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Accessible PDFs and accessibility checks

Government documents have to be readable with a screen reader (Besluit digitale toegankelijkheid overheid, EN 301 549, WCAG 2.1 AA). For a PDF that means tags that give it structure, a document language and a title: PDF/UA (ISO 14289-1). Filinq can generate such PDFs, checks every PDF for the basics, warns before a document goes to publication, and points out problems in a template while you write it.

Generate an accessible PDF​

Ask for it per generation with pdfOptions.accessible:

POST /apps/filinq/api/documents/generate
{ "templateId": "…", "dataRefs": [], "options": { "pdfOptions": { "accessible": true, "title": "Besluit parkeervergunning", "lang": "nl-NL" } } }
  • The PDF is made by LibreOffice with tags and PDF/UA switched on, never by the standard PDF engine, which cannot write tags. With pdfa: true as well it keeps PDF/A-3.
  • The language comes from lang, else from the template's language, else from the Nextcloud default_language. With none of these, nothing is made and the answer says a language is missing.
  • The title comes from title, else from the template name.
  • Without LibreOffice on the server the request fails (503) and lists what was tried. You never get an untagged PDF in its place.
  • Filinq checks what LibreOffice returns. A PDF without tags, language or title is refused, not handed out as accessible.

How good the tags are depends on the template: real headings, alternative text on images and header cells in tables carry over into the PDF.

Files can be converted the same way: PdfConversionService::convertToPdf($file, ['accessible' => true]).

Accessibility checks​

Document validation checks every PDF for four things:

CheckFires when
pdf-not-taggedthe PDF has no structure tree, or is not marked as tagged
pdf-language-missingthe PDF does not name its language
pdf-title-missingthe PDF has no title in its metadata
pdfua-identifier-missinga tagged PDF does not say it follows PDF/UA

They show under Accessibility checks in the validation result, as warnings by default. An admin can make one blocking or switch it off in the validation.profiles app config, like any other check.

These checks look for the presence of these parts in the PDF. They do not certify PDF/UA: a PDF can pass them and still be hard to read. For a full check against the PDF/UA rules, use a dedicated validator.

Before publishing​

Publish on a document first runs the checks. If the document has open accessibility findings, you see them with the choice to publish anyway. If your organisation made one of those checks blocking, the document cannot be published until it is fixed.

While writing a template​

The template preview shows an Accessibility checklist:

  • images without alternative text, by number and file name
  • a heading that skips a level, such as a h3 straight after a h1
  • tables without header cells, by number and first cell
  • no language for the template or for this Nextcloud

It is advice: you can always save and preview.