Slice a long image into a PDF of letter-sized pages

pdf-ify.sh

#!/usr/bin/env bash
#
# Slice a long image into a PDF of letter-sized pages.
# Requires ImageMagick.

# Page size
H="11"
W="8.5"

# Input handling
image="$1"
if [ ! $image ]; then echo "usage: $0 image-file"; exit 1; fi
name="$(echo $image | cut -f 1 -d '.')"

# Caluclate dimensions
dims=$(identify -format "%w %h" "$image")
width=$(echo "$dims" | cut -f 1 -d ' ')
height=$(echo "$dims" | cut -f 2 -d ' ')
pages=$(bc <<< "scale=3; ($height/$width)/($H/$W)")
pages_N=$(bc <<< "($pages+0.5)/1-1") # round to integer (sorta), then 1
pageheight=$(bc <<< "$height/$pages")

echo "Pixels Total: ${width}x${height}"
echo "Pages Total:  $pages"
echo "Page height in pixels: $pageheight"

# Slice main image into pages
for x in $(seq 0 $pages_N)
do
	top=$(bc <<< "${pageheight}*${x}")
	convert "$image" -crop "${width}x${pageheight}+0+$top" "$name-$(printf %.2d $x).jpg"
done

# Merge separate pages into single PDF
convert ${name}-*.jpg ${name}.pdf