convert.sh

#!/bin/bash

#
# Usage
#
#   - Take screenshot files and put them into a directory. You can't put
#     unrelated file into the directory.
#   - Then run "bash convert.sh <DIRECTORY_PATH>"
#
# Notes:
#
#   - You need some image converter tools (convert, pdfcrop, gs)
#   - Pages are orderer in timestamp order, so you should take screenshot
#     in page order.
#

TARGETDIR=$1
SIZESPEC=$2

[ ! "$SIZESPEC" ] && SIZESPEC=1710x2158+1064+2

[ ! -d "$TARGETDIR" ] && echo "TARGETDIR not found." && exit 1

[ "$DEBUG" ] && set -x

if which convert > /dev/null ; then
	echo "command 'convert' not found"
	exit 1
fi

if which pdfcrop > /dev/null ; then
	echo "command 'pdfcrop' not found"
	exit 1
fi

if which gs > /dev/null ; then
	echo "command 'gs' not found"
	exit 1
fi

cd $TARGETDIR

rm tmp_*

NR_PAGES=$(ls -1 | grep png$ | grep -v tmp_ | wc -l)

if [ "$NR_PAGES" -eq 0 ] ; then
	echo "no png files found"
	exit 1
fi

i=1
files=

for line in $(ls -1tr | grep png$ | grep -v tmp_) ; do
	cp "$line" tmp_$i.png
	convert -crop $SIZESPEC "$line" tmp_$i.png
	files="$files tmp_$i.png"
	i=$[i+1]
done
convert $files tmp_output1.pdf || exit 1
pdfcrop --margins '0 0 0 0' tmp_output1.pdf tmp_output2.pdf || exit 1
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dGrayImageResolution=72 -dMonoImageResolution=72 -dColorImageResolution=72 -dPDFSETTINGS=/ebook -dNOPAUSE -dQUIET -dBATCH -sOutputFile=tmp_output3.pdf tmp_output2.pdf || exit 1
mv tmp_output3.pdf output.pdf
rm tmp_*