Daniel VoshartandClaude Sonnet 5
f29436a1f6
Adds Metadata::regions: Vec<Region>, populated by parse_xmp from mwg-rs:Regions (MWG Region Guidelines v2.0) — the format Lightroom, digiKam and Picasa write for face/pet/focus/barcode regions. Read-only: LightCraft does not write regions yet (blocked on #92, which would otherwise clobber existing sidecars). - Canonicalises the mwg-rs/stArea/stDim namespaces so any prefix a writer picks resolves consistently, reusing the existing generic struct/array XMP machinery (handles both the element and attribute encodings transparently). - Area center-coordinates are converted to lightcraft_geom::Rect via Rect::from_center. Normalized units (the default, and the only unit we've seen in practice) need no AppliedToDimensions cross-reference; the rare pixel-unit region is converted when AppliedToDimensions is present, and dropped (not stored as a nonsense fraction) when it isn't. - Hostile/malformed regions (missing Area, NaN/absurd/zero/negative extents) are skipped individually rather than failing the whole list or panicking. - regions merges like keywords in fill_missing/overlay_user_fields, since it only ever comes from XMP today. Not included: nothing yet reads Metadata::regions (no catalog field, no UI, no command) — this is plumbing for a later PR, with no user-visible effect and no docs/parity.md row to update. cargo xtask ci passes (fmt, clippy -D warnings, test, parity, layers, assets, wasm). Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
lightcraft-meta (L1)
Photo metadata: EXIF, XMP (read + write), IPTC-IIM, and the containers that carry them.
API
| Function | Purpose |
|---|---|
read_exif(&[u8]) -> Metadata |
TIFF-structured Exif block (whole TIFF/DNG/raw file, or JPEG APP1 payload with/without Exif\0\0). try_read_exif reports header errors. |
from_tiff(&Tiff) -> Metadata |
Same, from an already parsed stream (used by lightcraft-raw). |
embedded(&[u8]) -> Embedded |
Sniffs JPEG / PNG / WebP / TIFF and returns the Exif, XMP (+ extended XMP), ICC and IPTC blocks. jpeg_segments, png_chunks, webp_chunks are the per-container walkers. |
parse_xmp(&str) -> Result<XmpData> |
Metadata + the opaque lc:settings JSON + every property (prefix:name, structs flattened as a:b/c:d). |
write_xmp(&Metadata, Option<&str>) -> String |
Complete <?xpacket?> packet; the second argument is LightCraft's full develop settings JSON. |
parse_iptc(&[u8]) -> Metadata |
IIM record 2: title (2:5), keywords (2:25), by-line (2:80), copyright (2:116), caption (2:120), date/time created (2:55/2:60). |
extract(&[u8]) -> Metadata |
Everything for a whole file. Precedence: EXIF → IPTC fills gaps → XMP overrides user fields (rating, label, title, caption, artist, copyright, keywords, GPS) and fills the rest. |
Metadata carries camera (make, model, serial, software), lens (make, model, serial, specification), capture
(date-time with UTC offset and milliseconds, exposure time, f-number, ISO incl. extended ISO, focal length and
35 mm equivalent, flash, exposure bias, program, metering, white balance), orientation, GPS, dimensions and the
user fields (artist, copyright, title, caption, keywords, hierarchical keywords, rating −1…5, colour label).
XMP namespaces
Written: dc, xmp, photoshop, exif, exifEX, tiff, lr (hierarchicalSubject) and ours,
lc = http://ns.lightcraft.app/lc/1.0/ (lc:settings, an opaque JSON string). Reading canonicalises
prefixes by namespace URI, handles attribute and element forms, rdf:Seq/Bag/Alt (x-default first),
rdf:parseType="Resource" and nested-description structs, predefined and numeric entities. Nesting depth
and node count are limited.
Robustness
No panics on malformed input: proptests feed random bytes to every container walker and random text to the XMP parser; truncation tests cut a sample JPEG at every byte.
Sources
CIPA DC-008 (Exif 2.32), TIFF 6.0, Adobe DNG 1.7 (tag numbers), ISO 16684-1 / Adobe XMP Specification
Parts 1–3 (packet, RDF serialisation, standard schemas, JPEG extended XMP), IPTC-IIM 4.2 and the IPTC Photo
Metadata Standard, ITU-T T.81 (JPEG markers), ICC.1 (APP2 embedding), PNG Specification 3rd ed. (eXIf,
iTXt), the WebP RIFF container specification, Adobe Photoshop File Format Specification (image resource
blocks). XML parsing: quick-xml (MIT). No third-party metadata code was consulted.