Address review: regression tests and overlay outline parity

- Add two regression tests in tests_masking.rs (next to mask_overlay_keys_and_pins)
  covering #2210: every visible mask is outlined under the all-masks overlay while
  only the selected mask registers maskHandle: widgets, and an unselected mask's
  outline is painted on screen.
- Match the outline condition to the painted region: only outline masks with
  components, like view_overlay already does.
- Add examples/mask_overlay_shot.rs (+ dev-dep png) to render a screenshot of the
  overlay for the PR.
- Revert the earlier standalone test in headless.rs; make mask_overlay and
  CanvasMap::new pub(crate) so the masking tests can reach them.

Cargo.lock

@@ -3525,6 +3525,7 @@ dependencies = [
  "lightcraft-slideshow",
  "lightcraft-testkit",
  "log",
+ "png",
  "serde",
  "serde_json",
  "toml",

crates/ui-egui/Cargo.toml

@@ -35,6 +35,7 @@ lightcraft-denoise = { workspace = true, features = ["runtime"] }
 lightcraft-codecs = { workspace = true }
 lightcraft-faces = { workspace = true }
 lightcraft-merge = { workspace = true }
+png = { workspace = true }
 
 [build-dependencies]
 serde_json = { workspace = true }

crates/ui-egui/examples/mask_overlay_shot.rs

@@ -0,0 +1,49 @@
+//! Render a screenshot of the masking view with the all-masks overlay on: several visible masks,
+//! each outlined, only the selected one draggable. Used to attach a visual to PR #2210.
+//!
+//! Run: `cargo run -p lightcraft-ui-egui --example mask_overlay_shot -- <out.png>`
+
+use std::time::Duration;
+
+use lightcraft_raster::Rgba8;
+use serde_json::json;
+
+use lightcraft_ui_egui::headless::Headless;
+use lightcraft_ui_egui::{LightcraftApp, Services};
+
+fn main() {
+    let out = std::env::args().nth(1).unwrap_or_else(|| "mask-overlay.png".into());
+    let t = Duration::from_secs(20);
+
+    let services = Services { png: None, ..Default::default() };
+    let app = LightcraftApp::new(lightcraft_engine::Session::with_demo(), services);
+    let mut h = Headless::new(app, [1200.0, 800.0], 1.0);
+    let _ = h.request("ui.set", json!({"view": "detail"}), t);
+    let _ = h.request("engine.execute", json!({"command": "panel.masking"}), t);
+
+    // A few visible masks; mask.add selects the newest, so the last one is selected.
+    for params in [
+        json!({"kind": "radial", "center": [0.3, 0.4], "rx": 0.12, "ry": 0.12}),
+        json!({"kind": "linear", "start": [0.65, 0.25], "end": [0.65, 0.6]}),
+        json!({"kind": "radial", "center": [0.7, 0.65], "rx": 0.1, "ry": 0.14, "angle": 30}),
+    ] {
+        let _ = h.request("engine.execute", json!({"command": "mask.add", "params": params}), t);
+    }
+    let _ = h.request("engine.execute", json!({"command": "view.maskOverlayAll"}), t);
+    let _ = h.request("engine.execute", json!({"command": "view.maskPins", "params": {"show": false}}), t);
+    h.settle(Duration::from_secs(120));
+
+    let px = h.view.paint(&Default::default());
+    let rgba = Rgba8::from_fn(px.width(), px.height(), |x, y| {
+        let p = px.pixels[y * px.width() + x];
+        [p.r(), p.g(), p.b(), p.a()]
+    });
+
+    let file = std::fs::File::create(&out).expect("create png");
+    let mut enc = png::Encoder::new(file, rgba.width as u32, rgba.height as u32);
+    enc.set_color(png::ColorType::Rgba);
+    enc.set_depth(png::BitDepth::Eight);
+    let mut w = enc.write_header().expect("png header");
+    w.write_image_data(&rgba.as_bytes()).expect("encode png");
+    println!("wrote {out} ({}, {})", rgba.width, rgba.height);
+}

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

@@ -81,7 +81,7 @@ pub struct CanvasMap {
 }
 
 impl CanvasMap {
-    fn new(frame: &Frame, rect: Rect) -> CanvasMap {
+    pub(crate) fn new(frame: &Frame, rect: Rect) -> CanvasMap {
         let k = 8.0f32;
         let (w, h) = ((rect.width() * k).round().max(1.0) as usize, (rect.height() * k).round().max(1.0) as usize);
         let to_norm = frame.out_to_norm(w, h);
@@ -1996,7 +1996,7 @@ fn color_range_pick(app: &mut LightcraftApp, ui: &egui::Ui, resp: &egui::Respons
 /// The Masking tool on the photo: outlines and handles of the selected mask, a pin per mask
 /// component (click selects its mask, drag moves the component), and brush painting. The mask
 /// itself shows as a rendered overlay ([`view_overlay`]).
-fn mask_overlay(app: &mut LightcraftApp, ui: &mut egui::Ui, resp: &egui::Response, map: &CanvasMap, d: &DevelopSettings) {
+pub(crate) fn mask_overlay(app: &mut LightcraftApp, ui: &mut egui::Ui, resp: &egui::Response, map: &CanvasMap, d: &DevelopSettings) {
     let long = (map.rect.width().max(map.rect.height())) as f64;
     let active = app.session.active_mask;
     let clip = app.canvas_rect.unwrap_or(map.rect);
@@ -2013,8 +2013,9 @@ fn mask_overlay(app: &mut LightcraftApp, ui: &mut egui::Ui, resp: &egui::Respons
         let sel = Some(m.id) == active;
         // Ctrl+Shift+O (`mask_overlay_all`) shows every visible mask's region; outline each one
         // too, not just the selected mask. Handles and the rotation grip stay on the selected
-        // mask so nothing else becomes draggable.
-        let show_outline = sel || (app.ui.mask_overlay_all && m.visible);
+        // mask so nothing else becomes draggable. The component check keeps this in step with the
+        // painted region (`view_overlay` at detail.rs:1354 only covers masks with components).
+        let show_outline = sel || (app.ui.mask_overlay_all && m.visible && !m.components.is_empty());
         let stroke_a: u8 = if sel { 230 } else { 170 };
         for (ci, c) in m.components.iter().enumerate() {
             match &c.shape {

