Onepage PDF

onepage-pdf

Render HTML to one tall PDF page via headless Chrome, then crop the page to the real content height with PyMuPDF. Height is never predicted (print layout is not screen layout); it is measured after rendering, which is exact.

Requires: Python with pymupdf, plus a local Chrome or Edge.

Workflow

1. Inspect the source HTML first

Read the HTML and check four things; they decide whether --extra-css is needed:

1. Responsive breakpoints. Print media queries evaluate against the default paper width (~741px), NOT the @page size. Any @media (max-width: N) with N ≥ 741 will fire during print and collapse the desktop layout. For each such rule, write an override locking the desktop value with !important (e.g. .grid{grid-template-columns:repeat(3,1fr)!important}).
2. Glassmorphism. backdrop-filter blur is silently dropped in PDF output. If glass elements sit on busy backgrounds, add a print fallback: .glass{backdrop-filter:none!important;background:rgba(255,255,255,.88)!important}.
3. Scroll-reveal animations. Common class patterns (fade*, reveal*, animate*, aos) are forced visible automatically. Anything else that starts at opacity:0 needs an explicit opacity:1!important override.
4. vh/vw sizing. Viewport units resolve against the page area in print and drift ~1%; a min-height:100vh hero becomes ~187in tall on the bedrock page. Override such rules with fixed px values.

Put all overrides in one CSS file and pass it via --extra-css.

2. Convert

python scripts/onepage_pdf.py input.html -o output.pdf --width 1280 \
    [--extra-css fixes.css] [--replace subs.json --forbid words.txt]

• --width: match the design width of the page (snapped to 8px; non-8px page sizes hit MediaBox rounding bugs that spawn phantom pages).
• --replace: JSON [["old","new"], ...], applied in order — put longer / more specific strings first. Use for redaction before publishing.
• --forbid: one word per line; the script aborts if any survives in the HTML or in the final PDF text layer. Always pair with --replace.
• --crop pixel: switch to raster row-scanning if the vector crop misjudges (e.g. a decorative element painted taller than the real content).

The script self-handles: oversized-bedrock rendering with auto-retry on overflow, content cropping (MediaBox + CropBox rewritten identically for viewer compatibility), CJK-safe output paths, single-page assertion.

3. Verify

The script prints OK 1 page, WxHpt. Then:

1. Render a thumbnail and eyeball it (layout intact, no collapsed grids, backgrounds present, nothing cut at the bottom):

   import pymupdf
   doc = pymupdf.open("output.pdf")
   doc[0].get_pixmap(dpi=40).save("check.png")
   

2. If redaction was used, the forbid check already ran against the PDF text; still spot-check the rendered image for sensitive content in raster form.
3. Heed the script warnings: heights above 14400pt break Acrobat (Chrome, Firefox and WeChat preview are fine); "content nearly fills the bedrock" means inspect the tail for truncation.

Troubleshooting and mechanics

Read references/mechanics.md when output looks wrong (collapsed layout, missing backgrounds, blank page, phantom second page, blurry or missing CJK glyphs) — it documents the Chrome print-rendering rules this tool is built around, plus the CDP-based alternative route.