missing-lang

All codes

• Type: error
• Kind: usage (the caller misused the API)

What happened

A PDF/UA-1 document (Profile::PdfUa1) reached Builder::finish without a natural language: Builder::lang was never called, or was given a blank tag.

Why

A screen reader picks its voice and pronunciation from the document’s language (/Lang in the catalog, ISO 32000-2 §14.9.2). The PDF/UA-1 standard for accessible PDF (ISO 14289-1 §7.2) requires that the language of all text can be determined. These are conditions 11-001 and 11-006 of the Matterhorn Protocol, the PDF Association’s checklist of PDF/UA failures.

How to fix

Set the document’s language with a BCP 47 tag, the standard language code of the web, such as en-GB or fr. Text in another language can carry its own tag with Tag::with_lang.

Example

builder.lang("en-GB");

Data fields

None.