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Author	SHA1	Message	Date
andodeki	e0d86274d8	feat(pdf): flatten annotations and form fields into page content ... Phase 5's `flatten_test.dart`. An annotation draws from its /AP /N stream, which lives beside the page rather than in it; flattening moves that appearance into the page's own content and removes the annotation, so what is drawn is part of the page and cannot be turned off, edited or extracted as a field. That is what "finalise this form" and "make these comments permanent" mean, and it is irreversible by design. The placement transform is the whole problem, and it is §12.5.5: transform the /BBox by /Matrix, take the bounding box of the *result*, then fit that onto /Rect. Skip a step and the stamp lands at the origin, or in the right place at the wrong size, and the page still renders. A rotated appearance is the case that exposes it — rotation swaps the transformed box's width and height, so fitting the untransformed box squashes it. What is refused matters as much as what is done: - **No appearance stream**: left in place and reported. Dropping it loses it; inventing an appearance draws something the producer never specified. - **Hidden or /NoView**: not drawn on screen, so burning it in would *add* ink the user never saw. - **A /Popup**: the pop-up window of another annotation, never drawn on the page itself. Appearances are painted as XObjects rather than having their operators spliced in. Splicing needs the stream's resources merged into the page's with every name collision renamed, and it loses the /BBox clip an XObject applies for free. `pdf-document` cannot depend on `pdf-graphics` — the crate boundary is cos -> document -> graphics and inverting it to reuse `write_ops` would be a far worse trade than emitting the four operators (`q`, `cm`, `Do`, `Q`) directly. The number formatting follows the same shortest-exact rule as `content_edit::write_real`, and for the same reason. Verified by mutation, five defects, each confirmed red: placement matrix ignored 1 fail /BBox not transformed first 2 fail hidden check removed 1 fail annotation kept after flattening 7 fail existing page content dropped 1 fail **Externally verified, and it found a real gap.** Flattening the sample's seven annotations passed `qpdf --check` and kept every text run — but poppler still reported `Form: AcroForm` on a document with no fields left, because the catalogue entry survived. A viewer may still offer to fill in a form that no longer exists. `remove_acroform_if_empty` drops it, but only when *no* widget survives anywhere: flattening one page of a three-page form must not strip the fields still live on the others. before: Form: AcroForm after: Form: none `flatten_document` is the whole-document entry point — every page, then the form entry — and re-parses between pages because each flatten appends a revision the next must read. 22 round-trip tests through the saved file, including that flattening twice is idempotent (a Do count that grows on every save is how a "flatten" button pressed twice doubles every stamp), that existing page resources survive, and that a /AP /N state dictionary resolves through /AS. Engine suite 1075 -> 1108. Remaining in Phase 5: object compaction, redaction, and outline, page label and struct-tree editing.	2026-08-17 12:03:59 +00:00