awaforge

pdfCatalog

AGPL-3.0-onlyRelease 2L4

Typing of the /Type /Catalog dictionary, ISO 32000-2 §7.7.2 — root of the document tree.

Module pdfCatalog | Source packages/front/office/pdf/src/document/catalog.js | Deps pdfErrors, pdfParser | Worker-safe yes

Extracts the canonical entries of the root dictionary referenced by trailer.root. Unrecognised entries are preserved in _extras — useful for extensions and non-destructive round trips. /Type is validated strictly (when present it must be /Catalog) so that a bad xref offset cannot silently type an arbitrary dictionary as the catalog.

Resolve

const cat = runtime.resolve('pdfCatalog');
// Returns: { typeCatalog }

API

Method Signature Returns
typeCatalog (dict: PdfDict) => TypedCatalog Typed record.

TypedCatalog shape

{
    pages:    { num, gen },         // /Pages — required
    version?: string,               // /Version (overrides the header)
    pageLayout?: string,            // /PageLayout
    pageMode?:   string,            // /PageMode
    lang?:       string,            // /Lang
    outlines?:   PdfRef,            // /Outlines
    metadata?:   PdfRef,            // /Metadata (XMP stream)
    structTreeRoot?: PdfRef,        // /StructTreeRoot (tagged PDF)
    acroForm?:   PdfObject,         // /AcroForm
    names?:      PdfObject,         // /Names
    dests?:      PdfObject,         // /Dests
    viewerPrefs?: PdfObject,        // /ViewerPreferences
    pageLabels?:  PdfObject,        // /PageLabels
    markInfo?:    PdfObject,        // /MarkInfo
    ocProperties?: PdfObject,       // /OCProperties
    outputIntents?: PdfObject,      // /OutputIntents
    raw:      PdfDict,
    _extras:  Object<string, PdfObject>
}

Examples

Reaching the Catalog

const doc = api.read(bytes);
doc.catalog.pages;          // { num, gen } — page-tree root
doc.catalog.metadata;       // reference to the XMP stream, when present

Following the Outlines reference

if (doc.catalog.outlines) {
    const root = doc._raw.resolve(doc.catalog.outlines);
    const items = runtime.resolve('pdfOutline').walkOutline(root, doc._raw.resolve);
}

Inspecting _extras

Object.keys(doc.catalog._extras);
// e.g. ['MyProprietaryKey'] when the PDF carries an entry outside §7.7.2

Errors

Code Class When
pdf/catalog/not-dict ParseError Argument is not a dictionary.
pdf/catalog/bad-type ParseError /Type present but not /Catalog.
pdf/catalog/missing-pages ParseError /Pages missing or not a reference.

See also