#!/usr/bin/env bash
# 
# Developed by Fred Weinhaus 6/20/2009 .......... 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: spherize [-d diameter(s)] [-a amp] [-z zoom] [-b bcolor ] [-s] [-t] infile outfile
# USAGE: spherize [-h or -help]
# 
# OPTIONS:
# 
# -d        diameter(s)         diameters; comma separate x and y diameters;
#                               integers>0 and less than or equal to image
#                               dimensions; if only one value provided, 
#                               it will be used for both; default is the 
#                               image "width,height"
# -a        amp                 distortion amplification factor; float>=0;
#                               default=0
# -z        zoom                zoom factor; scales the input image on the 
#                               sphere; float>=0; default=1
# -b        bcolor              background color; any valid IM color or 
#                               "none" for transparent or "image" for input 
#                               image background; default=black
# -s                            make result with both diameters equal to the  
#                               smaller of the x or y diameters
# -t                            trim image to diameters
# 
###
# 
# NAME: SPHERIZE 
#  
# PURPOSE: To warp an image onto a (hemi-)sphere.
# 
# DESCRIPTION: UNROTATE warps an image onto a (hemi-)sphere and views it 
# orthographically. The x and y diameters can be specified along with the 
# distortion amplification and input image zoom. The background around  
# the sphere is also user controlled. This is a limited version of my 
# bubblewarp script that is not limited by the use of the IM -fx function 
# and therefore is very fast.
# 
# 
# Arguments: 
# 
# -d diameter(s) --- DIAMETER(S) is a comma separate list of the desired 
# x and y diameters of the sphere. If only one value is provided, then it 
# will be used for both diameters. Values are integers greater than zero 
# and equal to or smaller than the dimensions of the image. The default 
# values are the size of the image. Thus if the image is square, then a  
# spherical effect will be produced. But if the image is not square, then 
# elliptical effect will be produced.
# 
# -a amp --- AMP is the distortion amplification factor. Values are floats 
# greater than or equal to zero. The default=1. Values larger than one will 
# make more distortion and values less than one will make less distortion.
#
# -z zoom --- ZOOM is the zoom factor for the input image before warping it 
# onto the sphere. Values are floats greater than or equal to zero. The 
# default=1. Values larger than one will magnify the input image on the sphere. 
# Values less than one will minify the input image on the sphere.
# 
# -b bcolor ... BCOLOR is the color for the background outside the sphere. 
# Any valid IM color is allowed or one may specify "none" for a transparent 
# background or "image" to have the input image as the background. The default 
# is black.
# 
# -s ... Make the result with both diameters equal to the smaller of the 
# x or y diameters.
# 
# -t ... Trim the output image to the diameters.
# 
# NOTE: This script is a limited version of my bubblewarp script, but is 
# much faster, since it does not use -fx.
# 
# NOTE: This script requires IM 6.5.3-9 or higher due to the use of 
# -compose distort. Many thanks to Anthony Thyssen for his hard work 
# developing it.
# 
# 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; 
dx=""					# x diameter
dy=""					# y diameter
amp=1					# distortion amplification
zoom=1					# input image zoom factor
bcolor="black"			# background color; none for transparency; or "image"
symmetry="no"			# sphere with both diameters equal to min of x and y diameters
trim="no"				# trim output to diameters

