PDF/A, ZUGFeRD and PDF/UA

All three are opt-in Cargo features. Calling the method without its feature does not silently produce a non-conformant file – render() returns RenderError::PdfAFeatureDisabled, ZugferdFeatureDisabled or TaggedPdfFeatureDisabled.

PDF/A-3b

Feature pdf-a, method Document::pdf_a3b():

let mut doc = Document::new(PageFormat::A4).margin(Margin::all(40.0)).pdf_a3b();
doc.metadata.title = Some("PDF/A-3b Demo".to_string());

• XMP metadata kept in sync with /Info.
• An /OutputIntent with an embedded sRGB ICC profile – the ICC’s own 3 KiB sRGB2014.icc reference profile, so the feature costs about 4.3 KiB gzip in the WASM build.
• A transparency-group colour space on any page with an alpha-channel image.

Verified with the veraPDF validator, locally and in CI (the pdf-a-conformance job renders examples/demo_pdf_a3b.rs).

ZUGFeRD / Factur-X

Feature zugferd (implies pdf-a), method Document::zugferd_xml(bytes):

let doc = Document::new(PageFormat::A4).zugferd_xml(INVOICE_XML);

It embeds a caller-supplied EN 16931 invoice XML as an associated file (/AF, /Names/EmbeddedFiles) with the Factur-X XMP extension schema. This crate embeds only – it never generates or validates the XML. examples/demo_zugferd.rs embeds a sample from the ZUGFeRD reference corpus; the result was checked with veraPDF (PDF/A-3b container) and the Mustang validator (the PDF and the embedded XML against EN 16931). The showcase has the PDF.

Tagged PDF / PDF/UA-1

Feature tagged-pdf (implies pdf-a), method Document::pdf_ua():

let mut doc = Document::new(PageFormat::A4)
    .pdf_ua()
    .lang("en-US")
    .watermark(Watermark::new("SAMPLE"));
doc.add(Image::new(LOGO)?.width(100.0).alt("lightweight-pdf logo"));

• A real structure tree (/StructTreeRoot) with one structure element per heading, paragraph, table row and cell, list item and figure.
• Marked content (BDC/EMC with MCIDs) in every content stream, and /Lang.
• Watermark, header and footer are marked as artifacts – excluded from the reading order.
• Image::alt(text) sets /Alt. Without it, an empty /Alt keeps the structure tree well-formed, but render_with_diagnostics() warns and the file is not PDF/UA-1-conformant until you supply real alt text. The crate does not invent placeholder text.

pdf_ua() implies pdf_a3b(), so the output is both. Verified with veraPDF’s ua1 and 3b profiles, locally and in CI (pdf-a-conformance job, examples/demo_pdf_ua.rs). The showcase has the PDF.