feat(globe): render the tilt and north-up buttons from the globe actions store

The camera orientation controls publish whether the map is tilted and the
camera's whole-degree heading instead of writing the buttons' attributes,
and answer tilt and north-up through the globe actions store. The new
GlobeCompass renders the heading, so a rotating camera re-renders only the
compass. The store drops an unchanged camera state and keeps each clear
owner's busy state, so the buttons show the shell that answers them: a
shell replaced by a newer one, or disposed mid-clear, leaves the live
shell's state alone, and an older shell that answers again shows its own.
createOwners gains owns() and ownerOf().

CHANGELOG.md

@@ -72,8 +72,9 @@
   are the kit's new `UiChip`. The selects are the kit's new `UiSelect`, the
   status badges its new `UiBadge` and the one-line empty states its new
   `UiEmpty`.
-  The top-center clear and share buttons call the shell through the new
-  globe actions store. `syncScopeControls` (`./ui/display`),
+  The top-center clear, share, tilt and north-up buttons call the shell
+  through the new globe actions store, which also carries the camera's tilt
+  and compass heading. `syncScopeControls` (`./ui/display`),
   `shouldHideCollapsedRightPanels` (`./ui/layout`) and
   `bindClearLayersControl` (`./ui/layers`) are deprecated: the Display view,
   the rail and the globe actions view now own what they did. `./ui/input` imports Vue

docs/VUE-MIGRATION.md

@@ -226,9 +226,13 @@ a feature supplying only its accent.
    renders what each owner's `createToast()` publishes there, on that
    owner's own timer, and the title bar's FPS readout what
    `createFrameRateMonitor()` publishes), the globe actions (in progress:
-   `GlobeActions` renders the top-center bar; its clear and share buttons
-   call the shell through the `gev-globe-actions` store, which also carries
-   a clear under way), the Scene actions panel (`SceneInteractions`
+   `GlobeActions` renders the top-center bar; its clear, share, tilt and
+   north-up buttons call the shell through the `gev-globe-actions` store,
+   which also carries a clear under way and the camera's tilt and heading
+   that `bindCameraOrientationControls` publishes each drawn frame it
+   changes, which only `GlobeCompass` renders; an owner publishes only
+   while it answers the button, so a shell replaced by a newer one leaves
+   its state alone), the Scene actions panel (`SceneInteractions`
    teleports what the scene interactions owner publishes to the
    `gev-scene-interactions` store into the viewer's container; the owner
    keeps the pick handler and focuses the picked action), the data-pack

scripts/package-boundaries.json

@@ -140,7 +140,8 @@
       "src/ui/kit/UiEmpty.vue",
       "src/ui/kit/UiBadge.vue",
       "src/ui/stores/globeActions.js",
-      "src/ui/views/panels/GlobeActions.vue"
+      "src/ui/views/panels/GlobeActions.vue",
+      "src/ui/views/panels/GlobeCompass.vue"
     ],
     "external": ["vue", "pinia"]
   },

src/sharelink.celestial.test.mjs

@@ -788,8 +788,7 @@ test('visual input listeners are revoked before asynchronous UI teardown', () =>
   assert.match(synchronous, /this\._displayBindings\.destroy\(\)/);
   assert.match(synchronous, /this\._visualSettings\.stop\(\)/);
   assert.match(synchronous, /this\._mapSourceControls\?\.destroy\(\)/);
-  assert.match(synchronous, /globeActions\.detach\(this\._clearLayersToken\)/);
-  assert.match(synchronous, /globeActions\.detach\(this\._shareToken\)/);
+  assert.match(synchronous, /this\._releaseGlobeActions\(\)/);
   assert.match(synchronous, /this\._locationNavigation\.destroy\(\)/);
   assert.match(LocationNavigation.prototype.destroy.toString(), /this\._locationControls\?\.destroy\(\)/);
   assert.match(LocationNavigation.prototype.destroy.toString(), /this\._locationLookup\?\.destroy\(\)/);

src/ui/applicationShell.js

@@ -1008,10 +1008,7 @@ export class StyleManager extends ShellFacade {
         showToast: (message) => {
           if (!this._disposed) this._showToast(message);
         },
-        setClearBusy: (busy) => {
-          if (!this._disposed)
-            useGlobeActionsStore(applicationPinia()).publishClearBusy(busy);
-        },
+        setClearBusy: (busy) => this._publishClearBusy(busy),
       },
     });
     // The Contacts layer publishes its panel; the view calls its navigation.
@@ -1633,21 +1630,64 @@ export class StyleManager extends ShellFacade {
         if (!this._disposed) void this.clearSelectedLayers();
       },
     });
+    // A clear under way as the shell connects again stays on the button.
+    if (this._clearBusy != null)
+      store.publishClearBusy(this._clearLayersToken, this._clearBusy);
+  }
+
+  /**
+   * Publish this shell's clear under way; the button shows it while this
+   * shell answers the clear.
+   */
+  _publishClearBusy(busy) {
+    if (this._disposed) return;
+    this._clearBusy = Boolean(busy);
+    if (this._clearLayersToken)
+      useGlobeActionsStore(applicationPinia()).publishClearBusy(
+        this._clearLayersToken,
+        busy,
+      );
+  }
+
+  /**
+   * Stop answering the globe actions. Its clear under way goes with its
+   * owner, and its camera state too; a newer shell's stays.
+   */
+  _releaseGlobeActions() {
+    const store = useGlobeActionsStore(applicationPinia());
+    if (store.owns(this._orientationToken, 'tilt')) store.publishCamera(null);
+    if (this._clearLayersToken) store.detach(this._clearLayersToken);
+    if (this._shareToken) store.detach(this._shareToken);
+    if (this._orientationToken) store.detach(this._orientationToken);
+    this._clearLayersToken = this._shareToken = this._orientationToken = null;
   }
 
