Catalog/UI: show XMP face/pet regions in the loupe view

Threads the Vec<Region> that lightcraft-meta already reads from XMP
(MWG-RS) through to the screen, so it's no longer inert:

- catalog::Meta gains a `regions` field (catalog now depends on
  lightcraft-meta, which doesn't depend back on catalog, so no cycle).
- crates/engine/src/files.rs (meta_of) and src/sidecar.rs (parse_sidecar
  / merge_into) populate it for both embedded-XMP and external-sidecar
  photos, mirroring how `keywords` is already handled.
- ui-egui's loupe view (panels/detail.rs) draws each region as a
  rectangle over the photo via the existing CanvasMap, color-coded by
  kind (Face/Pet/other) with its name label if present, right alongside
  the existing info overlay. Read-only, no new interaction.

New end-to-end test (regions_from_sidecar_are_read_on_import) covers a
region written to a sidecar reaching Photo.meta.regions through real
import, not just the parser. cargo xtask ci green (fmt, clippy -D warnings, test, parity, layers, assets, wasm).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Cargo.lock

@@ -2095,6 +2095,7 @@ version = "0.2.1"
 dependencies = [
  "crc32fast",
  "lightcraft-develop",
+ "lightcraft-meta",
  "log",
  "proptest",
  "serde",
@@ -2348,6 +2349,7 @@ dependencies = [
  "lightcraft-develop",
  "lightcraft-engine",
  "lightcraft-geom",
+ "lightcraft-meta",
  "lightcraft-pipeline",
  "lightcraft-preview",
  "lightcraft-raster",

crates/catalog/Cargo.toml

@@ -10,6 +10,7 @@ workspace = true
 
 [dependencies]
 lightcraft-develop = { workspace = true }
+lightcraft-meta = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
 thiserror = { workspace = true }

crates/catalog/src/model.rs

@@ -183,6 +183,9 @@ pub struct Meta {
     pub copyright_url: String,
     pub creator: String,
     pub keywords: Vec<String>,
+    /// Face/pet/focus regions read from XMP (MWG-RS). Read-only today; nothing in
+    /// LightCraft writes regions yet.
+    pub regions: Vec<lightcraft_meta::Region>,
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]

crates/engine/src/files.rs

@@ -38,6 +38,7 @@ fn meta_of(m: &lightcraft_meta::Metadata) -> (Meta, Option<String>) {
         copyright_url: m.copyright_url.clone().unwrap_or_default(),
         creator: m.artist.clone().unwrap_or_default(),
         keywords: m.keywords.clone(),
+        regions: m.regions.clone(),
     };
     (meta, m.capture_time.as_ref().map(|d| d.to_iso()))
 }

crates/engine/src/sidecar.rs

@@ -99,6 +99,7 @@ pub struct SidecarData {
     pub alt_text: Option<String>,
     pub extended_description: Option<String>,
     pub keywords: Option<Vec<String>>,
+    pub regions: Option<Vec<lightcraft_meta::Region>>,
     /// Capture time (ISO 8601) from `exif:DateTimeOriginal`, `photoshop:DateCreated` or
     /// `xmp:CreateDate` (first found). Used only when the file itself has no capture time.
     pub captured: Option<String>,
@@ -133,6 +134,7 @@ pub fn parse_sidecar(xmp: &str, raw: bool) -> std::result::Result<SidecarData, S
         alt_text: m.alt_text.clone(),
         extended_description: m.extended_description.clone(),
         keywords: (!m.keywords.is_empty()).then(|| m.keywords.clone()),
+        regions: (!m.regions.is_empty()).then(|| m.regions.clone()),
         captured: m.capture_time.map(|d| d.to_iso()),
         ..Default::default()
     };
@@ -202,6 +204,9 @@ pub fn merge_into(p: &mut Photo, sc: &SidecarData, now: &str) -> bool {
     if let Some(k) = &sc.keywords {
         m.keywords = k.clone();
     }
+    if let Some(r) = &sc.regions {
+        m.regions = r.clone();
+    }
     let develop = match &sc.develop {
         Some(DevelopPatch::Full(s)) => (**s).clone(),
         Some(DevelopPatch::Partial(v)) => {

crates/engine/src/tests_xmp.rs

@@ -173,6 +173,51 @@ fn foreign_crs_sidecar_on_import_and_read_from_file() {
     let _ = std::fs::remove_dir_all(&src);
 }
 
