#!/bin/sh
#
# View/edit text in a TIFF, PNG, JPEG or GIF file
#

cmd=$(basename $0)
magic=/usr/share/misc/magic-mm
template=~/graphics/images/tifftext/template.txt

bye()
{
    rm -f $tmptext $tmpfile $tmpstamp
    exit $1
}

usage()
{
    echo "usage: $cmd [-v] file" >&2
    exit 1
}

if [ $# -eq 0 ]; then
    vi $template
    exit 0
fi

while getopts ":v" c
do
    case "$c" in
    v)     v_flag=1;;
    :|'?') usage;;
    esac
done
shift $(($OPTIND - 1))
if [ $# -eq 0 ]; then usage; fi

if [ ! -f "$1" ]; then
    echo "$cmd: No such file" >&2; bye 1
fi

tmptext=$(mktemp ~/.$cmd.XXXXXX) || bye 1

ts="$(file -m $magic "$1")"; t="${ts#*: }"
case "$t" in
TIFF\ image\ data*)
    type=tiff
    tiffinfo "$1" | nawk '
    function output(field)
    {
	pos = match($0, /:.*$/)
	value = substr($0, pos + 3, RLENGTH - 4)
	gsub(/\\n/, "\n                ", value)
	printf "%-16s%s\n", field, value
    }
    /^  Artist:/ { output("artist") }
    /^  Document Name:/ { output("documentname") }
    /^  Image Description:/ { output("description") }
    /^  Date & Time:/ { output("datetime") }
    /^  Copyright:/ { output("copyright") }
    /^  Host Computer:/ { output("hostcomputer") }
    /^  Make:/ { output("make") }
    /^  Model:/ { output("model") }
    /^  Software:/ { output("software") }
    ' >$tmptext
    ;;

PNG\ image\ data*)
    type=png
    if [ -n "$v_flag" ]; then
	pngmeta --quiet "$1" | nawk '
	function output()
	{
	    colon = index($0, ":")
	    printf "%-16s%s\n", substr($0, 1, colon - 1), substr($0, colon + 2)
	}
	/^Title: / { output(); next }
	/^Author: / { output(); next }
	/^Description: / { output(); next }
	/^Copyright: / { output(); next }
	/^Creation Time: / { output(); next }
	/^Software: / { output(); next }
	/^Disclaimer: / { output(); next }
	/^Warning: / { output(); next }
	/^Source: / { output(); next }
	/^Comment: / { output(); next }
	{ printf "%16s%s\n", "", $0 }' >$tmptext
    else
	tmpfile=$(mktemp ~/.$cmd.XXXXXX) || bye 1
	pngtopnm -text $tmptext "$1" >$tmpfile || bye 1
    fi
    ;;

JPEG\ image\ data*)
    type=jpeg
    tmpfile=$(mktemp ~/.$cmd.XXXXXX) || bye 1
    rdjpgcom "$1" | nawk '{ r[n++] = $0 }
END { for (i = 0; i < NR - 1; i++) print r[i]
      if (r[NR - 1] != "") print r[NR - 1] }' >$tmptext
    ;;

GIF\ image\ data*)
    type=gif
    gifsicle -I "$1" | nawk '
/^ +comment / { sub(/^ +comment /, ""); gsub(/\\n/, "\n"); r[n++] = $0; next }
END { for (i = 0; i < n; i++) print r[i] }' >$tmptext
    ;;
esac

if [ -n "$v_flag" ]; then
    if [ -s $tmptext ]; then less -C $tmptext; fi
    bye 0
fi

if [ \( "$type" = "tiff" \) -a \( ! -s $tmptext \) ]; then
    cp $template $tmptext || bye 1
fi

tmpstamp=$(mktemp ~/.$cmd.XXXXXX) || bye 1
vi $tmptext || bye 1

if [ $tmptext -nt $tmpstamp ]; then
    case "$type" in
    tiff)
	tiffedit "$1" -T $tmptext
	;;
    png)
	pnmtopng -ztxt $tmptext $tmpfile >"$1" || bye 1
	;;
    jpeg)
	wrjpgcom -replace -cfile $tmptext "$1" >$tmpfile
	mv -f $tmpfile "$1" && chmod go+r "$1"
	;;
    gif)
	gifsicle -b +c -c "$(cat $tmptext)" "$1"
	;;
    esac
fi
bye 0
.