   /** Wire Google Maps-style tilt and north-up camera actions. */
   _initCameraOrientationControls() {
+    const store = useGlobeActionsStore(applicationPinia());
     this._cameraOrientationControls?.destroy();
-    this._cameraOrientationControls = bindCameraOrientationControls({
+    if (this._orientationToken) store.detach(this._orientationToken);
+    const token = store.connect({
+      tilt: () => controls.tilt(),
+      northUp: () => controls.northUp(),
+    });
+    this._orientationToken = token;
+    // A newer shell's controls own what the buttons show.
+    const controls = bindCameraOrientationControls({
       viewer: this.viewer,
-      elements: {
-        tiltButton: this._tiltMapBtn,
-        northButton: this._northUpBtn,
+      // Every drawn frame publishes: a state the store already shows stops
+      // here, before the store's actions run.
+      publish: (state) => {
+        const shown = store.camera;
+        if (shown?.tilted === state.tilted && shown.heading === state.heading)
+          return;
+        if (store.owns(token, 'tilt')) store.publishCamera(state);
       },
       runNavigation: (noun, navigate) =>
         this._navigation.runOrientation(noun, navigate),
       showToast: (message) => this._showToast(message),
     });
+    this._cameraOrientationControls = controls;
   }
 
   // ── Share Button ─────────────────────────────
@@ -1790,12 +1830,7 @@ export class StyleManager extends ShellFacade {
     useDisplayStore(applicationPinia()).connectMapSource(null);
     useDisplayStore(applicationPinia()).publishMapSource(null);
     this._cameraOrientationControls?.destroy();
-    const globeActions = useGlobeActionsStore(applicationPinia());
-    if (this._clearLayersToken) globeActions.detach(this._clearLayersToken);
-    if (this._shareToken) globeActions.detach(this._shareToken);
-    this._clearLayersToken = this._shareToken = null;
-    // A clear this shell leaves running must not keep the next shell's bar busy.
-    globeActions.publishClearBusy(null);
+    this._releaseGlobeActions();
     this._cctvControls?.destroy();
     this.services?.streetLevelLayer?.attachNavigation?.(null);
     this._streetLevelControls?.destroy();

src/ui/cameraOrientationControls.js

@@ -239,18 +239,20 @@ export function createCameraOrientationAnimator(
   };
 }
 
-/** Bind the two map-orientation actions and keep their accessible state current. */
+/**
+ * Answer the two map-orientation actions and publish the state their buttons
+ * show: whether the map is tilted and the camera's whole-degree heading.
+ * The state is published on every rendered frame; its store keeps only a
+ * change, so an owner that takes the buttons back shows its state at once.
+ */
 export function bindCameraOrientationControls({
   viewer,
-  elements,
+  publish,
   runNavigation,
   showToast,
 }) {
-  const tiltButton = elements?.tiltButton;
-  const northButton = elements?.northButton;
   const removers = [];
   let destroyed = false;
-  let applied = null;
   // The tilt state is the one thing here that costs a depth read of the middle
   // of the screen: 4 ms median and up to 12 ms, measured on this machine. It is
   // therefore held between refreshes rather than recomputed per frame.
@@ -265,12 +267,14 @@ export function bindCameraOrientationControls({
   };
 
   /**
-   * Write the two controls' state, but only what actually changed.
+   * Publish the two controls' state.
    *
    * The compass needle reads the camera's own bearing, which costs nothing, so
    * this can run on every rendered frame: measured at 1.4 ms across 120 frames
    * of a continuously dragged map (0.012 ms per frame, 0.1 ms worst case),
    * against the 4 ms per frame the depth read it replaced would have cost.
+   * That measured the controls' own work; what a publish renders is the
+   * view's (the globe actions compass alone renders the heading).
    */
   function sync() {
     if (destroyed) return;
@@ -278,40 +282,11 @@ export function bindCameraOrientationControls({
       tilted,
       heading: Math.round(headingDegrees(viewer?.camera)) % 360,
     };
-    if (
-      applied &&
-      applied.tilted === next.tilted &&
-      applied.heading === next.heading
-    )
-      return;
-    if (!applied || applied.tilted !== next.tilted) {
-      tiltButton?.setAttribute('aria-pressed', String(next.tilted));
-      tiltButton?.setAttribute(
-        'aria-label',
-        next.tilted
-          ? t('Return map to straight-down view')
-          : t('Tilt map to oblique view'),
-      );
-    }
-    if (!applied || applied.heading !== next.heading) {
-      northButton?.setAttribute('data-north-up', String(next.heading === 0));
-      northButton?.style?.setProperty('--camera-heading', `${next.heading}deg`);
-      northButton?.setAttribute(
-        'aria-label',
-        t('Reset map to north up. Current heading {heading} degrees', {
-          heading: next.heading,
-        }),
-      );
-    }
-    applied = next;
+    publish?.(next);
   }
 
