#!/bin/sh

############################################################################
#
# MODULE:	i.landsat.rgb
#
# AUTHOR(S):	Markus Neteler. <neteler itc it>
#		Hamish Bowman, scripting enhancements
#
# PURPOSE:      create pretty LANDSAT RGBs: the trick is to remove outliers 
#               using percentiles (area under the histogram curve)
#               Needs GRASS 6.1-CVS.
#
# COPYRIGHT:	(C) 2006 by the GRASS Development Team
#
#		This program is free software under the GNU General Public
#		License (>=v2). Read the file COPYING that comes with GRASS
#		for details.
#
# TODO: implement better brightness control
#############################################################################

#%Module
#%  description: Auto-balancing of colors for LANDSAT images
#%  keywords: raster, imagery, colors
#%End
#%option
#% key: red
#% type: string
#% gisprompt: old,cell,raster
#% description: LANDSAT red channel
#% required : yes
#%end
#%option
#% key: green
#% type: string
#% gisprompt: old,cell,raster
#% description: LANDSAT green channel
#% required : yes
#%end
#%option
#% key: blue
#% type: string
#% gisprompt: old,cell,raster
#% description: LANDSAT blue channel
#% required : yes
#%end
#%option
#% key: strength
#% type: integer
#% description: Cropping intensity (upper brightness level)
#% options: 0-100
#% answer : 98
#% required : no
#%end
#%flag
#% key: f
#% description: Extend colors to full range of data on each channel
#%end
#%flag
#% key: p
#% description: Preserve relative colors, adjust brightness only
#%end
#%flag
#% key: r
#% description: Reset to standard color range
#%end


if [ -z "$GISBASE" ] ; then
 echo "You must be in GRASS GIS to run this program." >&2
 exit 1
fi

if [ "$1" != "@ARGS_PARSED@" ] ; then
  exec g.parser "$0" "$@"
fi

# setting environment, so that awk works properly in all languages (unused?)
unset LC_ALL
LC_NUMERIC=C
export LC_NUMERIC

PROG=`basename $0`

BLUE="$GIS_OPT_BLUE"
GREEN="$GIS_OPT_GREEN"
RED="$GIS_OPT_RED"

# 90 or 98? MAX value controls brightness
# think of percent (0-100), must be positive or 0
# must be more than "2" ?
BRIGHTNESS="$GIS_OPT_STRENGTH"


if [ 1 -eq $GIS_FLAG_F ] ; then
   for i in $RED $GREEN $BLUE ; do
      r.colors $i col=grey
   done
   exit 0
fi
if [ 1 -eq $GIS_FLAG_R ] ; then
   for i in $RED $GREEN $BLUE ; do
      r.colors $i col=rules << EOF
	0 black
	255 white
EOF
   done
   exit 0
fi

if [ 0 -eq $GIS_FLAG_P ] ; then
   for i in $RED $GREEN $BLUE ; do
      echo "Processing <$i> .."
      MIN=`r.univar.sh -e $i per=2  | grep Percentile | cut -d' ' -f3`
      MAX=`r.univar.sh -e $i per=$BRIGHTNESS | grep Percentile | cut -d' ' -f3`
      #echo "[$i]:  min=$MIN   max=$MAX"
      r.colors $i col=rules << EOF
	0% black
	$MIN black
	$MAX white
	100% white
EOF
      done
else
   ALL_MAX=0
   ALL_MIN=255
   for i in $RED $GREEN $BLUE ; do
      echo "Processing <$i> .."
      MIN=`r.univar.sh -e $i per=2  | grep Percentile | cut -d' ' -f3`
      MAX=`r.univar.sh -e $i per=$BRIGHTNESS | grep Percentile | cut -d' ' -f3`
      #echo "[$i]:  min=$MIN   max=$MAX"
      if [ $MAX -gt $ALL_MAX ] ; then
	ALL_MAX=$MAX
      fi
      if [ $MIN -lt $ALL_MIN ] ; then
	ALL_MIN=$MIN
      fi
   done
   #echo "all_min=$ALL_MIN   all_max=$ALL_MAX"
   for i in $RED $GREEN $BLUE ; do
      r.colors $i col=rules << EOF
	0% black
	$ALL_MIN black
	$ALL_MAX white
	100% white
EOF
   done
fi

exit 0