generate-pdfs

name	generate-pdfs
description	Generate PDF exports for the langchain4j-cdi-lab-2026 presentation project. Use this skill whenever the user asks to produce, export, or generate PDFs from any of the project documents: README.md, workshop/index.html, introduction/index.html, or slides/index.html. Accepts arguments: readme, workshop, introduction, slides, or all (default).

generate-pdfs

Generates PDF exports for all project documents using the correct technique for each file type.

Usage

Run the bundled script from the project root:

node <skill_dir>/scripts/generate_pdfs.mjs [readme|workshop|introduction|slides|all]

• No argument / all: generates all four PDFs
• readme: README.md → README.pdf
• workshop: workshop/index.html → workshop.pdf
• introduction: introduction/index.html → introduction.pdf
• slides: slides/index.html → slides.pdf

Output files land in the project root directory.

Prerequisites

Chrome must be installed (used by both md-to-pdf and Puppeteer):

• Expected at /usr/bin/google-chrome (already present on this machine)

Puppeteer must be installed at /tmp. Install once if missing:

cd /tmp && PUPPETEER_SKIP_DOWNLOAD=true npm install puppeteer

PUPPETEER_SKIP_DOWNLOAD=true skips downloading a bundled Chrome (we use the system one). The script auto-detects puppeteer at /tmp/node_modules/puppeteer and falls back to trying a global import.

Techniques — why each approach is needed

README → PDF (npx md-to-pdf)

Simple Markdown-to-PDF via md-to-pdf. Uses the system Chrome (passed via --launch-options). The output PDF is written to the same directory as the source file (project root for README.md).

Workshop / Introduction HTML → PDF (Puppeteer)

These are regular HTML pages with a sticky navigation header.

Problem 1 — navigation header repeats on every page. The header uses position: fixed, which the browser repeats on every print page. Fix: inject a print-media CSS rule that overrides position: fixed → position: relative so the header flows naturally at the top of the first page only.

Problem 2 — browser prints URL/date in header and footer. Puppeteer's page.pdf() option displayHeaderFooter: true with an empty headerTemplate and a custom footerTemplate suppresses the browser's default header while still allowing a page-number footer.

Slides → PDF (Puppeteer + Reveal.js interception)

Reveal.js generates one PDF page per animation fragment by default, causing 3–6× page duplication (e.g. 153 pages instead of 52).

Problem: pdfSeparateFragments: false must be set before Reveal.initialize() is called. Calling Reveal.configure() after init has no effect on PDF page generation.

Fix: page.evaluateOnNewDocument() intercepts the window.Reveal property assignment (via Object.defineProperty) before any scripts run, wrapping initialize() to inject pdfSeparateFragments: false into whatever config the page passes.

The slides are loaded with the ?print-pdf query string, which activates Reveal.js's print layout mode.