-  const listen = (element, handler) => {
-    if (!element) return;
-    element.addEventListener('click', handler);
-    removers.push(() => element.removeEventListener('click', handler));
-  };
-  listen(tiltButton, () => {
+  function tilt() {
+    if (destroyed) return;
     const pending = animator.destination;
     const result = runNavigation('camera', () => {
       const frame = readCameraTargetFrame(viewer);
@@ -332,8 +307,10 @@ export function bindCameraOrientationControls({
       tilted = result.tilted;
     }
     sync();
-  });
-  listen(northButton, () => {
+  }
+
+  function northUp() {
+    if (destroyed) return;
     const pending = animator.destination;
     const result = runNavigation('camera', () => {
       const frame = readCameraTargetFrame(viewer);
@@ -347,7 +324,7 @@ export function bindCameraOrientationControls({
     });
     if (result) showToast?.(t('North up'));
     sync();
-  });
+  }
 
   const subscribe = (event, handler) => {
     const remove = event?.addEventListener?.(handler);
@@ -369,6 +346,8 @@ export function bindCameraOrientationControls({
   refreshTilt();
 
   return {
+    tilt,
+    northUp,
     sync,
     refreshTilt,
     cancel: animator.cancel,

src/ui/cameraOrientationControls.test.mjs

@@ -49,23 +49,25 @@ function createViewer({ cameraPosition, target, pickPosition = null } = {}) {
   return { viewer, calls, target: surface };
 }
 
-class FakeButton extends EventTarget {
-  constructor() {
-    super();
-    this.attributes = new Map();
-    this.style = {
-      setProperty: (name, value) => this.attributes.set(name, value),
-    };
-  }
-  setAttribute(name, value) {
-    this.attributes.set(name, String(value));
-  }
-  getAttribute(name) {
-    return this.attributes.get(name);
-  }
-  click() {
-    this.dispatchEvent(new Event('click'));
-  }
+/**
+ * Record what the controls publish as the globe actions store keeps it:
+ * `state` is the latest, and `publishes` counts the changes.
+ */
+function recorder() {
+  const bar = {
+    state: null,
+    publishes: 0,
+    publish(state) {
+      if (
+        bar.state?.tilted === state.tilted &&
+        bar.state?.heading === state.heading
+      )
+        return;
+      bar.state = state;
+      bar.publishes += 1;
+    },
+  };
+  return bar;
 }
 
 /**
@@ -277,29 +279,29 @@ test('the button shows the state the next click will produce, at every range', (
   for (const range of [3_000, 18_000_000]) {
     const { viewer } = createRealViewer(AUSTIN_GROUND);
     orbit(viewer, AUSTIN_GROUND, 0, STRAIGHT_DOWN_PITCH, range);
-    const tiltButton = new FakeButton();
+    const bar = recorder();
     const controls = bindCameraOrientationControls({
       viewer,
-      elements: { tiltButton, northButton: new FakeButton() },
+      publish: bar.publish,
       runNavigation: (_noun, navigate) => navigate(),
     });
 
     assert.equal(
-      tiltButton.getAttribute('aria-pressed'),
-      'false',
+      bar.state.tilted,
+      false,
       `straight down at ${range} m must not read as tilted`,
     );
-    tiltButton.click();
+    controls.tilt();
     assert.equal(
-      tiltButton.getAttribute('aria-pressed'),
-      'true',
+      bar.state.tilted,
+      true,
       `after one click at ${range} m the button must read tilted`,
     );
     // And the exact refresh that runs when the camera settles must agree.
     controls.refreshTilt();
     assert.equal(
-      tiltButton.getAttribute('aria-pressed'),
-      'true',
+      bar.state.tilted,
+      true,
       `the settled state at ${range} m must agree with the commanded one`,
     );
     controls.destroy();
@@ -309,13 +311,13 @@ test('the button shows the state the next click will produce, at every range', (
 test('the needle follows a rotation too small for the camera-changed threshold', () => {
   const { viewer } = createRealViewer(AUSTIN_GROUND);
   orbit(viewer, AUSTIN_GROUND, 0, Cesium.Math.toRadians(-80), 5_000);
-  const northButton = new FakeButton();
+  const bar = recorder();
   const controls = bindCameraOrientationControls({
     viewer,
-    elements: { tiltButton: new FakeButton(), northButton },
+    publish: bar.publish,
     runNavigation: (_noun, navigate) => navigate(),
   });
-  assert.equal(northButton.getAttribute('--camera-heading'), '0deg');
+  assert.equal(bar.state.heading, 0);
 
   // Ten degrees is far below Cesium's default percentageChanged, so
   // `camera.changed` may never fire for it; the per-frame signal must.
@@ -326,23 +328,23 @@ test('the needle follows a rotation too small for the camera-changed threshold',
   orbit(viewer, AUSTIN_GROUND, 10, Cesium.Math.toRadians(-80), 5_000);
   viewer.scene.preRender.raiseEvent();
   assert.equal(
-    northButton.getAttribute('--camera-heading'),
-    '10deg',
+    bar.state.heading,
+    10,
     `needle must follow a 10 degree rotation (camera.changed fired ${changedFired} time(s))`,
   );
 
   orbit(viewer, AUSTIN_GROUND, 13, Cesium.Math.toRadians(-80), 5_000);
   viewer.scene.preRender.raiseEvent();
-  assert.equal(northButton.getAttribute('--camera-heading'), '13deg');
+  assert.equal(bar.state.heading, 13);
   controls.destroy();
 });
 
 test('north-up indicator follows real heading including the 360-degree seam', () => {
   const { viewer } = createRealViewer(AUSTIN_GROUND);
-  const northButton = new FakeButton();
+  const bar = recorder();
   const controls = bindCameraOrientationControls({
     viewer,
-    elements: { northButton },
+    publish: bar.publish,
     runNavigation: (_noun, navigate) => navigate(),
   });
   for (const [heading, active] of [
@@ -355,66 +357,49 @@ test('north-up indicator follows real heading including the 360-degree seam', ()
   ]) {
     orbit(viewer, AUSTIN_GROUND, heading, Cesium.Math.toRadians(-80), 5_000);
     viewer.scene.preRender.raiseEvent();
-    assert.equal(
-      northButton.getAttribute('data-north-up'),
-      String(active),
-      `heading ${heading}`,
-    );
+    assert.equal(bar.state.heading === 0, active, `heading ${heading}`);
   }
   controls.destroy();
 });
 