crates/ui-egui/src/tests_masking.rs

@@ -317,6 +317,63 @@ fn mask_overlay_keys_and_pins() {
     h.settle(SETTLE);
 }
 
+/// #2210: Ctrl+Shift+O (the all-masks overlay) draws the white outline of every visible
+/// Radial/Linear mask, not just the selected one — but only the selected mask registers
+/// `maskHandle:` elements, so nothing else becomes draggable.
+#[test]
+fn all_masks_overlay_outlines_every_visible_mask_but_only_the_selected_one_is_draggable() {
+    let mut h = detail("panel.masking");
+    // Two visible radial masks; mask 2 ends up selected (mask.add selects the new one).
+    exec(&mut h, "mask.add", json!({"kind": "radial", "center": [0.3, 0.5], "rx": 0.12, "ry": 0.12}));
+    exec(&mut h, "mask.add", json!({"kind": "radial", "center": [0.7, 0.5], "rx": 0.12, "ry": 0.12}));
+    exec(&mut h, "view.maskOverlayAll", json!({}));
+    assert!(h.app.ui.mask_overlay_all);
+    assert_eq!(h.app.session.active_mask, Some(2));
+    // Pins add their own <maskPin:…> elements; keep them out of the handle count.
+    exec(&mut h, "view.maskPins", json!({"show": false}));
+    h.settle(SETTLE);
+
+    let handles_of = |h: &Headless, id: usize| h.app.widgets.iter().filter(|(w, _)| w.starts_with(&format!("maskHandle:{id}:"))).count();
+    // The selected mask keeps its 4 edge handles and its rotation grip.
+    assert_eq!(handles_of(&h, 2), 5, "the selected mask keeps its handles");
+    // The other visible mask draws its outline but registers no handle: it is not draggable.
+    assert_eq!(handles_of(&h, 1), 0, "an unselected mask must not become draggable");
+    // …while a mask with no components has nothing to outline and nothing to grab either.
+    exec(&mut h, "mask.add", json!({"kind": "luminanceRange"}));
+    exec(&mut h, "mask.addComponent", json!({"kind": "radial", "op": "add", "center": [0.5, 0.8], "rx": 0.08, "ry": 0.08}));
+    assert_eq!(h.app.session.active_mask, Some(3));
+    assert_eq!(handles_of(&h, 1), 0);
+    h.settle(SETTLE);
+}
+
+/// #2210: the outlines of *unselected* masks are painted, not registered as widgets, so the way to
+/// observe them is the rendered pixels. With the all-masks overlay on, the unselected mask's
+/// ellipse edge must carry white stroke pixels the photo alone does not have.
+#[test]
+fn all_masks_overlay_paints_the_outline_of_an_unselected_mask() {
+    let mut h = detail("panel.masking");
+    exec(&mut h, "mask.add", json!({"kind": "radial", "center": [0.3, 0.5], "rx": 0.12, "ry": 0.12}));
+    exec(&mut h, "mask.add", json!({"kind": "radial", "center": [0.7, 0.5], "rx": 0.12, "ry": 0.12}));
+    assert_eq!(h.app.session.active_mask, Some(2));
+    exec(&mut h, "view.maskPins", json!({"show": false}));
+
+    // Sample the whole canvas: the outline is white (alpha 170) over the photo, so the overlay adds
+    // near-white pixels along the unselected mask's ellipse edge.
+    let white_pixels = |h: &mut Headless, on: bool| -> usize {
+        let overlay = h.app.ui.mask_overlay_all;
+        if overlay != on {
+            exec(h, "view.maskOverlayAll", json!({}));
+        }
+        assert_eq!(h.app.ui.mask_overlay_all, on);
+        h.settle(SETTLE);
+        let px = h.view.paint(&Default::default());
+        px.pixels.iter().filter(|p| p.r() > 200 && p.g() > 200 && p.b() > 200).count()
+    };
+    let off = white_pixels(&mut h, false);
+    let on = white_pixels(&mut h, true);
+    assert!(on > off, "the unselected mask's outline must add white pixels: off {off}, on {on}");
+}
+
 /// #518: holding the brush still, however long, paints the same feathered spot as a quick press.
 #[test]
 fn holding_the_brush_still_does_not_harden_the_spot() {