Project: new layers take their item's label colour (#153)

build::default_label picked a new layer's label from its type alone
(comps Sandstone, images Lavender, ...), ignoring the label of the Project
item it was made from.

A layer made from an item (footage, comp, solid, 3D model) now copies the
item's label when it is created; every path that adds an item to a comp
(layer.addItem from the menus, Project panel, Timeline and viewer drops,
models, precomps, imports) builds its layer there. Layers keep their own
label when the item's changes later. Layers without an item keep the type
defaults.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/tests_project_items.rs

@@ -1,6 +1,6 @@
 //! Project panel item edits: move into folders, rename, label, comment, with undo.
 
-use effectcraft_project::ItemId;
+use effectcraft_project::{ItemId, LayerId};
 use serde_json::json;
 
 use crate::Session;
@@ -72,6 +72,34 @@ fn delete_and_duplicate_items() {
     assert!(s.project.item(dup).is_none());
 }
 
+/// A new layer takes its Project item's label (#153); layers made before keep their own when the
+/// item's label changes. Layers with no item keep their type's default.
+#[test]
+fn new_layers_take_their_items_label() {
+    use crate::color::Label;
+    use effectcraft_project::{Footage, FootageKind, ItemKind};
+    let mut s = Session::default();
+    let inner = s.execute("comp.new", json!({"name": "Inner", "width": 64, "height": 64, "duration": 1})).unwrap()["comp"].as_u64().unwrap();
+    s.execute("comp.new", json!({"name": "Main", "width": 64, "height": 64, "duration": 1})).unwrap();
+    s.execute("file.importPlaceholder", json!({"name": "Clip"})).unwrap();
+    let clip = s.state.project_selection[0].0;
+    let model = std::sync::Arc::make_mut(&mut s.project)
+        .add_item("Model", Label::Aqua, None, ItemKind::Footage(Footage { kind: FootageKind::Model, path: "missing.glb".into(), ..Default::default() }))
+        .0;
+    let solid = s.execute("layer.newSolid", json!({"name": "Solid", "color": "#406080"})).unwrap()["layer"].as_u64().unwrap();
+    let solid_item = s.active_comp().unwrap().layer(LayerId(solid)).unwrap().source.item().unwrap().0;
+    let label = |s: &Session, layer: &serde_json::Value| s.active_comp().unwrap().layer(LayerId(layer["layer"].as_u64().unwrap())).unwrap().label;
+    for (item, lab) in [(inner, "Blue"), (clip, "Green"), (model, "Orange"), (solid_item, "Fuchsia")] {
+        let before = s.execute("layer.addItem", json!({"item": item})).unwrap();
+        s.execute("project.setLabel", json!({"items": [item], "label": lab})).unwrap();
+        let after = s.execute("layer.addItem", json!({"item": item})).unwrap();
+        assert_eq!(label(&s, &after).name(), lab, "a new layer takes item {item}'s label");
+        assert_ne!(label(&s, &before).name(), lab, "a layer made before keeps its own");
+    }
+    let text = s.execute("layer.newText", json!({"text": "Hi"})).unwrap();
+    assert_eq!(label(&s, &text), Label::Red, "no item: the type's default");
+}
+
 #[test]
 fn property_group_edits() {
     let mut s = Session::default();

crates/project/src/build.rs

@@ -715,15 +715,15 @@ pub fn audio(ids: &mut Ids) -> PropGroup {
 
 // ---------------------------------------------------------------- layers
 
-/// Default label colour for a layer source (Labels preferences defaults).
+/// Label colour for a new layer: its Project item's label when it has one (later changes to the
+/// item's label leave existing layers alone), else the Labels preferences default for its type.
 pub fn default_label(src: &LayerSource, project: &Project) -> Label {
+    if let Some(it) = src.item().and_then(|i| project.item(i)) {
+        return it.label;
+    }
     match src {
         LayerSource::Comp { .. } => Label::Sandstone,
-        LayerSource::Footage { item } => match project.item(*item).map(|i| i.type_name()) {
-            Some("Image") | Some("Image Sequence") => Label::Lavender,
-            Some("Audio") => Label::SeaFoam,
-            _ => Label::Aqua,
-        },
+        LayerSource::Footage { .. } => Label::Aqua,
         LayerSource::Solid { .. } => Label::Red,
         LayerSource::Text => Label::Red,
         LayerSource::Shape => Label::Blue,