pdfrum-doc

Everything the catalog hangs off the page tree (ISO 32000-1 §12): outline bookmarks, destinations, links, annotations, the AcroForm data model, page labels, viewer preferences, the tagged structure tree, XMP metadata, and a PDF/A conformance report. It reads the object graph; it never rasterizes and never runs JavaScript.

use pdfrum_common::{Diagnostics, Limits};
use pdfrum_doc::page_label;
use pdfrum_object::{Array, Dict, Name, NoResolve, Object, PdfString};

// `/PageLabels` maps a *starting* page index to a rule; page 1 onwards is
// upper-case roman with the prefix `A-` (ISO 32000-1 §12.4.2).
let rule = Dict::from_pairs([
    (Name::from("S"), Object::Name(Name::from("R"))),
    (Name::from("P"), Object::Str(PdfString::literal(b"A-"))),
]);
let labels = Dict::from_pairs([(
    Name::from("Nums"),
    Object::Array(Array::of([Object::Int(1), Object::Dict(rule)])),
)]);
let catalog = Dict::from_pairs([(Name::from("PageLabels"), Object::Dict(labels))]);

let (limits, mut diags) = (Limits::default(), Diagnostics::default());
let label = page_label(&catalog, 2_u32, 3, &NoResolve, &limits, &mut diags);
assert_eq!(label.as_deref(), Some("A-II"));

Appearance generation returns an [AnnotOverlay]; it does not mutate the store. Readers take Option<&AnnotOverlay>, so the same annotation list can be read with generated appearances or without, and a caller that never asks for one pays nothing. [DocOptions] gates that generation, and both of its switches are off by default: the oracle builds every annotation list through the form-fill environment, which disables the /NeedAppearances widget path outright. Turn them on for the documented viewer behaviour instead.

A page label is a lower-bound lookup plus arithmetic, never a direct hit, and the two "no label" answers differ — a page index outside the document has no label at all, while a page inside it with no matching tree entry gets its one-based index as a decimal.

Part of pdfrum. #![forbid(unsafe_code)].

MIT OR Apache-2.0