@seminar/cli

The seminar command presents and previews Seminar decks, and saves built decks as PDFs. It runs the decks in an app of its own, made with Electron. Requires Node.js 24 or newer.

Projects created with npm create seminar already have it, with npm run present, and npm run pdf if you chose PDFs. To add it to other projects:

npm install --save-dev @seminar/cli

Presenting

seminar present                       # build the deck of the project
seminar present decks/talk.deck.mdx   # build another deck
seminar present dist/talk.html        # a deck built already
seminar present dist                  # one of the decks built in dist/

seminar present builds the deck with vite build in the closest directory with a Vite config, leaving out the other decks and pages of the project, and presents it without touching dist/. It builds into node_modules/.cache/seminar/present/, and removes the build when the presentation ends, or when it is stopped, e.g., with Ctrl+C. Without a path, it builds the deck in the root of the Vite project, e.g., decks/. If there are several decks, it asks which one to present. The deck opens in a window, and asks right away which screen should show the slides, as if you pressed P. Unlike a browser, it doesn't ask for permissions first. Once you stop presenting, or cancel choosing the screen, it quits, unless you give it --no-quit-at-end.

On Wayland, browsers can't choose the screen of a window, so seminar present asks the compositor instead. This works with:

• Sway, and other compositors with the wlr foreign toplevel management protocol,
• COSMIC,
• KDE Plasma,
• GNOME, with the Window Calls extension.

With other compositors, move the window of the slides to the screen of the audience, and click it to go full screen.

Previewing

seminar preview                       # the deck of the project
seminar preview decks/talk.deck.mdx   # another deck

seminar preview chooses the deck like seminar present, but serves it with the dev server of Vite instead of building it, and opens it in the same app, which updates the deck as you edit it. The dev server prints the build errors, and the errors and warnings of the page. The title of its window says that it's a preview, and it doesn't start presenting until you press P, which then works like in seminar present, also on Wayland.

With --present, it starts presenting right away, and quits once you stop, like seminar present. With --no-quit-at-end, it stays open instead. --quit-at-end makes it start presenting right away and quit at the end, too.

seminar preview --url <url> previews a page of a dev server that is already running, like that of seminar dev, which prints the errors of the page.

Serving decks

seminar dev runs the dev server of Vite for all decks of the project on a free port, without showing them, and prints its address. The VS Code extension runs it, so that previews of decks can share a dev server.

The server only listens on the local machine. With --allow-any-host, it also answers requests for other host names, as forwarded ports may need. This turns off the protection of Vite against DNS rebinding, which lets other websites read the dev server.

Saving PDFs

seminar pdf saves each deck in dist/ as a PDF next to it, like dist/index.pdf. Build the decks first, e.g., in a script of your package.json:

"pdf": "vite build && seminar pdf"

The options match the Print dialog of the decks:

| Option | What it does | | -------------------------------- | -------------------------------------------- | | --layout <slides\|notes\|grid> | Slides, slides with notes, or several slides | | --per-sheet <2\|4\|6> | Slides on each sheet of the grid layout | | --every-step | A page for every step | | --spares | Include spare slides | | --no-headers | Leave out headers and footers of handouts | | --paper <size> | Paper of handouts, like A4 or Letter | | --out-dir <dir> | Where to save the PDFs |

To save several layouts at once, separate them with commas, like --layout slides,notes,grid --per-sheet 4,6. The PDF of the slides has the name of the deck. Handouts add their layout to it, like dist/index-notes.pdf and dist/index-4up.pdf.

The PDFs keep the title, authors, description, and keywords of the deck. Their outline is the table of contents of the deck, or the titles of its slides. With one slide on each sheet, the page numbers are the slide numbers.

Electron

The app is made with Electron. The first time you use it, seminar downloads Electron into the cache directory of your user account. To download it ahead of time, e.g., before a talk or in a step of continuous integration, run seminar install-electron.

| Environment variable | What it sets | | -------------------- | -------------------------------------------- | | SEMINAR_CACHE_DIR | The cache directory, e.g., to cache it in CI | | SEMINAR_ELECTRON | The executable of an Electron to run instead |