feat(core): add a property catalog and derive its discovery channels

crates/app/src/ui/canvas/interactions.rs

@@ -256,7 +256,7 @@ pub(crate) fn handle_data_tool_target(
         .and_then(|o| o.plot())
         .is_some()
     {
-        select_object_datasets(app, ci, id);
+        app.focus_object_datasets(ci, id);
     }
 }
 
@@ -309,7 +309,7 @@ pub(crate) fn handle_object_interactions(
                 if matches!(app.interaction(), Interaction::PanelLabel(_)) {
                     app.reset_interaction();
                 }
-                select_object_datasets(app, ci, id);
+                app.focus_object_datasets(ci, id);
                 if let Some(object) = app.doc.canvases[ci].object(id).filter(|o| !o.locked) {
                     let before = object.frame;
                     let start = page_pos.map(|p| [p.x, p.y]).unwrap_or([before.x, before.y]);
@@ -477,23 +477,6 @@ fn finish_marquee(app: &mut PlotxApp, ci: usize, marq: MarqueeDrag) {
     );
 }
 
-fn select_object_datasets(app: &mut PlotxApp, ci: usize, id: ObjectId) {
-    let Some(object) = app.doc.canvases[ci].object(id) else {
-        return;
-    };
-    let active = object.dataset().and_then(|id| app.doc.dataset_index(id));
-    let datasets = object
-        .dataset_ids()
-        .into_iter()
-        .filter_map(|id| app.doc.dataset_index(id))
-        .collect::<Vec<_>>();
-    if !datasets.is_empty() {
-        app.focus_datasets(&datasets, active);
-    } else {
-        app.set_active_dataset(active);
-    }
-}
-
 pub(crate) fn arrange_context_menu(app: &mut PlotxApp, ci: usize, ui: &mut Ui) {
     if ui.button("Copy figure").clicked() {
         let ctx = ui.ctx().clone();
@@ -578,6 +561,10 @@ pub(crate) fn arrange_context_menu(app: &mut PlotxApp, ci: usize, ui: &mut Ui) {
     if ui.checkbox(&mut snap, "Snap to grid & objects").clicked() {
         app.set_snap_enabled(snap);
     }
+    // Channel 4: whatever the selection draws, its settings are one click from
+    // here. Navigation only — the entries jump to the panel section that owns
+    // the controls, and are derived from the catalog rather than listed again.
+    crate::ui::properties::discovery::context_menu(app, ui);
     ui.separator();
     if ui.button("Canvas settings…").clicked() {
         app.session.ui.canvas_settings = Some(ci);

crates/app/src/ui/canvas/mod.rs

@@ -39,6 +39,7 @@ mod painting;
 mod panel_notes;
 mod peaks;
 mod phase;
+mod readout;
 mod regions;
 mod slices;
 mod snap;
@@ -57,6 +58,7 @@ pub(crate) use painting::*;
 pub(crate) use panel_notes::*;
 pub(crate) use peaks::*;
 pub(crate) use phase::*;
+pub(crate) use readout::*;
 pub(crate) use regions::*;
 pub(crate) use slices::*;
 pub(crate) use snap::*;
@@ -229,6 +231,7 @@ pub fn render_central(app: &mut PlotxApp, ui: &mut Ui) {
     paint_marquee(app, ci, rect, &painter, chrome);
     paint_panel_label_selection(app, ci, rect, &painter, chrome);
     paint_object_selection(app, ci, rect, page, &painter, chrome);
+    paint_property_readouts(app, ci, rect, &painter, chrome, ui.visuals().dark_mode);
     paint_tile_ghost(app, &painter, chrome);
     paint_tile_preview(app, rect, &painter, chrome);
     super::canvas_size::page_size_chrome(app, ci, page, rect, ui);

