#!/bin/bash # # Developed by Fred Weinhaus 10/21/2013 .......... revised 5/7/2015 # # ------------------------------------------------------------------------------ # # 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: xposure [-s stops] [-o offset] [-g gamma] infile outfile # USAGE: xposure [-h or -help] # # OPTIONS: # # -s stops exposure gain in photographic stops; float; default=0 # -o offset exposure offset in fractions; floats; default=0 # -g gamma exposure gamma value; float>0; default=1 # ### # # NAME: XPOSURE # # PURPOSE: To change the exposure level of an image by photographic stops. # # DESCRIPTION: XPOSURE changes the exposure level of an image by photographic # stops to make it either brighter or darker. Linear changes are made according # to output=input*gain+offset. Nonlinear changes are made with gamma. One stop # increase/decrease changes the gain by a factor of 2. # # OPTIONS: # # -s stops ... STOPS controls the exposure gain. Values are floats. One stop # increase/decrease means a doubling/halving of the gain. The default=0 # (no change). # # -o offset ... OFFSET controls the exposure offset in fractions. Values are # floats typically between -1 and 1. The default=0. (no change) # # -g gamma ... GAMMA a non-linear change. Values are floats greater than 0. # The default=1 (no change) # # REQUIREMENT: IM 6.4.8-9 due to the use of -function polynomial. # # 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 stops=0 offset=0 gamma=1 # 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 8 ] 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 stops shift # to get the next parameter # test if parameter starts with minus sign #errorMsg="--- INVALID STOPS SPECIFICATION ---" #checkMinus "$1" stops=`expr "$1" : '\([-.0-9]*\)'` [ "$stops" = "" ] && errMsg "--- STOPS=$stops MUST BE A FLOAT ---" ;; -o) # get offset shift # to get the next parameter # test if parameter starts with minus sign #errorMsg="--- INVALID OFFSET SPECIFICATION ---" #checkMinus "$1" offset=`expr "$1" : '\([-.0-9]*\)'` [ "$offset" = "" ] && errMsg "--- OFFSET=$offset MUST BE A FLOAT ---" ;; -g) # get gamma shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID GAMMA SPECIFICATION ---" checkMinus "$1" gamma=`expr "$1" : '\([-.0-9]*\)'` [ "$gamma" = "" ] && errMsg "--- GAMMA=$gamma MUST BE A FLOAT ---" testA=`echo "$gamma <= 0" | bc` testB=`echo "$gamma > 100" | bc` [ $testA -eq 1 -o $testB -eq 1 ] && errMsg "--- GAMMA=$gamma MUST BE A FLOAT GREATER THAN 0 ---" ;; -) # 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 INFILE FILE SPECIFIED ---" # test that outfile provided [ "$outfile" = "" ] && errMsg "--- NO OUTPUT FILE SPECIFIED ---" tmpA1="$dir/exposure2_A_$$.mpc" tmpA2="$dir/exposure2_A_$$.cache" trap "rm -f $tmpA1 $tmpA2;" 0 trap "rm -f $tmpA1 $tmpA2; exit 1" 1 2 3 15 trap "rm -f $tmpA1 $tmpA2; exit 1" ERR # read the input image into the TMP cached image. convert -quiet "$infile" +repage "$tmpA1" || errMsg "--- FILE $infile NOT READABLE OR HAS ZERO SIZE ---" # 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' | head -n 1` # test if IM version compatible with -function polynomial [ "$im_version" -lt "06040809" ] && errMsg "--- IM VERSION IS NOT COMPATIBLE WITH -FUNCTION POLYNOMIAL ---" # colorspace RGB and sRGB swapped between 6.7.5.5 and 6.7.6.7 # though probably not resolved until the latter if [ "$im_version" -lt "06070606" ]; then cspace1="RGB" cspace2="sRGB" else cspace1="sRGB" cspace2="RGB" fi # compute gain from stop gain=`convert xc: -format "%[fx:pow(2,$stops)]" info:` #echo "gain=$gain; offset=$offset; gamma=$gamma; cspace1=$cspace1; cspace2=$cspace2;" # process image in linear color convert $tmpA1 -colorspace $cspace2 \ -function polynomial "$gain,$offset" -gamma $gamma \ -colorspace $cspace1 "$outfile" exit 0