Crop and rotate scaned pages

Prepare4djvu.sh

#!/bin/bash

WIDTH="2880";
HEIGHT="1868";
SHIFT_X="880";
SHIFT_Y="608";
ORIENT="left";

# If right page - first, insert "1", otherwise "0"
RIGHT_FIRST="1";
let "LEFT_ADDITION = RIGHT_FIRST";
let "RIGHT_ADDITION = 1 - RIGHT_FIRST";

if [ "$ORIENT" = "left" ]; then
    DEGREES="-90";
    ADDITION=$LEFT_ADDITION;
else
    DEGREES="+90";
    ADDITION=$RIGHT_ADDITION;
fi

mkdir croped;
for i in IMG_*.JPG; do 
    convert -crop "$WIDTH"x"$HEIGHT"+"$SHIFT_X"+"$SHIFT_Y" -rotate "$DEGREES" -threshold 50% $i croped/$i; 
done

mkdir ../sorted;
let "pagen = 0";
for i in croped/IMG_*.JPG; do 
    let "page = pagen + ADDITION";
    printf -v page "%05d" $page;
    mv $i ../sorted/page-"$page".jpg;
    let "pagen += 2";
done
rm -fr croped;