-test('a settled camera writes nothing, and teardown releases every signal', () => {
+test('a settled camera publishes no change, and teardown releases every signal', () => {
   const { viewer } = createRealViewer(AUSTIN_GROUND);
   orbit(viewer, AUSTIN_GROUND, 0, Cesium.Math.toRadians(-80), 5_000);
-  const tiltButton = new FakeButton();
-  const northButton = new FakeButton();
-  let writes = 0;
-  const count = (element) => {
-    const setAttribute = element.setAttribute.bind(element);
-    const setProperty = element.style.setProperty.bind(element.style);
-    element.setAttribute = (name, value) => {
-      writes += 1;
-      setAttribute(name, value);
-    };
-    element.style.setProperty = (name, value) => {
-      writes += 1;
-      setProperty(name, value);
-    };
-  };
-  count(tiltButton);
-  count(northButton);
-
+  const bar = recorder();
   const preRenderBefore = viewer.scene.preRender.numberOfListeners;
   const moveEndBefore = viewer.camera.moveEnd.numberOfListeners;
   const controls = bindCameraOrientationControls({
     viewer,
-    elements: { tiltButton, northButton },
+    publish: bar.publish,
     runNavigation: (_noun, navigate) => navigate(),
   });
   assert.equal(viewer.scene.preRender.numberOfListeners, preRenderBefore + 1);
   assert.equal(viewer.camera.moveEnd.numberOfListeners, moveEndBefore + 1);
 
-  writes = 0;
+  bar.publishes = 0;
   for (let i = 0; i < 60; i += 1) viewer.scene.preRender.raiseEvent();
-  assert.equal(writes, 0, '60 frames of a settled camera write nothing');
+  assert.equal(
+    bar.publishes,
+    0,
+    '60 frames of a settled camera publish no change',
+  );
 
   orbit(viewer, AUSTIN_GROUND, 47, Cesium.Math.toRadians(-80), 5_000);
   viewer.scene.preRender.raiseEvent();
-  assert.ok(writes > 0, 'a rotated camera updates the needle');
-  writes = 0;
+  assert.ok(bar.publishes > 0, 'a rotated camera updates the needle');
+  bar.publishes = 0;
   for (let i = 0; i < 20; i += 1) viewer.scene.preRender.raiseEvent();
-  assert.equal(writes, 0, 'and then goes quiet again');
+  assert.equal(bar.publishes, 0, 'and then goes quiet again');
 
   controls.destroy();
   assert.equal(viewer.scene.preRender.numberOfListeners, preRenderBefore);
   assert.equal(viewer.camera.moveEnd.numberOfListeners, moveEndBefore);
-  writes = 0;
+  bar.publishes = 0;
   orbit(viewer, AUSTIN_GROUND, 120, Cesium.Math.toRadians(-80), 5_000);
   viewer.scene.preRender.raiseEvent();
   viewer.camera.moveEnd.raiseEvent();
-  tiltButton.click();
-  assert.equal(writes, 0, 'a destroyed binding writes nothing');
+  controls.tilt();
+  assert.equal(bar.publishes, 0, 'a destroyed binding publishes nothing');
 });
 
 test('a sky-facing camera yields no frame and both actions decline', () => {
@@ -487,13 +472,12 @@ test('north-up preserves target pitch and range', () => {
 
 test('bindings route both controls and release every listener on destroy', () => {
   const { viewer } = createViewer();
-  const tiltButton = new FakeButton();
-  const northButton = new FakeButton();
+  const bar = recorder();
   const navigations = [];
   const toasts = [];
   const controls = bindCameraOrientationControls({
     viewer,
-    elements: { tiltButton, northButton },
+    publish: bar.publish,
     runNavigation(noun, navigate) {
       navigations.push(noun);
       return navigate();
@@ -501,20 +485,20 @@ test('bindings route both controls and release every listener on destroy', () =>
     showToast: (message) => toasts.push(message),
   });
 
-  tiltButton.click();
-  northButton.click();
+  controls.tilt();
+  controls.northUp();
   assert.deepEqual(navigations, ['camera', 'camera']);
   assert.deepEqual(toasts, ['Tilted view', 'North up']);
   // The button shows the state the click just commanded, not a re-measurement.
-  assert.equal(tiltButton.getAttribute('aria-pressed'), 'true');
-  assert.equal(northButton.getAttribute('--camera-heading'), '90deg');
+  assert.equal(bar.state.tilted, true);
+  assert.equal(bar.state.heading, 90);
 
   viewer.camera.heading = -1e-12;
   controls.sync();
-  assert.equal(northButton.getAttribute('--camera-heading'), '0deg');
+  assert.equal(bar.state.heading, 0);
 
   controls.destroy();
-  tiltButton.click();
+  controls.tilt();
   assert.deepEqual(navigations, ['camera', 'camera']);
   assert.equal(STRAIGHT_DOWN_PITCH, Cesium.Math.toRadians(-89));
 });
@@ -663,22 +647,21 @@ test('rapid tilt presses reverse direction and north-up keeps the requested tilt
   const { viewer } = createRealViewer(target);
   orbit(viewer, target, 90, OBLIQUE_PITCH, 1000);
   viewer.scene.preUpdate = new Cesium.Event();
-  const tiltButton = new FakeButton();
-  const northButton = new FakeButton();
+  const bar = recorder();
   let controls;
   controls = bindCameraOrientationControls({
     viewer,
-    elements: { tiltButton, northButton },
+    publish: bar.publish,
     runNavigation: (_noun, navigate) => {
       controls.cancel();
       return navigate();
     },
   });
-  tiltButton.click();
-  tiltButton.click();
-  assert.equal(tiltButton.getAttribute('aria-pressed'), 'true');
-  tiltButton.click();
-  northButton.click();
+  controls.tilt();
+  controls.tilt();
+  assert.equal(bar.state.tilted, true);
+  controls.tilt();
+  controls.northUp();
   assert.equal(viewer.scene.preUpdate.numberOfListeners, 1);
   time = 650;
   viewer.scene.preUpdate.raiseEvent();