crates/app/src/ui/canvas/readout.rs

@@ -0,0 +1,77 @@
+//! The in-place readout for canvas-steppable settings (§8.5 channel 3).
+//!
+//! "The best parameter is the one you never have to look for" only holds if the
+//! plot says what its threshold currently is. This paints that value in the
+//! corner of every plot the `+` / `-` gesture would act on, so the number the
+//! keys move is visible where the keys are pressed.
+//!
+//! It is a label and nothing more: it reads a cached value through
+//! [`PlotxApp::contour_base_readout`] and never resolves, measures or queues
+//! anything. A plot whose estimate has not arrived says so.
+
+use super::{object_screen_rect, plot_rect};
+use crate::ui::properties;
+use egui::{Align2, Color32, FontId};
+use plotx_core::state::PlotxApp;
+
+const READOUT_FONT_PT: f32 = 11.0;
+const READOUT_INSET_PX: f32 = 6.0;
+
+/// Paint the corner readout for each plot the canvas gesture currently targets.
+pub(crate) fn paint_property_readouts(
+    app: &PlotxApp,
+    ci: usize,
+    rect: egui::Rect,
+    painter: &egui::Painter,
+    chrome: super::ChromeStyle,
+    dark_mode: bool,
+) {
+    // Nothing to read out unless a steppable property applies right now — the
+    // same condition that enables the gesture, asked once, so the label cannot
+    // appear on a plot the keys would not move.
+    let Some((property, _)) = properties::discovery::step_target(app) else {
+        return;
+    };
+    let Some(canvas) = app.doc.canvases.get(ci) else {
+        return;
+    };
+    for object in properties::discovery::selection_objects(app) {
+        // The series the gesture edits, not the first one the plot happens to
+        // hold. A contour stacked over a heatmap is drawn second, and reading
+        // the first series would caption the plot with a heatmap that has no
+        // level while the keys moved the contour that does — or, with several
+        // contours, present one of them as the whole plot's threshold.
+        let targets = app.series_targets(ci, object);
+        let readouts: Vec<_> = app
+            .resolve_property_set(property, &targets)
+            .applicable_targets
+            .iter()
+            .filter_map(|address| app.contour_base_readout(&address.target))
+            .collect();
+        let Some(text) = properties::readout::aggregate_summary(&readouts) else {
+            continue;
+        };
+        let Some(frame) = object_screen_rect(app.session.board, canvas, object, rect) else {
+            continue;
+        };
+        let frame = plot_rect(frame);
+        if !frame.is_positive() {
+            continue;
+        }
+        let anchor = frame.right_top() + egui::vec2(-READOUT_INSET_PX, READOUT_INSET_PX);
+        let galley = painter.layout_no_wrap(
+            text,
+            FontId::proportional(READOUT_FONT_PT),
+            chrome.selection_stroke,
+        );
+        let text_rect = Align2::RIGHT_TOP.anchor_size(anchor, galley.size());
+        // A plot's own ink runs right up to its frame, so the label needs a
+        // backing plate to stay legible over dense contours.
+        painter.rect_filled(
+            text_rect.expand(3.0),
+            3.0,
+            Color32::from_black_alpha(if dark_mode { 150 } else { 20 }),
+        );
+        painter.galley(text_rect.min, galley, chrome.selection_stroke);
+    }
+}

crates/app/src/ui/command_exec.rs

@@ -144,6 +144,21 @@ pub fn execute(
                 app.apply_theme(&theme);
             }
         }
+        // Channels 2 and 4 navigate; they never edit. `reveal_property` opens
+        // the home the presentation names and asks the panel to scroll and
+        // highlight — the same route a palette hit takes.
+        CommandId::PropertyGroup(section) => {
+            let now = ctx.input(|input| input.time);
+            if let Some(property) = super::properties::discovery::entry_property(
+                section,
+                super::properties::PRESENTATIONS,
+            ) {
+                super::command_palette::reveal_property(app, property, now);
+                ctx.request_repaint();
+            }
+        }
+        // Channel 3 edits, and does so through the property planner.
+        CommandId::StepProperty(step) => super::properties::discovery::step_selection(app, step),
         CommandId::Tool(tool) => app.toggle_tool(tool),
     }
 }
@@ -203,8 +218,7 @@ fn open_chart_type(app: &mut PlotxApp) {
     let Some((ci, object)) = commands::chart_plot_target(app, dataset) else {
         return;
     };
-    app.session.active_canvas = Some(ci);
-    app.select_object(ci, object);
+    app.reveal_object(ci, object);
     app.session.secondary_sidebar_visible = true;
 }