pptx-to-md

Converts presentation files (PowerPoint/Impress, or anything else that LibreOffice can read as a presentation) to Beamer-friendly, Pandoc-style markdown.

It's a two part conversion: one script (pptx-to-yaml.py) converts from pptx (or ppt, odp etc) into an intermediate YAML format, then another (yaml-to-md.py) converts the YAML to Pandoc-style markdown.

As a convenience, a Bash wrapper script is provided (converter.sh) which calls both of these, and handles a few other graphics-conversion tasks (such as converting SVG files, which LaTeX can't natively read, to encapsulated PostScript files, which it can).

pptx-to-yaml usage

$ ./pptx-to-yaml.py [--use-server HOST:PORT] INPUT_FILE OUTPUT_FILE IMAGE_DIR

INPUT_FILE is the path to some ppt, pptx or Impress file.

OUTPUT_FILE is the name of the YAML file to be written.

IMAGE_DIR is a directory where images will be extracted to.

It will be created if it doesn't exist.

See soffice-server below for details of what --use-server is for.

PowerPoint features supported

Title text, "outline" text (i.e. bullets) and embedded graphics like JPEGs or PNGs are handled reasonably well. Formatting such as italics, bold or colouring of text is not preserved. Nor are numbered lists - they're converted into bulleted lists.

Embedded "metafiles" (EMF or WMF vector graphics) should get converted to SVG. (And thence to EPS, if you use convert.sh.)

If it finds any tables, drawing shapes (arrows/boxes etc), pptx-to-yaml.py tries to collect them all together and export them as an SVG.

soffice server

pptx-to-yaml.py attempts to start an soffice process and communicate with it over port 2002 on the local host; it's the soffice process that knows how to read and manipulate PowerPoint files.

However, the HOST:PORT arguments can be supplied if you prefer to run your own instance of soffice as a separate process. Which you might want to, since:

a. If you have a lot of files to convert, you can just keep one soffice process running, and re-use it, avoiding the time taken to start a new process for each document.

b. Sometimes pptx-to-yaml.py just doesn't seem to start the soffice process up correctly - I have no idea why.

So you could start the server process using something like the following:

$ xterm -e 'soffice --accept="socket,host=localhost,port=2002;urp;" \
    --norestore --nologo --nodefault --headless' &

... which will open an soffice instance running in its own terminal window; and then specify HOST and PORT to pptx-to-yaml.py.

yaml-to-md usage

$ ./yaml-to-md.py INPUT_FILE OUTPUT_FILE

Just takes an input file and output file.

utility script - convert.sh

usage:

$ ./convert.sh [INPUT_FILE..]

Convenience wrapper around pptx-to-yaml and yaml-to-md. Also converts SVG files to encapsulated PostScript (EPS) for use by LaTeX, and attempts to use Pandoc to create LaTeX and PDF files. (If it fails, that means the .md file needs some tidying, so the PDF file just isn't produced.)

prerequisites

For pptx-to-yaml.py and yaml-to-md.py:

• Python 3.5 or greater
• LibreOffice 5.1.6. On Ubuntu 16.04 (xenial), this can be installed with sudo apt-get install libreoffice.
• python3-uno. On Ubuntu, this can be installed with sudo apt-get install python3-uno.
• pyyaml. Most easily installed with something like pip3 install --user pyyaml.

For convert.sh:

• Requires bash, sed, Inkscape (for converting SVG to EPS) and Pandoc (for converting .md to .tex or .pdf).

idiosyncracies

Exported/graphics files are all referred to by absolute pathname, so if you want to move your generated files around, you'll have to edit any references to them in the YAML/markdown, as appropriate.

Portability

Not at all portable, and not tested on any other platform other than Ubuntu 16.04, nor with any other version of LibreOffice than 5.1.6.

Reporting bugs

You can if you want, but there's no guarantee I'll fix them. The scripts are really just offered as a starting point for anyone else who wants to improve them.

(Un)license

This software is in the public domain. Do with it what you will. If you manage to improve it, it would be nice to hear from you. Try contacting me on Twitter, handle @phlummox.

troubleshooting

can't connect

If you get some error saying pptx-to-yaml.py couldn't connect to the server -- kill any stray soffice process and try again.

If it still fails, possibly add a bigger time.sleep in the script, or just run your own server process.

can't open wmf/emf files in inkscape

Try opening them in lodraw.

Pandoc/LaTeX fails to compile .pdf

Lots of things could have gone wrong. By default, Pandoc uses pdflatex, which will choke on many Unicode symbols. Graphics might not have converted. etc.

The only thing to do is take a look at the original PowerPoint file, and the generated markdown, and see if you can fix whatever went wrong.