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|
#!/bin/bash
#
# Developed by Fred Weinhaus 10/29/2008 .......... revised 11/3/2015
#
# ------------------------------------------------------------------------------
#
# 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: 2colorthresh infile outfile
# USAGE: 2colorthresh [-help]
#
# OPTIONS:
#
# There are no options
#
###
#
# NAME: 2COLORTHRESH
#
# PURPOSE: To automatically thresholds an image to binary (b/w) format
# using an adaptive spatial subdivision color reduction technique.
#
# DESCRIPTION: 2COLORTHRESH automatically thresholds an image to binary
# (b/w) format using an adaptive spatial subdivision color reduction
# technique. This is the -colors IM operator as implemented with slight
# modification from Anthony's Examples at
# http://www.imagemagick.org/Usage/quantize/#two_color
# For algorithm details, see http://www.imagemagick.org/script/quantize.php
#
# OPTIONS:
#
# There are no options.
#
# NOTE: It is highly recommended that the output not be specified
# as a JPG image as that will cause compression and potentially a
# non-binary (i.e. a graylevel) result. GIF is the recommended
# output format.
#
# 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 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 2 ]
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
;;
-) # 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
[ "$outfile" = "" ] && errMsg "NO OUTPUT FILE SPECIFIED"
tmpA1="$dir/2colorsthresh_1_$$.mpc"
tmpA2="$dir/2colorsthresh_1_$$.cache"
trap "rm -f $tmpA1 $tmpA2; exit 0" 0
trap "rm -f $tmpA1 $tmpA2; exit 1" 1 2 3 15
if convert -quiet "$infile" +repage "$tmpA1"
then
: ' do nothing '
else
errMsg "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAG ZERO SIZE ---"
fi
# process image
convert $tmpA1 +dither -colors 2 -colorspace gray -contrast-stretch 0 "$outfile"
exit 0
|