+const MWG_REGIONS: &str = r#"<?xpacket begin="" id="W5M0MpCehiHzreSzNTczkc9d"?>
+<x:xmpmeta xmlns:x="adobe:ns:meta/">
+ <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
+  <rdf:Description rdf:about=""
+    xmlns:mwg-rs="http://www.metadataworkinggroup.com/schemas/regions/"
+    xmlns:stArea="http://ns.adobe.com/xmp/sType/Area#"
+    xmlns:stDim="http://ns.adobe.com/xap/1.0/sType/Dimensions#">
+   <mwg-rs:Regions>
+    <rdf:Description>
+     <mwg-rs:AppliedToDimensions stDim:w="100" stDim:h="100" stDim:unit="pixel"/>
+     <mwg-rs:RegionList>
+      <rdf:Bag>
+       <rdf:li>
+        <rdf:Description mwg-rs:Name="Jane Doe" mwg-rs:Type="Face">
+         <mwg-rs:Area stArea:x="0.5" stArea:y="0.5" stArea:w="0.3" stArea:h="0.4" stArea:unit="normalized"/>
+        </rdf:Description>
+       </rdf:li>
+      </rdf:Bag>
+     </mwg-rs:RegionList>
+    </rdf:Description>
+   </mwg-rs:Regions>
+  </rdf:Description>
+ </rdf:RDF>
+</x:xmpmeta>
+<?xpacket end="w"?>"#;
+
+/// A face region written by Lightroom (MWG-RS) into a sidecar reaches `Photo.meta.regions` on
+/// import — the same path real catalogs use, exercised end to end rather than just at the parser.
+#[test]
+fn regions_from_sidecar_are_read_on_import() {
+    let src = temp_dir("regions");
+    write_png(&src.join("portrait.png"), 9);
+    std::fs::write(src.join("portrait.xmp"), MWG_REGIONS).unwrap();
+    let mut s = Session::new().with_fs();
+    let r = s.execute("library.import", &json!({"paths": [src.to_string_lossy()]})).unwrap();
+    assert_eq!(r["sidecars"], 1);
+    let p = s.catalog.photos().next().unwrap().clone();
+    assert_eq!(p.meta.regions.len(), 1);
+    let region = &p.meta.regions[0];
+    assert_eq!(region.name.as_deref(), Some("Jane Doe"));
+    assert_eq!(region.kind, lightcraft_meta::RegionKind::Face);
+    assert!((region.rect.width() - 0.3).abs() < 1e-9, "{:?}", region.rect);
+    let _ = std::fs::remove_dir_all(&src);
+}
+
 fn synthetic_dng(xmp: &str) -> Vec<u8> {
     synthetic_dng_with(Some(xmp), lightcraft_meta::Metadata::default())
 }

crates/ui-egui/Cargo.toml

@@ -10,6 +10,7 @@ workspace = true
 
 [dependencies]
 lightcraft-geom = { workspace = true }
+lightcraft-meta = { workspace = true }
 lightcraft-color = { workspace = true }
 lightcraft-raster = { workspace = true }
 lightcraft-develop = { workspace = true }

crates/ui-egui/src/panels/detail.rs

@@ -333,6 +333,7 @@ pub fn show(app: &mut LightcraftApp, ui: &mut egui::Ui) {
     let map = CanvasMap::new(&frame, img_rect);
     let resp = ui.interact(canvas, egui::Id::new("loupe"), Sense::click_and_drag());
     info_overlay(app, &p, canvas, &photo);
+    region_overlay(&p, &map, &photo);
     // a fine grid while a transform (geometry) slider is dragged, to judge verticals
     if app.ui.dragging_control.as_deref().is_some_and(|c| c.starts_with("geometry.")) {
         let n = 12;
@@ -420,6 +421,28 @@ fn info_overlay(app: &LightcraftApp, p: &egui::Painter, canvas: Rect, photo: &li
     register(p.ctx(), "canvas:infoOverlay", Rect::from_min_max(canvas.min, pos2(canvas.left() + 320.0, y)));
 }
 
+/// Face/pet/focus regions read from XMP (MWG-RS), drawn as boxes over the photo. Read-only —
+/// LightCraft doesn't write regions yet.
+fn region_overlay(p: &egui::Painter, map: &CanvasMap, photo: &lightcraft_catalog::Photo) {
+    use lightcraft_meta::RegionKind;
+    let t = Tokens::get(p.ctx());
+    for r in &photo.meta.regions {
+        let color = match r.kind {
+            RegionKind::Face => Color32::from_rgb(255, 214, 10),
+            RegionKind::Pet => Color32::from_rgb(120, 220, 120),
+            RegionKind::Focus | RegionKind::BarCode | RegionKind::Other(_) => Color32::from_white_alpha(140),
+        };
+        let rect = Rect::from_two_pos(map.screen(Point::new(r.rect.x0, r.rect.y0)), map.screen(Point::new(r.rect.x1, r.rect.y1)));
+        p.rect_stroke(rect, 2.0, Stroke::new(1.5, color), StrokeKind::Outside);
+        if let Some(name) = &r.name {
+            let g = p.layout_no_wrap(name.clone(), t.font(12.0), color);
+            let at = pos2(rect.left(), rect.top() - g.size().y - 2.0);
+            p.galley(at + vec2(1.0, 1.0), g.clone(), Color32::from_black_alpha(200));
+            p.galley(at, g, color);
+        }
+    }
+}
+
 /// A raw shown from its embedded JPEG (issue #10): a pill at the canvas' top centre saying so;
 /// hovering it explains (registered as `notice:previewOnly:loupe`).
 fn preview_only_pill(ui: &mut egui::Ui, canvas: Rect, reason: &str) {