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Ask HN: Where are the good Markdown to PDF tools (that meet these requirements)?

41 points by SamCoding ↗ HN
I'm trying to convert a very large Markdown file (a couple hundred pages) to PDF.

It contains lots of code in code blocks and has a table of contents at the start with internal links to later pages.

I've tried lots of different Markdown-PDF converters like md2pdf and Pandoc, even trying converting it through LaTeX first, however none of them produce working internal PDF links, have effective syntax highlighting for HTML, CSS, JavaScript and Python, and wrap code to fit it on the page.

I have a very long regular expression (email validation of course) that doesn't fit on one line but no solutions I have found properly break the lines on page overflow.

What tools does everyone recommend?

57 comments

[ 3.3 ms ] story [ 146 ms ] thread
fforflo
Does converting to HTML first and then to PDF help?
deanebarker
This is what I have done for a couple of books I wrote in Markdown (https://deanebarker.net/books/).

Convert to HTML, then use Prince (https://www.princexml.com/) to style and convert to PDF.

tnt128
Their licenses are pretty expensive. Any good free open source alternatives?
jessekv
If it looks correct in a browser, then chromium + playwright.
flowerthoughts
I don't know what the scope of this is, but https://pagedjs.org/ is Javascript that does pagination and page margin styling. It's essentially a polyfill for CSS Paged Media: https://www.w3.org/TR/css-page-3/

Pretty nice to work with, if you can run JS. (The rest is just Puppeteer to print. Though I couldn't use their command line tool, because it force-injects paged.js, and it didn't play well with the Preact components for previewing I had made.)

deanebarker
I've only ever used a free version? I've never paid for it. I think it's free for personal projects? Or at least it was...

Edit: I see it's $495 now. I don't think it was priced when I used it, but it's been 4-5 years.

ludsan
I'm surprised Pandoc didn't fit the bill. It's quite configurable with fenced attributes.

I switched from using MD-->(Pandoc-->(latex))--> PDF to using MD-->(Pandoc-->(typst))--> PDF.

arcanemachiner
I read quite a few people gushing about Pandoc in a similar thread. I have to look into it, as I have similar needs as the OP.
WolfOliver
I would love to read your feedback how it works with MonsterWriter.

1. Download the app [01] 2. Create a new empty document 3. Insert a markdown section type 4. past your markdown code into the markdown section 5. click on "Preview & Export" 6. Configure your PDF

I'm the creator of MonsterWriter. For complex markdown it probably has some shortcomings but I would love to hear what is missing for your use case.

[01] https://www.monsterwriter.com/

SamCoding
Does it support code blocks for Python, JS, HTML and CSS? Also my Markdown is auto-generated by a script of mine. Can I paste Markdown directly into y our platform?
Yoric
Have you tried mdbooks?
geor9e
I think you're overcomplicating it. I assume you created this markdown file and I assume you have a preview render that shows it the way you like it to be shown. So just hit the print button, and in the print dialog select save as PDF.
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npodbielski
You are right if OP want to do this manually. If not I guess it is much more complicated, you would need some tool that allows you to print rendered markdown. Add one more step: convert print to PDF and effectively you have tool to convert markdown to PDF.
milch
I do this with Chrome for my resume. Write it in Markdown, convert to HTML using Pandoc and then print it to PDF using Chrome.

Google\ Chrome --no-sandbox --headless --print-to-pdf-no-header --no-pdf-header-footer --enable-logging=stderr --log-level=2 --in-process-gpu --disable-gpu --print-to-pdf=resume.pdf "file://path/to/resume.html"

npodbielski
Pretty neat. Did not thought that it is possible. Thanks.
gloxkiqcza
I’m not OP but e.g. VS Code markdown preview (which works great) doesn’t offer printing.
Yoric
Random idea: how hard would it be to convert your markdown to typst?
martylamb
It's not marketed as a markdown-to-pdf tool, but I've found that Obsidian (https://obsidian.md) does an excellent job. Just create a new "vault", paste your markdown into a new note, and export to PDF.
SamCoding
I love Obsidian too, however I found that internal links didn't work when exporting it. Do you know what format works? My internal links work in the Obsidian preview but not in the PDF export.
_diyar
How should the internal links work when converting into a PDF? They are obviously intended to enable a wiki-like structure in your notes, but I don't see a ways they could work upon export.
martylamb
Do you mean internal links within the page, or within your vault? I can't say I've relied on either in a pdf export, but I would expect the former to work and the latter to fail. I suppose links to other notes in your vault could use the obsidian:// protocol but that would be weird to say the least.
tikhonj
I worked on a 500+ page book[1] in Pandoc that included a bunch of code samples, math, a table of contents with working links and an index. (In hindsight, I wish we had thought about the index from the beginning rather than adding it after the fact.)