src/ui/globeActions.test.mjs

@@ -14,30 +14,71 @@ function mount(t) {
   const pinia = createPinia();
   const store = useGlobeActionsStore(pinia);
   const calls = [];
-  store.connect({
+  const token = store.connect({
     clear: () => calls.push('clear'),
     share: () => calls.push('share'),
+    tilt: () => calls.push('tilt'),
+    northUp: () => calls.push('northUp'),
   });
   const app = createApp(GlobeActions).use(pinia);
   app.mount(document.body.appendChild(document.createElement('div')));
   t.after(() => app.unmount());
-  return { calls, store };
+  return { calls, store, token };
 }
 const $ = (id) => document.getElementById(id);
 
-test('the clear and share buttons call their owners', (t) => {
+test('every button calls its owner', (t) => {
   const { calls } = mount(t);
   $('clear-selected-layers').click();
   $('share-btn').click();
-  assert.deepEqual(calls, ['clear', 'share']);
+  $('tilt-map-view').click();
+  $('north-up-view').click();
+  assert.deepEqual(calls, ['clear', 'share', 'tilt', 'northUp']);
+});
+
+test('the tilt and compass buttons show the published camera', async (t) => {
+  const { store } = mount(t);
+  const tilt = $('tilt-map-view');
+  const north = $('north-up-view');
+  assert.equal(tilt.getAttribute('aria-pressed'), 'false');
+  assert.equal(tilt.getAttribute('aria-label'), 'Tilt map to oblique view');
+  assert.equal(north.getAttribute('aria-label'), 'Reset map to north up');
+  assert.equal(north.hasAttribute('data-north-up'), false);
+  assert.equal(north.style.getPropertyValue('--camera-heading'), '');
+
+  store.publishCamera({ tilted: true, heading: 0 });
+  await nextTick();
+  assert.equal(tilt.getAttribute('aria-pressed'), 'true');
+  assert.equal(
+    tilt.getAttribute('aria-label'),
+    'Return map to straight-down view',
+  );
+  assert.equal(north.getAttribute('data-north-up'), 'true');
+  assert.equal(north.style.getPropertyValue('--camera-heading'), '0deg');
+
+  store.publishCamera({ tilted: false, heading: 47 });
+  await nextTick();
+  assert.equal(tilt.getAttribute('aria-pressed'), 'false');
+  assert.equal(north.getAttribute('data-north-up'), 'false');
+  assert.equal(north.style.getPropertyValue('--camera-heading'), '47deg');
+  assert.equal(
+    north.getAttribute('aria-label'),
+    'Reset map to north up. Current heading 47 degrees',
+  );
+
+  // A disposed shell hands the next one an unmeasured compass.
+  store.publishCamera(null);
+  await nextTick();
+  assert.equal(north.hasAttribute('data-north-up'), false);
+  assert.equal(north.style.getPropertyValue('--camera-heading'), '');
 });
 
 test('a clear under way marks the button busy and keeps it focusable', async (t) => {
-  const { store } = mount(t);
+  const { store, token } = mount(t);
   const clear = $('clear-selected-layers');
   assert.equal(clear.getAttribute('aria-label'), 'Clear selected data layers');
   assert.equal(clear.hasAttribute('aria-busy'), false);
-  store.publishClearBusy(true);
+  store.publishClearBusy(token, true);
   await nextTick();
   assert.equal(clear.getAttribute('aria-busy'), 'true');
   assert.equal(clear.getAttribute('aria-disabled'), 'true');
@@ -46,13 +87,24 @@ test('a clear under way marks the button busy and keeps it focusable', async (t)
     'Clearing selected data layers',
   );
   assert.equal(clear.disabled, false);
-  store.publishClearBusy(false);
+  store.publishClearBusy(token, false);
   await nextTick();
   assert.equal(clear.getAttribute('aria-busy'), 'false');
   assert.equal(clear.getAttribute('aria-label'), 'Clear selected data layers');
+  // The button shows the clear of the owner that answers it: a newer one's,
+  // then the older one's again once the newer goes.
+  store.publishClearBusy(token, true);
+  const newer = store.connect({ clear() {} });
+  await nextTick();
+  assert.equal(clear.hasAttribute('aria-busy'), false);
+  store.publishClearBusy(newer, false);
+  await nextTick();
+  assert.equal(clear.getAttribute('aria-busy'), 'false');
+  store.detach(newer);
+  await nextTick();
+  assert.equal(clear.getAttribute('aria-busy'), 'true');
   // A shell disposed mid-clear hands the next one a bar that is not busy.
-  store.publishClearBusy(true);
-  store.publishClearBusy(null);
+  store.detach(token);
   await nextTick();
   assert.equal(clear.hasAttribute('aria-busy'), false);
   assert.equal(clear.hasAttribute('aria-disabled'), false);
@@ -67,3 +119,14 @@ test('a detached owner no longer answers', (t) => {
   $('share-btn').click();
   assert.deepEqual(calls, ['newer share', 'share']);
 });
+
+test('the same camera state again changes nothing', () => {
+  const store = useGlobeActionsStore(createPinia());
+  store.publishCamera({ tilted: true, heading: 12 });
+  const kept = store.camera;
+  store.publishCamera({ tilted: true, heading: 12 });
+  assert.equal(store.camera, kept);
+  store.publishCamera({ tilted: true, heading: 13 });
+  assert.notEqual(store.camera, kept);
+  assert.deepEqual(store.camera, { tilted: true, heading: 13 });
+});

src/ui/shareButton.test.mjs

@@ -160,7 +160,7 @@ test('a host hook that answers without a promise, or throws, still gets a toast'
   }
 });
 
