sign-pdf

#!/bin/bash
#set -o xtrace
#############################################################
# SignPDF: A simple way to add a signature image to a pdf at given page under linux.
#          The inserted signature has the same aspect ratio than the original.
#############################################################
# Description:
#
# Written by : Emmanuel Branlard
# Date : April 2012
# Dependencies :  pdftk
# License : Feel free to modify and adapt it
#
# Usage:
#   First argument: pdf file 
#   Second argument: page number where the signature should be put
#   
#
# Example: Add a signature to file "my file.pdf" on page 5:
# ./SignPDF "my file.pdf" 5 "signature.png" 100 300 400 500
#
# Note : You need to edit the SIGNATURE variable below for default signature
#        This script generates a folder where everything takes place
#        The folder is deleted afterwards. See line below:
TMP=tmp-folder-signpdf

if [ $# -ne 7 ]
then
    echo "
Usage: 
    SignPdf <PdfFile> <PageNumber> SignatureFile x1 y2 x2 y2
Example:
    SignPdf \"my file.pdf\" 5 signature.png 100 300 400 500

Look at the source for more informations.
    "
    exit 0
fi
SIGNATURE=$3
x1=$4
y1=$5
x2=$6
y2=$7

echo " -------------- Called with:  -------------- 
File : $1
Page : $2
Signature: $SIGNATURE "


#  set -vx
DIR=`pwd`;
mkdir $TMP
cd $TMP

echo "-------------- Bursting pdf   -----------------"
pdftk "../$1" burst output page_%d.pdf
# convert -page A4 -units PixelsPerInch -density 100 page_$2.pdf page_$2.png
convert -density 100 page_$2.pdf page_$2.png

#echo "-------------- !!! Click on two points defining the signature box -----------------"
#echo "-------------- !!! Don't resize the window - you can move it though -----------------"
#echo "--------------        Press q to exit       -----------------"
##xv -nolimits -D 1 page_$2.png 2> log.log
## cat log.log |grep --colours=none ButtonPress |grep --colours=none mainW
## cat log.log |grep --color=none ButtonPress |grep --color=none mainW |tail -n 2 >buff.log
#cat log.log |grep --color=none ButtonPress |grep --color=none mainW |tail -n 2|cut -c 29- > buff.log
#x1=`awk -F, 'NR==1 {print $1}' buff.log|tr -d -c '[0-9]'`
#y1=`awk -F, 'NR==1 {print $2}' buff.log|tr -d -c '[0-9]'`
#x2=`awk -F, 'NR==2 {print $1}' buff.log|tr -d -c '[0-9]'`
#y2=`awk -F, 'NR==2 {print $2}' buff.log|tr -d -c '[0-9]'`

# dimensions of the rectangle specified by the user
dx=`expr $x2 - $x1`
dy0=`expr $y1 - $y2`

# a flag to see if the user has gone up and down instead of down and up
reverse_flag=0
# checking user input
if [[ $dy0 -lt 0 ]]
then
    reverse_flag=1
    dy0=`expr $y2 - $y1`
fi 
if [[ $dx -lt 0 ]]
then
    buffer=$x2
    x2=$x1
    x1=$buffer
    dx=`expr $x2 - $x1`
fi

cd $DIR
# Signature image dimensions
dxs=`identify -format "%[fx:w]" "$SIGNATURE"|tr -d -c '[0-9]'`
dys=`identify -format "%[fx:h]" "$SIGNATURE"|tr -d -c '[0-9]'`
cd $TMP

# Keeping aspect ratio of the signature
dy=`expr $dx \* $dys / $dxs`

if [[ $reverse_flag -eq 0 ]]
then
    # Here it's tricky either you use the user input $dy0 or $dyA
    y1=`expr $y1 - $dy0`
fi 
# The following because I chose to double the density
# dx=`expr $dx \* 2`
# dy=`expr $dy \* 2`
# y1=`expr $y1 \* 2`
# x1=`expr $x1 \* 2`
# composite -geometry  100x100+$y1+$x1 $SIGNATURE page_$2.png composite.png
echo "-------------- Inserting Signature at lower left corner: +$x1+$y1"

cd $DIR
composite -geometry  "$dx"x"$dy"+$x1+$y1 "$SIGNATURE" $TMP/page_$2.png $TMP/page_$2b.png
convert -density 100 $TMP/page_$2b.png $TMP/page_$2.pdf
pdftk $TMP/page_*.pdf cat output "${1%.pdf}_signed.pdf"


echo "-------------- File ${1%.pdf}_signed.pdf created  ------------- "
echo "-------------- Done -------------"
rm -r $TMP