ODP to Markdown converter — OpenDocument slides

In OpenDocument, a presentation is a sequence of draw:page elements, each one a canvas holding positioned frames of text. It is a drawing format wearing a presentation hat, which is a more honest description of what a slide really is than PowerPoint's placeholder model — and it means the outline you want out of an .odp has to be recovered from frames whose only ordering is where they sit on the page.

Each page contributes its title frame as a line of text, then its outline frame as the bullet list beneath, in the order Impress stores the pages. The title is text and not a Markdown heading — an ODP title frame is a frame with a role, and a role is not a depth, so there is no heading level to assign. Frames that are neither title nor outline still contribute their text, appended after the bullets, so a stray callout box is not silently dropped.

Everything that makes it a presentation rather than a document goes: the frame coordinates, the master pages that supply the background and the footer, and the animation effects. The notes pages are the exception — the text Impress keeps beside each slide is appended to that slide as a blockquote, which is useful when the argument lives in the notes and awkward if the notes were meant for you alone.