untagged-content

All codes

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

What happened

Under PDF/UA-1, something was drawn outside every structure element and artifact: a path, an image or text that is neither part of the document’s structure nor marked as decoration.

Why

Assistive technology reads a tagged document through its structure tree, and skips content outside it or reads it out of order. For this reason, the PDF/UA-1 standard for accessible PDF (ISO 14289-1 §7.1) requires every piece of content to be tagged or marked as an artifact. This is condition 01-005 of the Matterhorn Protocol, the PDF Association’s checklist of PDF/UA failures.

How to fix

Draw real content inside Surface::tag (or give a text run TextRun::tag) and decoration, such as rules, backgrounds and page numbers, inside Surface::artifact. Builder::tagging_diagnostics lists what is still untagged on each page.

Example

surface.path(|p| { p.rect(rule); }).fill(FillRule::NonZero);
builder.finish()?; // untagged-content: wrap it in surface.artifact(ArtifactKind::Layout, …)

Data fields

• page: the page’s index (0-based).
• content: what was drawn: path, image or text.
• count: how many drawings of that kind.