Code:
#!/bin/bash
# FILE : bbgamma
# Function: Gamma correct all .jpg images in the directory.
# Will either lighten or darken an image depending on the amount of gamma correction required.
# The same color image displayed on two different workstations may look different due to differences
# in the display monitor. Use gamma correction to adjust for this color difference. Reasonable values
# extend from 0.8 to 2.3. Gamma less than 1.0 darkens the image and gamma greater than 1.0 lightens it.
# Copyright (C) 2006-2009 Dave Crouse <crouse@usalug.net>
# ------------------------------------------------------------------------ #
if [[ $1 = "--help" || $1 = "-h" || $1 = "help" ]]; then
echo " Function: Gamma correct all .jpg images in the directory.";
echo " Will either lighten or darken an image depending on the amount of gamma correction required.";
echo " The same color image displayed on two different workstations may look different due to differences ";
echo " in the display monitor. Use gamma correction to adjust for this color difference. Reasonable values ";
echo " extend from 0.8 to 2.3. Gamma less than 1.0 darkens the image and gamma greater than 1.0 lightens it.";
echo " Usage: $0 gamma_number";
echo " Requires: Imagemagick";
echo " EXAMPLE: $0 2.0";
echo " Specify the value between (0.8 - 2.3) 0.8 creating darker images, 2.3 creating lighter images.";
echo " ";
echo " Comments/Suggestions/Bugfixes to <crouse@usalug.net>";
echo " USA Linux Users Group - http://usalug.org";
echo " ";
exit 0
fi
if [[ -z $( type -p convert ) ]]; then echo -e "ImageMagick -- NOT INSTALLED !";exit ;fi
if [ -z "$1" ] ; then
echo " ";
echo " ######### COMMAND FAILED ########## ";
echo " USAGE: $0 gamma_number";
echo " EXAMPLE: $0 2.0";
echo " Specify the value between (0.8 - 2.3) 0.8 creating darker images, 2.3 creating lighter images.";
echo " ######### COMMAND FAILED ########## ";echo " ";
else
export IFS=$'\n';
for i in $(find . -maxdepth 1 -type f -iname "*.jpg");
do
convert -gamma $1 ${i:2} _${i:2};
mv _${i:2} ${i:2}
echo "Gamma corrected image ${i:2}" ;
done
fi
exit 0