What worked well for me: Pandoc with a custom LaTeX template, and a decent amount of inline LaTeX to handle edge cases. We had a LaTeX theme to use from our publisher, but we also needed our own totally separate theme for the free version version of the book.

For one-off things like really long code lines, I found it best to manually figure out how to handle them. Sometimes there was a bit of TeX magic but, more often, I just rewrote or reorganized the code. I see the presentation and structure of code and math snippets as an integral part of how I'm communicating the underlying ideas, so manually changing things around to read better was fundamentally no different from going back and editing prose.

Unfortunately, this also means that the process was relatively hands-on. If you need something ≈completed automated, I expect Pandoc → LaTeX is going to fall a bit short. Edge cases need manual intervention, and it's easy for formatting errors to sneak in—the free version of our book has some formatting mistakes like code bleeding into the margin because I ran out of energy to fix all of them!

[1]: https://github.com/TikhonJelvis/RL-book

netbioserror
Typora is the best I've used. It's a GUI, but it's pretty fantastic for a GUI Markdown editor (especially an Electron one), and its PDF export is consistent and customizable with styles. Includes a few good ones out of the box. Plus an automated TOC.
Oras
weasyprint worked well for me. I'm using it in a service to export resumes.

Keep in mind that you'll need to install custom fonts if you're using languages other than English.

solardev
Have you explored the AST (abstract syntax tree) tools yet, like Mdast and the related remark and micromark?

https://github.com/syntax-tree/mdast-util-from-markdown

It might work better if you parse it into an intermediary Mdast format first, do whatever processing you need to implement "pages" (not a part of any Markdown dialect I'm familiar with?" but it shouldn't be hard to write a custom parser for that in Mdast), output that to HTML (via https://github.com/syntax-tree/mdast-util-to-hast) and THEN convert the HTML to PDF.

The AST tools basically give you structured JSON that's much easier to work with programmatically than raw Markdown. Then you can render that semantic JSON into HTML or other outputs.

mncharity
I wonder how the Mdast and pandoc ASTs compare?

I did a customized-MD pipeline which normalized to pandoc (extra features got encoded to pass through pandoc), obtained the pandoc JSON ast, and emitted html/latex/etc using Julia pattern matching. The code was small, and the yak shave and husbandry was worth escaping the struggle with sea of crufty candidate tools, each with assorted one-chosen-point in a high-dimensional design space, and missing features, misfeatures, gotchas, and mazes ("maybe if I combine this unmaintained plugin with that one and add a postprocess massage step over there and then maybe..." - blech).

solardev
I am not familiar with Pandoc, but it looks like a command-line tool that can do the same things? (Edit: I suspect this is probably one of those situations where different industries/domains end up developing similar tools in different ecosystems... Pandoc probably makes sense in academia, LaTex workflows, etc.? Mdast is used for web apps. I can see both realms wanting to do Markdown conversions, so I'm not surprised to see similar tools available in both. I'm a web dev, so only familiar with Mdast.)

My guess is that either toolchain could do the job... maybe just depends on personal preference whether someone prefers to pipe together command-line tools in a bash script, vs making use of the npm ecosystem (mdast is all in JS).

Maybe the popularity of JS & npm means there are available mdast plugins & third party packages that can help with whatever niche transformation you might need, and custom node rendering is just a lambda away. It's all in JS for a seamless experience, and there is no separate DSL to learn (just some basic helper functions).

That might be harder to do in Pandoc... (might need a custom Lua filter or another language like your Julia pattern matching?)

