glu
htmlbag module

The glu.htmlbag module

The glu.htmlbag module hands an in-memory HTML payload directly to glu’s HTML rendering pipeline, skipping the disk roundtrip of writing the HTML to a file just so glu file.html can read it back.

The intended user is a Lua script that builds HTML on the fly — for example, an XSL-FO walker (see boxesandglue-examples/glu/xslfo/foproc.lua) — and wants to produce a PDF in a single glu invocation.

local htmlbag = require("glu.htmlbag")

Functions

Function Description
render(html_string, output_pdf [, opts]) Render an HTML string to a PDF

render

Render an HTML payload to a PDF file.

htmlbag.render("<html><body><p>Hello.</p></body></html>", "out.pdf")

Parameters:

  • html_string — the full HTML document as a string. The same content model as glu’s HTML mode applies: <style> tags, <link> external stylesheets, @page rules, inline styles. See HTML mode and htmlbag for the supported HTML/CSS subset.
  • output_pdf — path to the PDF file to write.
  • opts (optional) — either a string (treated as base_dir) or an options table:
    Key Type Description
    base_dir string Directory to resolve relative CSS paths against (default .).
    format string PDF conformance level: PDF (default), PDF/A-3b, PDF/X-3, PDF/X-4, PDF/UA / PDF/UA-1 (ISO 14289-1), PDF/UA-2 (ISO 14289-2 on PDF 2.0).
    lang string BCP 47 language tag written to PDF /Lang and used as the default hyphenation language. Required for any PDF/UA* format.
    title string PDF /Title and XMP dc:title. Required for any PDF/UA* format (readers show it instead of the filename).

The function uses the same pipeline as glu file.html — installed callbacks, the auxiliary file mechanism for cross-references, and PDF/UA tagging if format is set to one of the UA values. It returns nothing on success; it raises a Lua error on failure.

Example: a tiny FO-like walker 

local htmlbag = require("glu.htmlbag")

local html = [[
<!DOCTYPE html>
<html>
<head>
  <style>
    @page { size: A5; margin: 2cm; }
    body { font-family: serif; font-size: 11pt; }
  </style>
</head>
<body>
  <h1>Generated from Lua</h1>
  <p>No intermediate HTML file on disk.</p>
</body>
</html>
]]

htmlbag.render(html, "generated.pdf")

Run with:

glu walker.lua    # writes generated.pdf
Lua script modejson module