Alt+B / Alt+Shift+B toggle layer sampling

layer.sampling takes `toggle`: layers that all have the sampling already get the
other one. The Bilinear and Bicubic menu entries, which carry the keys, pass it.

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

crates/engine/src/commands/layer_menu.rs

@@ -76,6 +76,13 @@ fn sampling(s: &mut Session, p: &Value) -> Result<Value> {
         "bicubic" => Sampling::Bicubic,
         q => return Err(bad("layer.sampling", format!("sampling must be bilinear|bicubic, not `{q}`"))),
     };
+    // `toggle`: layers that all have it already get the other one.
+    let all = s.project.comp(cid).is_some_and(|c| c.layers.iter().filter(|l| ids.contains(&l.id)).all(|l| l.switches.sampling == q));
+    let q = match q {
+        Sampling::Bilinear if all && b_p(p, "toggle").unwrap_or(false) => Sampling::Bicubic,
+        Sampling::Bicubic if all && b_p(p, "toggle").unwrap_or(false) => Sampling::Bilinear,
+        q => q,
+    };
     s.edit("Layer Sampling", None, |proj, _| {
         for l in proj.comp_mut(cid).ok_or(EngineError::NoComp)?.layers.iter_mut().filter(|l| ids.contains(&l.id)) {
             l.switches.sampling = q;
@@ -800,7 +807,7 @@ fn sequence(s: &mut Session, p: &Value) -> Result<Value> {
 pub fn specs() -> Vec<CommandSpec> {
     vec![
         cmd!("layer.quality", "Quality", [], None, "{layers?, quality: best|draft|wireframe}", has_layers, quality),
-        cmd!("layer.sampling", "Sampling", [], None, "{layers?, sampling: bilinear|bicubic}", has_layers, sampling),
+        cmd!("layer.sampling", "Sampling", [], None, "{layers?, sampling: bilinear|bicubic, toggle?}", has_layers, sampling),
         cmd!("layer.frameBlending", "Frame Blending", [], None, "{layers?, mode: off|frameMix|pixelMotion}", has_layers, frame_blending),
         cmd!("layer.hideOtherVideo", "Hide Other Video", ["Layer", "Switches"], Some("Cmd+Alt+Shift+V"), "{layers?}", has_layers, hide_other_video),
         cmd!("layer.showAllVideo", "Show All Video", ["Layer", "Switches"], None, "{comp?}", has_comp, show_all_video),

crates/engine/src/menus.rs

@@ -785,8 +785,8 @@ Layer
     Draft | layer.quality {"quality":"draft"} | Cmd+Shift+U
     Wireframe | layer.quality {"quality":"wireframe"} | Cmd+Alt+Shift+U
     ---
-    Bilinear | layer.sampling {"sampling":"bilinear"} | Alt+B
-    Bicubic | layer.sampling {"sampling":"bicubic"} | Alt+Shift+B
+    Bilinear | layer.sampling {"sampling":"bilinear","toggle":true} | Alt+B
+    Bicubic | layer.sampling {"sampling":"bicubic","toggle":true} | Alt+Shift+B
   Switches
     Hide Other Video | layer.hideOtherVideo
     Show All Video | layer.showAllVideo

crates/engine/src/tests_menu_cmds.rs

@@ -52,6 +52,30 @@ fn layer_quality_sampling_frame_blending_and_undo() {
     assert!(s.execute("layer.quality", json!({"quality": "fancy"})).is_err());
 }
 
+/// `layer.sampling {toggle}` (Alt+B, Alt+Shift+B): layers that all have the sampling already get
+/// the other one; without `toggle` it is only set.
+#[test]
+fn layer_sampling_toggles_when_every_layer_has_it() {
+    let mut s = comp();
+    let a = solid(&mut s, "#ff0000");
+    let b = solid(&mut s, "#00ff00");
+    let sampling = |s: &Session| [layer(s, a).switches.sampling, layer(s, b).switches.sampling];
+    let bicubic = json!({"layers": [a, b], "sampling": "bicubic", "toggle": true});
+    s.execute("layer.sampling", bicubic.clone()).unwrap();
+    assert_eq!(sampling(&s), [Sampling::Bicubic; 2]);
+    s.execute("layer.sampling", bicubic.clone()).unwrap();
+    assert_eq!(sampling(&s), [Sampling::Bilinear; 2]);
+    s.execute("layer.sampling", json!({"layers": [a, b], "sampling": "bilinear", "toggle": true})).unwrap();
+    assert_eq!(sampling(&s), [Sampling::Bicubic; 2]);
+    // Mixed layers all get the one asked for.
+    s.execute("layer.sampling", json!({"layers": [a], "sampling": "bilinear"})).unwrap();
+    s.execute("layer.sampling", bicubic).unwrap();
+    assert_eq!(sampling(&s), [Sampling::Bicubic; 2]);
+    // Without `toggle` it stays.
+    s.execute("layer.sampling", json!({"layers": [a, b], "sampling": "bicubic"})).unwrap();
+    assert_eq!(sampling(&s), [Sampling::Bicubic; 2]);
+}
+
 /// `layer.setSwitch {others: true}` (Alt-click on an A/V feature): the layer stands alone, the
 /// other layers come back the next time.
 #[test]

crates/engine/src/tests_settings.rs

@@ -418,8 +418,8 @@ fn default_keys_for_commands_that_had_none() {
     for (id, params, key) in [
         ("edit.pasteReversedKeyframes", json!(null), "Cmd+Shift+V"),
         ("edit.purge", json!({"what": "snapshot"}), "Cmd+Shift+F5"),
-        ("layer.sampling", json!({"sampling": "bilinear"}), "Alt+B"),
-        ("layer.sampling", json!({"sampling": "bicubic"}), "Alt+Shift+B"),
+        ("layer.sampling", json!({"sampling": "bilinear", "toggle": true}), "Alt+B"),
+        ("layer.sampling", json!({"sampling": "bicubic", "toggle": true}), "Alt+Shift+B"),
         ("view.res.custom", json!(null), "Cmd+Alt+J"),
         ("file.setProxy", json!(null), "Cmd+Alt+P"),
         ("file.openRecent", json!(null), "Cmd+Alt+Shift+P"),