PDF export & import

const bytes = await store.exportPdf(); // the original PDF + your annotations
const markdown = store.toMarkdown({ title: 'Notes' });
const json = store.toJSON();

const bytes = await store.exportPdf(); // the original PDF + your annotations
const markdown = store.toMarkdown({ title: 'Notes' });
const json = store.toJSON();

Without components: exportPdf(pdfBytes, annotations, options), importAnnotations(pdfBytes, options), annotationsToMarkdown, annotationsToJSON / annotationsFromJSON from svelte-pdf-mini/core.

The contract

Standard annotations. Every kind is written as its PDF counterpart (Highlight, Underline, StrikeOut, Squiggly with QuadPoints; Square, Circle, Line, PolyLine, Polygon, Ink, Text, FreeText, Stamp) with an appearance stream, plus /Contents, /T (author), dates, /NM (id), popups and reply links. Apple Preview, Acrobat, Chrome and Firefox show them.
Lossless round trip. Fields PDF can’t express (palette key, label, tags, quote, Markdown, extra) are stored in a private /SPM_Data key on each annotation and in an embedded svelte-pdf-mini.json. Opening the file again with importFromPdf gives back exactly what you exported.
Edits elsewhere win. If someone recolours or moves an annotation in another app, the standard fields override the stored copy on import.
Foreign annotations already in the PDF are kept; with importFromPdf they load as origin: 'foreign' (policy: the foreign prop — 'editable', 'readonly' or 'hidden'). Deleting an editable one sticks: the store lists it in store.removedForeign, and store.exportPdf() passes that list as the remove option. Exporting yourself (in a worker, say)? Pass { remove: store.removedForeign }.

Options

Option	Default	Meaning
`mode`	`'incremental'`	Append an update and keep the original bytes, or `'full'` rewrite
`flatten`	`false`	Burn annotations into page content (no longer editable)
`prune`	`'ours'`	`'all'` also removes every foreign markup or shape annotation not in the list
`remove`	—	Ids of foreign annotations to delete (the ones the user deleted: `store.removedForeign`)
`producer`	—	Producer string written into the update

Apple Preview

Preview re-saves the whole file: it keeps /SPM_Data and appearance streams but drops /NM, /CA, /RC, /IRT and the embedded JSON. Import rebuilds from /SPM_Data and merges field by field, so a recolour made in Preview is picked up while labels and notes survive. Incremental updates match the original file's cross-reference format, which Preview requires.

Encrypted PDFs

Many publisher PDFs carry an owner password that only restricts permissions: they open without a password, and exportPdf decrypts them and writes a full, unencrypted copy (the restrictions go, like in pdf.js and Preview). A PDF that needs a password to open can’t be saved: that would strip its protection, so exportPdf throws a PdfSaveError (reason: 'password').

Check before the user starts annotating: store.saveSupport (set by importFromPdf), result.saveSupport from importAnnotations, or await saveSupport(bytes):

const support = await saveSupport(bytes); // { encrypted, canSave, saveBlockedReason? }
if (!support.canSave) warn('Annotations on this PDF can’t be saved');

const support = await saveSupport(bytes); // { encrypted, canSave, saveBlockedReason? }
if (!support.canSave) warn('Annotations on this PDF can’t be saved');

Bytes before the %PDF- header (some servers prepend them) are dropped on export.

Re-anchoring

Highlights store their quote with a little context. When a different version of the paper is opened, reanchor (prop or store.reanchor()) finds each quote again and moves its quads, flagging the ones it cannot find as extra.orphan.