# PDF Generation for IETF Drafts

## Status

`xml2rfc --pdf` is wired up on this machine. PDFs are generated automatically
as part of `build.sh` in each draft directory.

## How it works

`xml2rfc` is installed via `pipx` in its own venv
(`/home/c/.local/share/pipx/venvs/xml2rfc/`). The `--pdf` switch requires
several extra dependencies that had to be injected into that venv:

```bash
pipx inject xml2rfc "weasyprint<60" pycairo pangocffi
/home/c/.local/share/pipx/venvs/xml2rfc/bin/python -m pip install "pydyf<0.10"
```

Version pins matter:
- `weasyprint 59.x` — xml2rfc's `--pdf` code path calls weasyprint's
  `write_pdf(target, stylesheets=[...], presentational_hints=True)`.
  Newer weasyprint (60+) changes the signature.
- `pydyf <0.10` — weasyprint 59 calls `pydyf.PDF(version, identifier)` with
  two positional args. pydyf 0.10+ removed those.

System libs used via ctypes: `pango`, `pangocairo`, `cairo`, `harfbuzz`
(all already present via Fedora packages).

Fonts: xml2rfc uses Noto + Roboto Mono embedded in the weasyprint output.
Not installed system-wide but weasyprint fonttools handles them.

## Build step (pattern for build.sh)

After the HTML step, add:

```bash
# Step 4: XML -> PDF
echo "Generating PDF output..."
if "$XML2RFC" "$DIR/$DRAFT.xml" --pdf --quiet 2>/dev/null; then
  PDF_OK=1
else
  echo "  xml2rfc --pdf failed; falling back to weasyprint on HTML"
  if command -v weasyprint >/dev/null 2>&1; then
    weasyprint "$DIR/$DRAFT.html" "$DIR/$DRAFT.pdf" >/dev/null 2>&1 \
      && PDF_OK=1 || PDF_OK=0
  else
    PDF_OK=0
  fi
fi
```

## Verification

`ietf-wimse-ect/draft-nennemann-wimse-ect-02.pdf` — 178 KB, generated via
`xml2rfc --pdf` (IETF-idiomatic layout with Noto fonts, title page,
bookmarks, and proper TOC). The fallback `weasyprint html->pdf` produces a
172 KB PDF that works but renders the html2rfc template instead of the
official IETF print layout; use it only if xml2rfc --pdf is unavailable.

## Reinstallation checklist (on a new machine)

1. `pipx install xml2rfc`
2. `pipx inject xml2rfc "weasyprint<60" pycairo pangocffi`
3. `/home/c/.local/share/pipx/venvs/xml2rfc/bin/python -m pip install "pydyf<0.10"`
4. Install system libs: `dnf install pango cairo harfbuzz` (Fedora) or
   `apt install libpango-1.0-0 libpangoft2-1.0-0 libharfbuzz0b` (Debian)
5. Test: `xml2rfc some-draft.xml --pdf`