-test('the shell answers the globe bar’s share and clear until it is disposed', async () => {
+test('the shell answers the globe bar until it is disposed', async () => {
   const calls = [];
   const owner = {
     _disposed: false,
@@ -173,9 +173,130 @@ test('the shell answers the globe bar’s share and clear until it is disposed',
   store.act('share');
   store.act('clear');
   assert.deepEqual(calls, ['share', 'clear']);
+  // A newer shell answers, and owns the busy state, until it goes.
+  const newer = { _disposed: false, clearSelectedLayers: async () => {} };
+  StyleManager.prototype._initClearSelectedLayersButton.call(newer);
+  assert.equal(store.owns(owner._clearLayersToken, 'clear'), false);
+  store.detach(newer._clearLayersToken);
+  assert.equal(store.owns(owner._clearLayersToken, 'clear'), true);
   store.detach(owner._shareToken);
   store.detach(owner._clearLayersToken);
   store.act('share');
   store.act('clear');
   assert.deepEqual(calls, ['share', 'clear']);
 });
+
+test('the shell’s camera controls answer tilt and north-up and publish their state', () => {
+  const store = useGlobeActionsStore(applicationPinia());
+  const navigations = [];
+  const owner = {
+    viewer: { camera: { heading: 0 } },
+    _navigation: {
+      runOrientation: (noun, navigate) => {
+        navigations.push(noun);
+        return navigate();
+      },
+    },
+    _showToast() {},
+  };
+  StyleManager.prototype._initCameraOrientationControls.call(owner);
+  assert.deepEqual(store.camera, { tilted: false, heading: 0 });
+  store.act('tilt');
+  store.act('northUp');
+  assert.deepEqual(navigations, ['camera', 'camera']);
+
+  // Initialised again, the shell replaces its own owner.
+  const first = owner._orientationToken;
+  StyleManager.prototype._initCameraOrientationControls.call(owner);
+  assert.notEqual(owner._orientationToken, first);
+  assert.equal(store.owns(first, 'tilt'), false);
+  assert.equal(store.owns(owner._orientationToken, 'tilt'), true);
+
+  // A newer shell owns what the buttons show.
+  const newer = store.connect({ tilt() {} });
+  owner.viewer.camera.heading = Math.PI / 2;
+  owner._cameraOrientationControls.sync();
+  assert.deepEqual(store.camera, { tilted: false, heading: 0 });
+  store.detach(newer);
+  owner.viewer.camera.heading = Math.PI;
+  owner._cameraOrientationControls.sync();
+  assert.deepEqual(store.camera, { tilted: false, heading: 180 });
+  owner._cameraOrientationControls.destroy();
+  store.detach(owner._orientationToken);
+});
+
+test('a shell that goes after a newer one leaves the newer one’s bar state', () => {
+  const store = useGlobeActionsStore(applicationPinia());
+  const shellWith = () => {
+    const owner = {
+      _disposed: false,
+      viewer: { camera: { heading: 0 } },
+      _navigation: { runOrientation: (_noun, navigate) => navigate() },
+      _showToast() {},
+      clearSelectedLayers: async () => {},
+    };
+    StyleManager.prototype._initClearSelectedLayersButton.call(owner);
+    StyleManager.prototype._initCameraOrientationControls.call(owner);
+    return owner;
+  };
+  const older = shellWith();
+  const newer = shellWith();
+  newer.viewer.camera.heading = Math.PI / 2;
+  newer._cameraOrientationControls.sync();
+  StyleManager.prototype._publishClearBusy.call(newer, true);
+  StyleManager.prototype._publishClearBusy.call(older, false);
+  assert.equal(store.clearBusy, true);
+
+  older._cameraOrientationControls.destroy();
+  StyleManager.prototype._releaseGlobeActions.call(older);
+  assert.equal(store.clearBusy, true);
+  assert.deepEqual(store.camera, { tilted: false, heading: 90 });
+
+  // The shell that answers resets its state as it goes.
+  newer._cameraOrientationControls.destroy();
+  StyleManager.prototype._releaseGlobeActions.call(newer);
+  assert.equal(store.clearBusy, null);
+  assert.equal(store.camera, null);
+  // Its clear finishing after it went changes nothing.
+  newer._disposed = true;
+  StyleManager.prototype._publishClearBusy.call(newer, false);
+  assert.equal(store.clearBusy, null);
+});
+
+test('an older shell that answers again shows its clear and its unchanged camera', () => {
+  const store = useGlobeActionsStore(applicationPinia());
+  const shellWith = (heading) => {
+    const owner = {
+      _disposed: false,
+      viewer: { camera: { heading } },
+      _navigation: { runOrientation: (_noun, navigate) => navigate() },
+      _showToast() {},
+      clearSelectedLayers: async () => {},
+    };
+    StyleManager.prototype._initClearSelectedLayersButton.call(owner);
+    StyleManager.prototype._initCameraOrientationControls.call(owner);
+    return owner;
+  };
+  const older = shellWith(Math.PI / 2);
+  StyleManager.prototype._publishClearBusy.call(older, true);
+  const newer = shellWith(0);
+  // The newer shell's bar does not show the older one's clear.
+  assert.equal(store.clearBusy, null);
+  older._cameraOrientationControls.sync();
+  assert.deepEqual(store.camera, { tilted: false, heading: 0 });
+  // Initialised again mid-clear, a shell keeps its clear on the button.
+  StyleManager.prototype._publishClearBusy.call(newer, true);
+  StyleManager.prototype._initClearSelectedLayersButton.call(newer);
+  assert.equal(store.clearBusy, true);
+  StyleManager.prototype._publishClearBusy.call(newer, false);
+  newer._cameraOrientationControls.destroy();
+  StyleManager.prototype._releaseGlobeActions.call(newer);
+  assert.equal(store.camera, null);
+  // The older shell's clear is the button's again, and the next frame it
+  // draws puts its heading back.
+  assert.equal(store.clearBusy, true);
+  older._cameraOrientationControls.sync();
+  assert.deepEqual(store.camera, { tilted: false, heading: 90 });
+  older._cameraOrientationControls.destroy();
+  StyleManager.prototype._releaseGlobeActions.call(older);
+});