# 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 parameters
		case "$1" in
	  -h|-help)    # help information
				   echo ""
				   usage2
				   ;;
			-d)    # diameters
				   shift  # to get the next parameter
				   # test if parameter starts with minus sign 
				   errorMsg="--- INVALID DIAMETERS SPECIFICATION ---"
				   checkMinus "$1"
				   diameters=$1
				   test=`echo "$1" | tr "," " " | wc -w`
				   [ $test -eq 1 -o $test -gt 2 ] && errMsg "--- INCORRECT NUMBER OF DIAMETERS SUPPLIED ---"
				   diameters=`expr "$1" : '\([0-9]*,[0-9]*\)'`
				   [ "$diameters" = "" ] && errMsg "--- DIAMETERS=$diameters MUST BE A PAIR OF NON-NEGATIVE INTEGERS SEPARATED BY A COMMA ---"
				   diameters="$1,"
				   dx=`echo "$diameters" | cut -d, -f1`
				   dy=`echo "$diameters" | cut -d, -f2`
				   # further testing done later
				   ;;
			-a)    # amp
				   shift  # to get the next parameter
				   # test if parameter starts with minus sign 
				   errorMsg="--- INVALID AMPLIFICATION SPECIFICATION ---"
				   checkMinus "$1"
				   amp=`expr "$1" : '\([.0-9]*\)'`
				   [ "$amp" = "" ] && errMsg "--- AMPLIFICATION=$amp MUST BE A NON-NEGATIVE FLOATING POINT VALUE (with no sign) ---"
				   ;;
			-z)    # zoom
				   shift  # to get the next parameter
				   # test if parameter starts with minus sign 
				   errorMsg="--- INVALID ZOOM SPECIFICATION ---"
				   checkMinus "$1"
				   zoom=`expr "$1" : '\([.0-9]*\)'`
				   [ "$zoom" = "" ] && errMsg "--- ZOOM=$zoom MUST BE A NON-NEGATIVE FLOATING POINT VALUE (with no sign) ---"
				   ;;
			-b)    # get bcolor
				   shift  # to get the next parameter
				   # test if parameter starts with minus sign 
				   errorMsg="--- INVALID BACKGROUND COLOR SPECIFICATION ---"
				   checkMinus "$1"
				   bcolor="$1"
				   ;;
			-s)    # set symmetry
				   symmetry="yes"
				   ;;
			-t)    # set trim
				   trim="yes"
				   ;;
			 -)    # 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 temporaries
tmpA1="$dir/spherize_A_$$.mpc"
tmpA2="$dir/spherize_A_$$.cache"
tmpB1="$dir/spherize_B_$$.mpc"
tmpB2="$dir/spherize_B_$$.cache"
tmpF1="$dir/spherize_T_$$.mpc"
tmpF2="$dir/spherize_T_$$.cache"
tmpM1="$dir/spherize_M_$$.mpc"
tmpM2="$dir/spherize_M_$$.cache"
tmpX1="$dir/spherize_X_$$.mpc"
tmpX2="$dir/spherize_X_$$.cache"
tmpY1="$dir/spherize_Y_$$.mpc"
tmpY2="$dir/spherize_Y_$$.cache"
trap "rm -f $tmpA1 $tmpA2 $tmpB1 $tmpB2 $tmpF1 $tmpF2 $tmpM1 $tmpM2 $tmpX1 $tmpX2 $tmpY1 $tmpY2;" 0
trap "rm -f $tmpA1 $tmpA2 $tmpB1 $tmpB2 $tmpM1 $tmpM2 $tmpX1 $tmpX2 $tmpY1 $tmpY2; exit 1" 1 2 3 15
trap "rm -f $tmpA1 $tmpA2 $tmpB1 $tmpB2 $tmpM1 $tmpM2 $tmpX1 $tmpX2 $tmpY1 $tmpY2; exit 1" ERR


# read the input image into the TMP cached image.
convert -quiet "$infile" +repage "$tmpA1" ||
	errMsg "--- FILE $infile NOT READABLE OR HAS ZERO SIZE ---"

# test for minimum IM version required
# IM 6.5.3.9 or higher to conform to new -compose distort
im_version=`convert -list configure | \
	sed '/^LIB_VERSION_NUMBER */!d; s//,/;  s/,/,0/g;  s/,0*\([0-9][0-9]\)/\1/g' | head -n 1`
[ "$im_version" -lt "06050309" ] && errMsg "--- REQUIRES IM VERSION 6.5.3-9 OR HIGHER ---"

# get image dimensions
ww=`convert $tmpA1 -ping -format "%w" info:`
hh=`convert $tmpA1 -ping -format "%h" info:`

# set default diameters
if [ "$dx" = "" ]; then
	dx=$ww
fi
if [ "$dy" = "" ]; then
	dy=$hh
fi

# compute min diameter
dm=`convert xc: -format "%[fx:min($dx,$dy)]" info:`
if [ "$symmetry" = "yes" ]; then
	dx=$dm
	dy=$dm
fi

# test diameters
[ $dx -eq 0 -o $dx -gt $ww ] && errMsg "--- X DIAMETER MUST BE GREATER THAN 0 AND LESS OR EQUAL TO IMAGE WIDTH ---"
[ $dy -eq 0 -o $dy -gt $hh ] && errMsg "--- Y DIAMETER MUST BE GREATER THAN 0 AND LESS OR EQUAL TO IMAGE HEIGHT ---"


# scale radius so that that image fits circle or ellipse at any diameter with zoom=1
# invert zoom so increases with larger values
# use absolute coord displacement
# xamount=(rx/zoom)*(ww/dx)=ww/(2*zoom); where rx = x radius
xamount=`convert xc: -format "%[fx:$ww/(2*$zoom+quantumscale)]" info:`
yamount=`convert xc: -format "%[fx:$hh/(2*$zoom+quantumscale)]" info:`


