Section Analysis in the browser, with an eye to turn it off (#822) (#947)

A section stayed on with nothing in the browser to switch it off; only the
viewport's context menu had Remove Section. While there is one, the browser
now has an Analysis folder listing it. Its eye (and the folder's) hides the
section and shows it again on the same plane; a double-click or Edit Section
Analysis opens the dialog, and Delete removes it. Browser rows with an eye
publish an `eye:<label>` handle for automation.

Fixes #822

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

crates/ui-egui/src/browser.rs

@@ -62,6 +62,9 @@ pub struct TreeState {
     pub timeline_anchor: Option<String>,
     /// The Edit Canvas / Calibrate panel.
     pub canvas_panel: Option<CanvasPanel>,
+    /// A Section Analysis hidden with its eye in the Analysis folder: its plane (origin,
+    /// normal), so the eye can bring it back (#822).
+    pub hidden_section: Option<(solidcraft_engine::geom::Vec3, solidcraft_engine::geom::Vec3)>,
     /// What waits for the Capture Position question: a command id, or [`SAVE`].
     pub capture_prompt: Option<String>,
     /// The last row clicked (for Shift ranges).
@@ -354,6 +357,7 @@ pub(crate) fn draw_row(ui: &mut egui::Ui, id: egui::Id, row: &Row) -> RowResp {
             ui.painter().line_segment([er.left_bottom() + vec2(2.0, -2.0), er.right_top() + vec2(-2.0, 2.0)], Stroke::new(1.4, t.text_dim));
         }
         out.eye = resp.clicked() && click_on == 2;
+        crate::scenario::publish_handle(&format!("eye:{}", row.label), er.center());
     }
     x += 18.0;
     // Activation radio (components).
@@ -680,6 +684,7 @@ fn component_rows(app: &mut SolveApp, ui: &mut egui::Ui, id: u64, depth: usize,
         named_view_rows(app, ui, d, acts);
         origin_rows(app, ui, d);
         canvas_rows(app, ui, d, acts);
+        analysis_rows(app, ui, d, acts);
     }
     let _ = t;
     for folder in ["bodies", "sketches", "construction"] {
@@ -952,6 +957,77 @@ pub fn view_items(app: &SolveApp, name: &str) -> Vec<Item> {
     ]
 }
 
+/// The Analysis folder: the Section Analysis, while there is one (shown or hidden), with an eye
+/// to hide and show it, a double-click to edit it and a menu to delete it (#822).
+fn analysis_rows(app: &mut SolveApp, ui: &mut egui::Ui, depth: usize, acts: &mut Actions) {
+    if app.session.section.is_some() {
+        // A section made (or remade) while an older one was hidden replaces it.
+        app.tree.hidden_section = None;
+    }
+    let visible = app.session.section.is_some();
+    if !visible && app.tree.hidden_section.is_none() {
+        return;
+    }
+    let key = "analysis";
+    let open = is_open(app, key, true);
+    let r = draw_row(
+        ui,
+        ui.id().with(key),
+        &Row { depth, fold: Some(open), eye: Some(visible), icon: "folder", label: "Analysis", ..Default::default() },
+    );
+    if r.fold || r.clicked {
+        toggle(app, key, true);
+    }
+    if r.eye {
+        set_section_visible(app, !visible);
+    }
+    if !open {
+        return;
+    }
+    let r = draw_row(
+        ui,
+        ui.id().with("section_analysis"),
+        &Row { depth: depth + 1, eye: Some(visible), icon: "section", label: "Section Analysis", dim: !visible, ..Default::default() },
+    );
+    if r.eye {
+        set_section_visible(app, !visible);
+    }
+    if r.double {
+        app.start("inspect.section");
+    }
+    if let Some(p) = r.secondary {
+        acts.menu = Some((p, Target::Section));
+    }
+}
+
+/// Hide the Section Analysis (keeping its plane to show it again) or show the hidden one.
+pub fn set_section_visible(app: &mut SolveApp, visible: bool) {
+    if visible {
+        if let Some((origin, normal)) = app.tree.hidden_section {
+            let plane = json!({"origin": [origin.x, origin.y, origin.z], "normal": [normal.x, normal.y, normal.z]});
+            if app.run("inspect.section", json!({ "plane": plane })).is_ok() {
+                app.tree.hidden_section = None;
+            }
+        }
+    } else if let Some(section) = app.session.section
+        && app.run("inspect.section", json!({"clear": true})).is_ok()
+    {
+        app.tree.hidden_section = Some(section);
+    }
+}
+
+/// The menu of the Section Analysis row.
+pub fn section_items(app: &SolveApp) -> Vec<Item> {
+    let visible = app.session.section.is_some();
+    vec![
+        Item::action("ui.editSection", "Edit Section Analysis", "section"),
+        Item::sep(),
+        Item::action("ui.unsection", "Delete", "delete"),
+        Item::sep(),
+        Item::action("ui.sectionVisible", "Show/Hide", "eye").key("V").with(json!({ "visible": !visible })),
+    ]
+}
+
 /// The Canvases folder (reference images) with an eye per canvas.
 fn canvas_rows(app: &mut SolveApp, ui: &mut egui::Ui, depth: usize, acts: &mut Actions) {
     let canvases: Vec<(u64, String, bool)> = app.session.doc.canvases.iter().map(|c| (c.id, c.name.clone(), c.visible)).collect();
@@ -1883,3 +1959,7 @@ fn occurrence_origin(app: &SolveApp, occurrence: u64) -> Option<solidcraft_engin
     let own = app.session.pending_moves.get(&occurrence).copied().unwrap_or(o.transform);
     Some(solidcraft_engine::doc::apply_point(&solidcraft_engine::doc::mat_mul(&parent, &own), solidcraft_engine::geom::Vec3::ZERO))
 }
+
+#[cfg(test)]
+#[path = "section_browser_tests.rs"]
+mod section_browser_tests;