src/ui/shellElements.js

@@ -63,8 +63,6 @@ export function readShellElements(document = globalThis.document) {
     _cctvSourceBadge: document.getElementById('cctv-source-badge'),
     _cctvMeta: document.getElementById('cctv-meta'),
     _cctvSummary: document.getElementById('cctv-summary'),
-    _tiltMapBtn: document.getElementById('tilt-map-view'),
-    _northUpBtn: document.getElementById('north-up-view'),
     _resetGlobeBtn: document.getElementById('reset-globe-view'),
     _cockpitResetGlobeBtn: document.getElementById('cockpit-reset-globe'),
     _locationSearch: document.getElementById('location-search'),

src/ui/stores/globeActions.js

@@ -1,22 +1,82 @@
 import { defineStore } from 'pinia';
-import { ref } from 'vue';
+import { computed, ref, shallowReactive } from 'vue';
 import { createOwners } from './owners.js';
 
 /**
  * The top-center globe actions as their view renders them. The shell
- * publishes whether a clear of the selected data layers is under way, and
- * answers the clear and share buttons through act().
+ * publishes whether a clear of the selected data layers is under way and the
+ * camera's tilt and heading, and answers the buttons through act().
  */
 export const useGlobeActionsStore = defineStore('gev-globe-actions', () => {
-  /** Whether a clear is under way; null until the shell first says. */
-  const clearBusy = ref(null);
+  const owners = createOwners();
+  // Who answers which action, as the computed state below reads it.
+  const ownership = ref(0);
+  /** Each clear owner's clear under way, by its token. */
+  const busyBy = shallowReactive(new Map());
 
-  /** @param {boolean | null} busy null when no shell answers the clear. */
-  function publishClearBusy(busy) {
-    clearBusy.value = busy == null ? null : Boolean(busy);
+  /**
+   * Whether the clear owner's clear is under way; null until it says. Each
+   * owner keeps its own, so the button shows the one that answers it.
+   */
+  const clearBusy = computed(() => {
+    void ownership.value;
+    return busyBy.get(owners.ownerOf('clear')) ?? null;
+  });
+
+  /**
+   * @param {object} token The clear owner's, from connect().
+   * @param {boolean} busy
+   */
+  function publishClearBusy(token, busy) {
+    busyBy.set(token, Boolean(busy));
   }
 
-  const { connect, detach, act } = createOwners();
+  /**
+   * Whether the map reads as tilted and the camera's whole-degree heading;
+   * null until the camera controls first say.
+   * @type {import('vue').Ref<{ tilted: boolean, heading: number } | null>}
+   */
+  const camera = ref(null);
 
-  return { clearBusy, publishClearBusy, connect, detach, act };
+  /**
+   * Take the camera's state; the same state again changes nothing, so its
+   * owner can publish it on every frame the camera draws.
+   * @param {{ tilted: boolean, heading: number } | null} state
+   */
+  function publishCamera(state) {
+    const current = camera.value;
+    if (!state) {
+      camera.value = null;
+      return;
+    }
+    const tilted = Boolean(state.tilted);
+    if (current?.tilted === tilted && current.heading === state.heading) return;
+    camera.value = { tilted, heading: state.heading };
+  }
+
+  /** @param {Record<string, Function>} actions */
+  function connect(actions) {
+    const token = owners.connect(actions);
+    ownership.value += 1;
+    return token;
+  }
+
+  function detach(token) {
+    owners.detach(token);
+    busyBy.delete(token);
+    ownership.value += 1;
+  }
+
+  const { act, owns } = owners;
+
+  return {
+    clearBusy,
+    publishClearBusy,
+    camera,
+    publishCamera,
+    connect,
+    detach,
+    act,
+    owns,
+  };
 });

src/ui/stores/owners.js

@@ -3,7 +3,7 @@
  * the newest connected owner with an action of that name answers it, so an
  * owner that connects again replaces itself, and owners of different actions
  * sit side by side.
- * @returns {{connect: Function, detach: Function, act: Function}}
+ * @returns {{connect: Function, detach: Function, act: Function, owns: Function, ownerOf: Function}}
  */
 export function createOwners() {
   /** @type {Array<{actions: object}>} Oldest first. */
@@ -40,5 +40,25 @@ export function createOwners() {
     }
   }
 
