#!/bin/sh
# 
# Generate a small clipping at the specifided geometry from an image file.
# Copyright (c) 2018-2019, Hiroyuki Ohsaki.
# All rights reserved.
# 
# $Id: doc-annotate-clip,v 1.2 2019/02/26 06:33:44 ohsaki Exp $
# 

# This code is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY.  No author or distributor
# accepts responsibility to anyone for the consequences of using it
# or for whether it serves any particular purpose or works at all,
# unless he says so in writing.  Refer to the GNU Emacs General Public
# License for full details.
#
# Everyone is granted permission to copy, modify and redistribute
# this code, but only under the conditions described in the
# GNU Emacs General Public License.   A copy of this license is
# supposed to have been given to you along with GNU Emacs so you
# can know your rights and responsibilities.  It should be in a
# file named COPYING.  Among other things, the copyright notice
# and this notice must be preserved on all copies.

# example: doc-annotate-clip page-1.png 0.212 0.342 clip.png

# This program requires /bin/zsh and identify and convert programs
# from ImageMagick (https://www.imagemagick.org/).

if [ $# != 4]; then
    echo "usage: doc-annotate-clip iamge-file x y outfile" 2>&1
    exit 1
fi

infile=$1; shift
rx=$1; shift
ry=$1; shift
outfile=$1; shift

pdf_size=`identify $infile | cut -d' ' -f3`
pdf_width=`echo $pdf_size | cut -dx -f1`
pdf_height=`echo $pdf_size | cut -dx -f2`

# FIXME: clip size should be configurable
clip_w=400
clip_h=`echo $clip_w / 3 | bc`

x=`echo $pdf_width  \* $rx | bc`
y=`echo $pdf_height \* $ry | bc`

x1=`echo $x - $clip_w / 2 | bc`
y1=`echo $y - $clip_h / 2 | bc`

# FIXME: point size should be configurable
rect_x1=`echo $x - 2 | bc`
rect_y1=`echo $y - 2 | bc`
rect_x2=`echo $x + 2 | bc`
rect_y2=`echo $y + 2 | bc`

convert $infile -fill red -draw "rectangle $rect_x1,$rect_y1 $rect_x2,$rect_y2" \
	-crop ${clip_w}x${clip_h}+$x1+$y1 $outfile