tmpA.mpc -gravity south -crop 0x1+0+0 +repage -scale 1x1! -format "%[fx:u]" info:`
mean_right=`convert $dir/tmpA.mpc -gravity east -crop 1x0+0+0 +repage -scale 1x1! -format "%[fx:u]" info:`
mean_min=`convert xc: -format "%[fx:min(min(min($mean_top,$mean_left),$mean_bottom),$mean_right)]" info:`
echo "mean_top=$mean_top; mean_left=$mean_left; mean_bottom=$mean_bottom; mean_right=$mean_right; mean_min=$mean_min;"

until [ "$top" = "opaque" -a "$left" = "opaque" -a "$bottom" = "opaque" -a "$right" = "opaque" ]; do
	#echo "i=$i; mean_top=$mean_top; mean_left=$mean_left; mean_bottom=$mean_bottom; mean_right=$mean_right; mean_min=$mean_min;"
	
	# test each side to see if transparent
	# if transparent, then test if mean != 1
	# if mean != 1, then test if mean = min
	# if mean = min, then increment counter and continue loop
	# if mean = 1, then set side to opaque
	
	if [ "$top" = "transparent" ]; then
		if [ "$mean_top" != "1" ]; then
			top_test=`echo "$mean_top==$mean_min" | bc`
			#echo "top_test=$top_test"
			if [ $top_test -eq 1 ]; then
				#echo "i=$i; top_count=$top_count; mean_top=$mean_top;"
				((top_count++))
				wd=$((ww-left_count-right_count))
				ht=$((hh-top_count-bottom_count))
				mean_top=`convert $dir/tmpA.mpc -gravity northwest -crop ${wd}x1+${left_count}+${top_count} +repage -scale 1x1! -format "%[fx:u]" info:`
				mean_left=`convert $dir/tmpA.mpc -gravity northwest -crop 1x${ht}+${left_count}+${top_count} +repage -scale 1x1! -format "%[fx:u]" info:`
				mean_right=`convert $dir/tmpA.mpc -gravity northeast -crop 1x${ht}+${right_count}+${top_count} +repage -scale 1x1! -format "%[fx:u]" info:`
				mean_min=`convert xc: -format "%[fx:min(min(min($mean_top,$mean_left),$mean_bottom),$mean_right)]" info:`
				((i++))
				echo "iteration=$i; top_count=$top_count; mean_top=$mean_top"
				continue
			fi
		else
			top="opaque"
			echo "top is opaque"
		fi
	fi
			
	if [ "$left" = "transparent" ]; then
		if [ "$mean_left" != "1" ]; then
			left_test=`echo "$mean_left==$mean_min" | bc`
			#echo "left_test=$left_test"
			if [ $left_test -eq 1 ]; then
				#echo "i=$i; left_count=$left_count; mean_left=$mean_left;"
				((left_count++))
				wd=$((ww-left_count-right_count))
				ht=$((hh-top_count-bottom_count))
				mean_left=`convert $dir/tmpA.mpc -gravity northwest -crop 1x${ht}+${left_count}+${top_count} +repage -scale 1x1! -format "%[fx:u]" info:`
				mean_top=`convert $dir/tmpA.mpc -gravity northwest -crop ${wd}x1+${left_count}+${top_count} +repage -scale 1x1! -format "%[fx:u]" info:`
				mean_bottom=`convert $dir/tmpA.mpc -gravity southwest -crop ${wd}x1+${left_count}+${bottom_count} +repage -scale 1x1! -format "%[fx:u]" info:`
				mean_min=`convert xc: -format "%[fx:min(min(min($mean_top,$mean_left),$mean_bottom),$mean_right)]" info:`
				((i++))
				echo "iteration=$i; left_count=$left_count; mean_left=$mean_left"
				continue
			fi
		else
			left="opaque"
			echo "left is opaque"
		fi
	fi

