Rendering pipeline¶

Why does conversion go through HTML and a browser?

md-to-pdf uses an HTML-first rendering pipeline because Markdown, Mermaid, CSS, and PDF layout all meet naturally in a browser.

For this command:

md-to-pdf guide.md --output guide.pdf

the pipeline is:

1. Parse Markdown with pulldown-cmark.
2. Rewrite fenced Mermaid code blocks into Mermaid containers.
3. Generate a print-focused HTML document.
4. Launch Chrome, Chromium, or Edge with the Chrome DevTools Protocol.
5. Wait for Mermaid to report ready, or fail on error.
6. Ask the browser for PDF bytes with Page.printToPDF.

The Rust code owns orchestration, paths, escaping, and CLI behavior. The browser owns JavaScript execution, diagram layout, CSS layout, and PDF generation.

Related tasks: Debug rendering and Choose a browser.