# create radial gradient
convert -size ${dm}x${dm} radial-gradient: -negate $tmpF1

# convert circular gradient to elliptical
if [ $dx -ne $dy ]; then
	convert $tmpF1 -resize ${dx}x${dy}! $tmpF1
fi

# create mask
convert $tmpF1 -negate -gravity center -background black -extent ${ww}x${hh} -threshold 0 $tmpM1

# set up amplify for distortion
if [ "$amp" = "1" ]; then
	amplify=""
else
	amplify="-evaluate pow $amp"
fi

# compute spherize function F=(2/pi)*asin(rd)/rd
convert $tmpF1 \( +clone -function arcsin '2,0,2,0' $amplify \) \
	-compose divide -composite $tmpF1

# set up x displacement
# compute x gradient increasing with i
convert -size ${dy}x${dx} gradient: -rotate 90 $tmpX1

# compute u*v=xd*asin(rd)/rd; u=gradient 0,1; v=asin(rd)/rd 
# but where want xd in range -1,1; so must use (2*u-1)
# then modify to 0.5*u*v+0.5 to recenter at mid gray
# old fx method: 0.5*((2*u-1)*v)+0.5 = u*v - 0.5*v + 0.5
# convert $tmpX1 $tmpF1 -monitor -fx "u*v-0.5*v+0.5" $tmpX1

if [ "$im_version" -ge "06050403" ]; then
	convert $tmpX1 $tmpF1 +swap \
	-compose Mathematics -set option:compose:args "1,0,-0.5,0.5" \
	-composite $tmpX1
else

	# multiply arcsin(r)/(r) by abs of gradient relative to midgray as zero
	# abs is computed as -solarize 50% -level 50,0%
	# abs has V shape and ranges 0 to 1
	# then scale so that range is 0.5 to 1
	#
	# convert gradient to sign of gradient 
	# sign is computed as -threshold 50%
	# thus zero (for neg) on left and one (for pos) on right
	# use sign as mask to separate the right (pos) side, 
	# then negate mask and arcsin-absgrad product 
	# to get the left (neg) side and then combine with right side
	convert $tmpX1 $tmpF1 \
		\( -clone 0 -solarize 50% -level 50,0% \) \
		\( -clone 1,2 -compose multiply -composite -function polynomial "0.5,0.5" \) \
		\( -clone 0 -threshold 50% \) \
		\( -clone 3,4 -compose multiply -composite \) \
		\( -clone 3,4 -negate -compose multiply -composite \) \
		-delete 0-4 -compose plus -composite \
		$tmpX1
fi

# y displacement
if [ $dx -eq $dy ]; then
	# map is symmetric so just rotate x displacement
	convert $tmpX1 -rotate 90 $tmpY1
else
	# compute y gradient increasing with j
	convert -size ${dx}x${dy} gradient: -negate $tmpY1
	
	if [ "$im_version" -ge "06050403" ]; then
		convert $tmpY1 $tmpF1 +swap \
		-compose Mathematics -set option:compose:args "1,0,-0.5,0.5" \
		-composite $tmpY1
	else
		convert $tmpY1 $tmpF1 \
			\( -clone 0 -solarize 50% -level 50,0% \) \
			\( -clone 1,2 -compose multiply -composite -function polynomial "0.5,0.5" \) \
			\( -clone 0 -threshold 50% \) \
			\( -clone 3,4 -compose multiply -composite \) \
			\( -clone 3,4 -negate -compose multiply -composite \) \
			-delete 0-4 -compose plus -composite \
			$tmpY1
	fi
fi

# displace image (center relative)
# absolute coord displacement
convert $tmpA1 $tmpX1 $tmpY1 \
	-gravity center -compose distort \
	-set option:compose:args ${xamount}x${yamount} -composite \
	$tmpB1

# set up trim
if [ "$trim" = "yes" ]; then
	trimming="-gravity center -crop ${dx}x${dy}+0+0 +repage"
else
	trimming=""
fi

# composite mask
if [ "$bcolor" = "none" ]; then
	convert $tmpB1 $tmpM1 \
		-alpha off -compose copy_opacity -composite $trimming "$outfile"
elif [ "$bcolor" = "image" -a "$symmetry" = "no" ]; then
	convert $tmpB1 $trimming "$outfile"
elif [ "$bcolor" = "image" -a "$symmetry" = "yes" ]; then
	convert $tmpA1 $tmpB1 $tmpM1 -compose over -composite $trimming "$outfile"
else
	convert \( $tmpB1 $tmpM1 \
		-gravity center -alpha off -compose copy_opacity -composite \) \
		\( -size ${ww}x${hh} xc:"$bcolor" \) +swap \
		-gravity center -compose over -composite $trimming "$outfile"
fi

exit 0