	if [ "$bottom" = "transparent" ]; then
		if [ "$mean_bottom" != "1" ]; then
			bottom_test=`echo "$mean_bottom==$mean_min" | bc`
			#echo "bottom_test=$bottom_test"
			if [ $bottom_test -eq 1 ]; then
				#echo "i=$i; bottom_count=$bottom_count; mean_bottom=$mean_bottom;"
				((bottom_count++))
				wd=$((ww-left_count-right_count))
				ht=$((hh-top_count-bottom_count))
				mean_bottom=`convert $dir/tmpA.mpc -gravity southwest -crop ${wd}x1+${left_count}+${bottom_count} +repage -scale 1x1! -format "%[fx:u]" info:`
				mean_left=`convert $dir/tmpA.mpc -gravity northwest -crop 1x${ht}+${left_count}+${top_count} +repage -scale 1x1! -format "%[fx:u]" info:`
				mean_right=`convert $dir/tmpA.mpc -gravity northeast -crop 1x${ht}+${right_count}+${top_count} +repage -scale 1x1! -format "%[fx:u]" info:`
				mean_min=`convert xc: -format "%[fx:min(min(min($mean_top,$mean_left),$mean_bottom),$mean_right)]" info:`
				((i++))
				echo "iteration=$i; bottom_count=$bottom_count; mean_bottom=$mean_bottom"
				continue
			fi
		else
			bottom="opaque"
			echo "bottom is opaque"
		fi
	fi
			
	if [ "$right" = "transparent" ]; then
		if [ "$mean_right" != "1" ]; then
			right_test=`echo "$mean_right==$mean_min" | bc`
			#echo "right_test=$right_test"
			if [ $right_test -eq 1 ]; then
				#echo "i=$i; right_count=$right_count; mean_right=$mean_right;"
				((right_count++))
				wd=$((ww-left_count-right_count))
				ht=$((hh-top_count-bottom_count))
				mean_right=`convert $dir/tmpA.mpc -gravity northeast -crop 1x${ht}+${right_count}+${top_count} +repage -scale 1x1! -format "%[fx:u]" info:`
				mean_top=`convert $dir/tmpA.mpc -gravity northwest -crop ${wd}x1+${left_count}+${top_count} +repage -scale 1x1! -format "%[fx:u]" info:`
				mean_bottom=`convert $dir/tmpA.mpc -gravity southwest -crop ${wd}x1+${left_count}+${bottom_count} +repage -scale 1x1! -format "%[fx:u]" info:`
				mean_min=`convert xc: -format "%[fx:min(min(min($mean_top,$mean_left),$mean_bottom),$mean_right)]" info:`
				((i++))
				echo "iteration=$i; right_count=$right_count; mean_right=$mean_right"
				continue
			fi
		else
			right="opaque"
			echo "right is opaque"
		fi
	fi

done

#echo "ww=$ww; hh=$hh; left_count=$left_count; right_count=$right_count; top_count=$top_count; bottom_count=$bottom_count;"

# get crop coordinates
xc=$((left_count+dxo))
yc=$((top_count+dyo))
wwc=$((ww-right_count-left_count))
hhc=$((hh-bottom_count-top_count))

if [ "$sides" = "lr" ]; then
	yc=0
	hhc=$hho
elif [ "$sides" = "tb" ]; then
	xc=0
	wwc=$wwo
fi
cropbox="${wwc}x${hhc}+${xc}+${yc}"
echo "cropbox=$cropbox;"


# crop
convert $dir/tmpO.mpc -crop $cropbox "$outfile"


# draw crop box
if [ "graphic" = "yes" ]; then
	left_count0=$xc
	top_count0=$yc
	right_count0=$((xc+wwc-1))
	bottom_count0=$((yc+hhc-1))
	#echo "left_count0=$left_count0; right_count0=$right_count0; top_count0=$top_count0; bottom_count0=$bottom_count0;"

	draw_coords="$left_count0,$top_count0 $right_count0,$bottom_count0"
	convert $dir/tmpO.mpc -fill none -stroke red -draw "rectangle $draw_coords" -alpha off ${inname}_cropboxE.jpg
fi

exit 0