Convert PDF slides to a "sketchy" version

Sometimes, to make your slide decks "fun", you will want to convert them to look like drawing slides.

A simple way to do it is to use imagemagick. The algorithm is super simple:

1. Put your pdf in an empty folder and name it slides.pdf
2. Convert each slide/page in a jpeg image
3. Apply some effect to each image and output it in a sketch_xxxx.jpg file
4. Recombine all sketch_*.jpg in a PDF file named sketch.pdf

Here is what it looks like in a bash script:

# /bin/sh

# 1. convert in jpg
echo "Converting PDF in images"
convert -density 300 slides.pdf slide_%04d.jpg

#2. convert jpg in sketchy jpg
echo "Sketifying the images"
for i in slide_*.jpg; do
  convert $i -colorspace gray \( +clone -blur 0x2 \) +swap -compose divide -composite -linear-stretch 5%x0% $(echo $i | sed 's/slide/sketch/')
done

# 3. convert back in pdf
echo "Creating sketch.pdf"
convert sketch_*.jpg -quality 100 sketch.pdf

Now make this script executable and run it from the folder you created in step 1. and it will create a sketch.pdf file containing your "sketch" deck!

Here is a very simple example quickly done with LibreOffice:

Have fun folks :)