Composite thumbnails of multipage pdf into stacked image

Alec Jacobson

April 22, 2013

weblog/

Here's a bash script that takes a multipage pdf and produces a stack of thumbnails with nice shadows: Save this in multipagethumb.sh: #!/bin/bash

# montage -gravity center null: null: 'supplemental_opt.pdf' null: null:
# -thumbnail 128x128 -sharpen 10 -bordercolor white -border 0 -background none
# +polaroid -set label '' -background Transparent -tile x1 -geometry -0+64
# -reverse -flop png:- | convert png:- -flop -trim output.png
if [ $# -lt 2 ]
  then
  echo "Usage:"
  echo "  ./multipagethumb input.pdf output.png"
  exit 1
fi

output="${2%.*}"
## this occassionally gives a concatentation of number of pages number of pages
## times: 10101010101010101010
#n=`identify -format %n $1`
n=`pdftk $1 dump_data | grep NumberOfPages | sed 's/[^0-9]*//'`

# 88+12+30*16 = 580
w="88"
x="30"
y="3"
for p in $(seq 1 $n)
do
  p=`echo "$p-1"|bc`
  echo "convert $1[$p] -flatten -thumbnail ${w}x -bordercolor none -border 0 \( +clone \
    -background none -shadow 80x3+2+2 \) +swap -background none -layers \
    merge +repage  $output-$p.png"
  convert $1[$p] -flatten -thumbnail ${w}x -bordercolor none -border 0 \( +clone \
    -background none -shadow 80x3+2+2 \) +swap -background none -layers \
    merge +repage  $output-$p.png
  if [[ $p == "0" ]]
  then
    echo "convert $output-$p.png $2"
    convert $output-$p.png $2
  else
    echo "convert $output.png -gravity SouthEast -background none -splice ${x}x${y} $output.png"
    convert $output.png -gravity SouthEast -background none -splice ${x}x${y} $output.png
    echo "composite -compose dst-over $output-$p.png $output.png -gravity SouthEast $output.png"
    composite -compose dst-over $output-$p.png $output.png -gravity SouthEast $output.png
  fi
  rm $output-$p.png
done

Then issue:

./multipagethumb.sh input.pdf output.png

Note: You can achieve something similar with the montage and +polaroid command but it was difficult to achieve diagonal stacking and the correct order.