# !/bin/bash

# Cuts an image into tiles suitable for use with Google Maps.
#
# Copyright (C) 2006-2007 Ian C. Stevens (http://crazedmonkey.com/)
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

usage="Usage: googletilecutter.sh [-1kqh] [-p x,y] [-r tile prefix] 
                           -z zoom -o top-left-zoom -t x,y file

This script cuts an image into tiles suitable for use with Google Maps.  The
tiles are produced from the given file for the given zoom and calculated based
on the coordinates of the top-left tile at a possibly higher zoom.  To tile
files for various zoom levels, one only need change the zoom as specified by
-z.

Tiles follow the naming convention of zAxByC.png, where A, B and C are the zoom
level and the x and y coordinates of that tile, respectively.

    -z zoom     The map zoom level the given file represents.
    -o zoom     The map zoom level for the top-left tile as given by -t. 
    -t x,y      The x and y coordinates of the top-left tile for
                the zoom level specified by -o.
    -p x,y      The x and y padding from the left and top.  Defaults to 0,0.
    -r prefix   Prefix for each tile.  By default, no prefix is added.
    -1          Specifies that version 1 zoom levels should be used.  That 
                is, the zoom level decreases to 1, the most detailed level.
                By default version 2 zoom levels are used.
    -k          Keep empty transparent tiles.  By default, empty transparent
                tiles are deleted.
    -q          Quiet mode.  Suppress all output.
    -h          Display the help message.

This script requires ImageMagick for image manipulation and either advpng or
pngcrush for PNG compression.

Googletilecutter, Copyright (C) 2006-7 Ian C. Stevens (http://crazedmonkey.com)
This software comes with ABSOLUTELY NO WARRANTY. This is free software, and you
are welcome to redistribute it under certain conditions.
"

zoom=""
orgZoom=""
topX=""
topY=""
file=""
version=2
padX=0
padY=0
prefix=""
keepEmpty=0
quiet=0
while getopts ":z:o:t:f:p:r:1kqh" options; do
  case $options in
    z ) zoom=$OPTARG;;
    o ) orgZoom=$OPTARG;;
    t ) topX=`expr "$OPTARG" : '\(.*\),'`
        topY=`expr "$OPTARG" : '.*,\(.*\)'`;;
    p ) padX=`expr "$OPTARG" : '\(.*\),'`
        padY=`expr "$OPTARG" : '.*,\(.*\)'`;;
    r ) prefix="$OPTARG";;
    1 ) version=1;;
    k ) keepEmpty=1;;
    q ) quiet=1;;
    h ) echo -e "$usage"
        exit 1;;
    * ) echo -e "$usage"
        exit 1;;
  esac
done

if [ "$zoom" == "" -o "$orgZoom" == "" -o "$topX" == "" -o "$topY" == "" ]; then
    echo "Missing options"
    echo -n "$usage"
    exit 1
fi

shift $((OPTIND-1)) 
file=$1
if [ "$file" == "" ]; then
    echo "No file specified"
    echo -n "$usage"
    exit 1
fi

# @todo check that zoom levels and coordinates match usage.
if [ $version -eq 1 -a $zoom -gt $orgZoom ]; then
    echo -e "Version 1 zoom level specified.  Zoom Level specified by -z should be less than\nor equal than that specified by -o."
    exit 1
elif [ $version -eq 2 -a $zoom -lt $orgZoom ]; then
    echo -e "Version 2 zoom level specified.  Zoom Level specified by -z should be greater\nthan or equal than that specified by -o."
    exit 1
fi


# check for existence of advpng or pngcrush for compression
compress=""
if [ `which advpng` ]; then
    if [ $quiet -eq 0 ]; then
        echo "Using advpng for compression."
    fi
    compress="advpng"
elif [ `which pngcrush` ]; then
    if [ $quiet -eq 0 ]; then
        echo "Using pngcrush for compression."
    fi
    compress="pngcrush"
else
    if [ $quiet -eq 0 ]; then
        echo "Advpng or pngcrush not found.  Using no PNG compression."
    fi
    compress=""
fi

# v2 increases zoom level, v1 decreases.
if [ $version -eq 2 ]; then
    zoomDiff=$(($zoom - $orgZoom))
else
    zoomDiff=$(($orgZoom - $zoom))
fi
power=`echo | awk "{print 2^$zoomDiff}"`

# pad image to tile size
if [ $quiet -eq 0 ]; then
    echo "Padding image ..."
fi
dim=`identify "$file" | sed -e "s/.* \([0-9]*x[0-9]*\) .*/\1/"`

padX=$(($padX*$power))
padY=$(($padY*$power))
width=$((`echo $dim | sed -e "s/x.*//"`+$padX))
tileWidth=$(($width / 256 + 1))
height=$((`echo $dim | sed -e "s/.*x//"`+$padY))
tileHeight=$(($height / 256 + 1))

temp=`mktemp -t map-XXXXXX`
extraWidth=$((tileWidth*256 - $width))
extraHeight=$((tileHeight*256 - $height))
convert "$file" -bordercolor none -border ${padX}x${padY} -crop ${width}x${height}+0+0 +repage -bordercolor none -border ${extraWidth}x${extraHeight} -crop +$extraWidth+$extraHeight +repage $temp


# tile
if [ $quiet -eq 0 ]; then
    echo "Generating tiles ..."
fi
# pad image to tile size
tempPrefix=$temp-tile
convert $temp -crop 256x256 +repage png32:$tempPrefix

rm $temp

# renumber
if [ $quiet -eq 0 ]; then
    echo "Renumbering and compressing tiles ..."
fi

x=$(($topX * $power))
y=$(($topY * $power))

#adjust
topX=$x

files=`ls $tempPrefix* | wc -l`

for ((i=0; i<files; i++)) do
    tile=$tempPrefix-$i
    newTile=${prefix}z${zoom}x${x}y${y}.png

    # delete if empty
    if [ $keepEmpty -eq 0 ]; then
        identity=`identify -verbose $tile`
        colors=`echo -e "$identity" | sed -ne "s/.*Colors: //p"`
        alpha=`echo -e "$identity" | sed -ne "s/.*Alpha: \((.*)\).*/\1/p" `
        numAlpha=`echo -e "$identity" | sed -ne "s/ *\([0-9][0-9]*\):.*$alpha.*/\1/p"`
        if [ "$alpha" != "" -a "$colors" == "1" -a "$numAlpha" != "0" ]; then 
            if [ $quiet -eq 0 ]; then
                echo "Discarding empty tile: $newTile"
            fi
            rm $tile
        fi
    fi

    # compress and renumber
    if [ -a $tile ]; then
        if [ $quiet -eq 0 ]; then
            echo -n "Compressing $newTile ... "
        fi

        if [ $compress == "advpng" ]; then
            reduction=`advpng -4 -z $tile | sed -ne "s/.* \([0-9]*\)% .*/\1/p"`
            reduction=$((100-$reduction))
        elif [ $compress == "pngcrush" ]; then
            crushout=`mktemp`
            reduction=`pngcrush -brute $tile $crushout | sed -ne "s/.*(\([0-9\.]*\)%.*/\1/p"`
            if [ -f $crushout ]; then
                mv $crushout $tile
            else
                rm $crushout
            fi
        fi

        if [ $quiet -eq 0 ]; then
            if [ "$reduction" == "" ]; then
                reduction=0
            fi
            echo "$reduction%"
        fi

        mv $tile "$newTile"
    fi

    if [[ $(($(($i+1)) % $tileWidth)) -eq 0 ]]; then
        x=$topX
        y=$(($y+1))
    else
        x=$(($x+1)) 
    fi

done