-  return { connect, detach, act };
+  /**
+   * The token of the owner that answers `name`, if any.
+   * @param {string} name
+   * @returns {object | undefined}
+   */
+  function ownerOf(name) {
+    for (let index = owners.length - 1; index >= 0; index -= 1)
+      if (owners[index].actions[name]) return owners[index];
+  }
+
+  /**
+   * Whether the owner holding `token` is the one that answers `name`, so an
+   * owner that also publishes state can leave it to a newer one.
+   * @param {object} token
+   * @param {string} name
+   */
+  function owns(token, name) {
+    return Boolean(token) && ownerOf(name) === token;
+  }
+
+  return { connect, detach, act, owns, ownerOf };
 }

src/ui/stores/owners.test.mjs

@@ -33,3 +33,25 @@ test('act returns what the answering action returned', () => {
   assert.equal(act('pick', 'jazz'), 'kept jazz');
   assert.equal(act('missing'), undefined);
 });
+
+test('owns names the owner that answers an action', () => {
+  const { connect, detach, owns } = createOwners();
+  const older = connect({ tilt() {}, share() {} });
+  const newer = connect({ tilt() {} });
+  assert.equal(owns(newer, 'tilt'), true);
+  assert.equal(owns(older, 'tilt'), false);
+  assert.equal(owns(older, 'share'), true);
+  assert.equal(owns(newer, 'missing'), false);
+  assert.equal(owns(null, 'tilt'), false);
+  detach(newer);
+  assert.equal(owns(older, 'tilt'), true);
+});
+
+test('ownerOf names the token that answers an action', () => {
+  const { connect, ownerOf } = createOwners();
+  const older = connect({ clear() {}, share() {} });
+  const newer = connect({ clear() {} });
+  assert.equal(ownerOf('clear'), newer);
+  assert.equal(ownerOf('share'), older);
+  assert.equal(ownerOf('missing'), undefined);
+});

src/ui/views/panels/GlobeActions.vue

@@ -1,14 +1,19 @@
 <script setup>
 import { storeToRefs } from 'pinia';
+import { computed } from 'vue';
 import { t } from '../../../i18n/index.js';
 import { useGlobeActionsStore } from '../../stores/globeActions.js';
+import GlobeCompass from './GlobeCompass.vue';
 
-// The top-center camera and share actions. The shell answers the clear and
-// share buttons through the store and publishes a clear under way, which
-// keeps the button focusable and marks it busy.
+// The top-center camera and share actions. The shell answers the buttons
+// through the store and publishes a clear under way, which keeps the button
+// focusable and marks it busy, and the camera's tilt and heading. The heading
+// changes on every frame a rotating camera draws, so only the compass reads
+// it; the bar renders again only when the tilt changes.
 const globe = useGlobeActionsStore();
-const { clearBusy } = storeToRefs(globe);
+const { clearBusy, camera } = storeToRefs(globe);
 const { act } = globe;
+const tilted = computed(() => Boolean(camera.value?.tilted));
 </script>
 
 <template>
@@ -19,13 +24,10 @@ const { act } = globe;
   <button id="share-btn" type="button" aria-label="Copy share link" title="Copy share link" data-i18n-aria-label data-i18n-title @click="act('share')">
     <span class="share-icon" aria-hidden="true">&#x1F517;</span>
   </button>
-  <button id="tilt-map-view" type="button" aria-label="Tilt map to oblique view" aria-pressed="false" title="Toggle straight-down and tilted map views" data-i18n-aria-label data-i18n-title>
+  <button id="tilt-map-view" type="button" :aria-label="tilted ? t('Return map to straight-down view') : t('Tilt map to oblique view')" :aria-pressed="String(tilted)" title="Toggle straight-down and tilted map views" data-i18n-title @click="act('tilt')">
     <span class="material-symbols-outlined" aria-hidden="true">view_in_ar</span>
   </button>
-  <button id="north-up-view" type="button" aria-label="Reset map to north up" title="Reset map bearing to north" data-i18n-aria-label data-i18n-title>
-    <span class="camera-compass-n" aria-hidden="true">N</span>
-    <span class="camera-compass-needle material-symbols-outlined" aria-hidden="true">navigation</span>
-  </button>
+  <GlobeCompass @click="act('northUp')" />
   <button id="reset-globe-view" type="button" aria-label="Reset to full globe view" title="Reset camera and return to full globe view" data-i18n-aria-label data-i18n-title>
     <span class="material-symbols-outlined" aria-hidden="true">public</span>
   </button>

src/ui/views/panels/GlobeCompass.vue

@@ -0,0 +1,27 @@
+<script setup>
+import { storeToRefs } from 'pinia';
+import { computed } from 'vue';
+import { t } from '../../../i18n/index.js';
+import { useGlobeActionsStore } from '../../stores/globeActions.js';
+
+// The north-up button: its needle and label follow the published heading,
+// which changes on every frame a rotating camera draws. Before the camera
+// controls first publish, it shows no heading.
+defineEmits(['click']);
+const { camera } = storeToRefs(useGlobeActionsStore());
+const heading = computed(() => camera.value?.heading);
+const label = computed(() =>
+  heading.value == null
+    ? t('Reset map to north up')
+    : t('Reset map to north up. Current heading {heading} degrees', {
+        heading: heading.value,
+      }),
+);
+</script>
+
+<template>
+<button id="north-up-view" type="button" :aria-label="label" :data-north-up="heading == null ? undefined : String(heading === 0)" :style="heading == null ? undefined : { '--camera-heading': `${heading}deg` }" title="Reset map bearing to north" data-i18n-title @click="$emit('click')">
+  <span class="camera-compass-n" aria-hidden="true">N</span>
+  <span class="camera-compass-needle material-symbols-outlined" aria-hidden="true">navigation</span>
+</button>
+</template>