As for effectiveness... it probably just depends on the particular implementer :) I'd trust a grizzled old *NIX sysadmin type over your typical bootcamp JS programmer any day, but also... the JS ecosystem is pretty mature and powerful now, and Mdast is pretty amazing. At work we use it to build one of the most important parts of our app, and its power and flexibility never cease to amaze me.

mncharity
Let's see. So there are parsers in various languages, parsing various MD dialects, with varied internal representations, and surrounding ecosystems. And there are attempts at more turnkey document processing systems, often with a more extended dialect, and some collection of feature plugins. Often you can write pipeline AST filters in the given language, and sometimes get out an AST as JSON, and sometimes reinject JSON AST (allowing writing a filter in any language). Which leaves questions like: what dialect is the parser; is that extensible; how robustly correct is it; how clean and easily used and fragile is the AST; how well do the plugins/ecosystem already support your needed features. That AST one, I think of as a big deal, and hard to get a handle on. Aside from manipulation pragmatics, the asts resulting from parsing can get richly creative in quirkiness, that you then may need to regularize.

So I guess two main observations. On build-vs-buy for backend features, given the breadth of possible "we want it like this, and not that", if one can easily play with ASTs, I was surprised by how quickly reinventing the wheel became a plausible call. Possibly skimming existing backend code for insight and templates, but mostly not using it (aka struggling to configure it to give you "this and not that"). The other observation, is once you have ast and don't care about existing backends, your choice of parser and backend language/ecosystem decouple. One might use `pandoc --to=json` and then JS generic-ast tooling to emit HTML.

For parsing, a glance suggests Mdast emphasizes CommonMark and Github-flavored dialects. Pandoc-flavored MD is a bit broader.[1] My fuzzy recollection is I chose a pandoc parse for that, and an expectation of robustness ("it's haskell, and popular"), despite the then less that wonderful docs. IIRC, the resulting asts were fine. For backend, I wanted simple and concise to minimize burden, thus pattern matching (IIRC, most node types ended up a line or two), and chose road-less-traveled Julia for off-topic reasons (was thinking of using Julia for a compiler backend).

Thanks for your thoughts on Mdast - I'm tempted to play with it.

[1] https://garrettgman.github.io/rmarkdown/authoring_pandoc_mar...

jppope
typora.io is what I use
countrymile
Quarto is worth looking at. Might not be able to solve you regex issue though.
amgreg
If you’re on a Mac or iOS you could try creating a Shortcut where you input Markdown, convert to rich text, then output as a PDF. I use Shortcuts regularly. It’s pretty easy to set up. I haven’t tried it on something as larger as 500 pages, though. YMMV
SamCoding
I'm on Windows (with WSL) so unfortunately I can't.
westurner
MyST-MD transforms to LaTeX or HTML, which are transformable to (PostScript and then) PDF. With LaTeX it's possible to exactly typeset.

Sphinx and jupyter-book support MyST Markdown.

PDF Tables of Contents with links to headings or page numbers are possible with MyST and RestructuredText.

Ancapistani
I’ve not used it for very large documents, but I’ve been very happy with the fidelity of conversion using Marked 2 (https://marked2app.com)

I believe it’s Mac only. I use it sometimes when I’m creating PDFs from my personal documentation to share more publicly, which I keep in Markdown and deploy on Gitlab Pages as a static site.

misterspaceman
Have you already tried converting it in Google Docs?
marcrosoft
Render to html and then use webkit2pdf which will give you a pdf that looks exactly like the html shown in chrome. This is a million times easier than working with PDF libraries
i_am_proteus
Quarto should "just work" for this. There's an option to wrap code blocks.
pronoiac
I think Pandoc and Calibre could work for you.

I've worked on PAIP, Paradigms of Artificial Intelligence Programming, and I might be able to help you a bit. It's around 1k pages long. I used Pandoc to generate an epub file, and then Calibre to turn that into a PDF file. I just tried using Pandoc to generate the PDF file directly, and it/LaTeX choked on some Unicode characters.

For internal ebook links, there's a Lua script. You'll have to keep anchors unique across the book for this:

* good: "chapter1#section1_1" and "chapter2#section2_1"

* bad: a "chapter1#section1" and a "chapter2#section1"

WIP: https://github.com/norvig/paip-lisp/pull/195

For line wrapping of code, there's CSS. I first used it over on "Writing an Operating System in 1,000 Lines"; here's the PR: https://github.com/nuta/operating-system-in-1000-lines/pull/...