fix(street-level): KartaView review P2s; budget the gate's pick search

- Viewer: resizes while a sharper photo loads start no second load (the
  last size is looked at once it lands); decoded bitmaps nobody will draw
  (an overtaken preview or upgrade) are closed.
- Cones: a photo opened while the drive's first page loads is the one
  they centre on.
- A sequence page that lands while a lost WebGL context recovers keeps
  its cones: no pose is emitted without a renderer, and a viewer error
  never rejects page data.
- Source: an answer turned away unread (HTTP error, 429, length past the
  cap) aborts its request and cancels its body, freeing the connection.
- Gate: findPickPoint no longer picks each centre five times at radius 0,
  aims step 13's cone pick at the drawn billboards, and caps each
  evaluation at 4 s, resuming from a cursor on the next poll, so a slow
  machine cannot spend a whole wait in one evaluation.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

scripts/qa-street-level.mjs

@@ -507,6 +507,7 @@ async function assertKeylessKartaView(page) {
  * Runs in the page. Find a point where a real click picks `prefix` + `id` (any
  * id when null), searched around `points` ([lon, lat]), the aimed billboards,
  * or else a grid mid-screen. Only points where the canvas is topmost count.
+ * Each call picks for at most `budgetMs`; the next call resumes the search.
  * @returns {{x: number, y: number, id: string}|null} client coordinates
  */
 export function findPickPoint({
@@ -515,6 +516,7 @@ export function findPickPoint({
   points,
   billboardIds,
   billboardPrefix = null,
+  budgetMs = 4000,
 }) {
   const viewer = window.__godsEyeView.viewer;
   const scene = viewer.scene;
@@ -569,24 +571,54 @@ export function findPickPoint({
       centres.push([at.x, at.y]);
     }
   }
-  for (const [cx, cy] of centres)
-    for (let r = 0; r <= 16; r += 2)
+  // A pick is a render of the scene (0.5–2 s each under SwiftShader): try
+  // the centres the canvas is on top of first, nearest the screen centre,
+  // so the first pick usually hits.
+  const uncovered = ([x, y]) =>
+    document.elementFromPoint(rect.left + x, rect.top + y) === canvas;
+  const fromMiddle = ([x, y]) =>
+    (x - rect.width / 2) ** 2 + (y - rect.height / 2) ** 2;
+  centres.sort(
+    (a, b) =>
+      Number(uncovered(b)) - Number(uncovered(a)) ||
+      fromMiddle(a) - fromMiddle(b),
+  );
+  const candidates = [];
+  for (const [cx, cy] of centres) {
+    candidates.push([cx, cy]);
+    for (let r = 2; r <= 16; r += 2)
       for (const [dx, dy] of [
-        [0, 0],
         [r, 0],
         [-r, 0],
         [0, r],
         [0, -r],
-      ]) {
-        const hit = tryAt(cx + dx, cy + dy);
-        if (hit) return hit;
-      }
-  if (points || billboardIds) return null;
-  for (let y = rect.height * 0.25; y < rect.height * 0.8; y += 18)
-    for (let x = rect.width * 0.25; x < rect.width * 0.7; x += 6) {
-      const hit = tryAt(x, y);
-      if (hit) return hit;
+      ])
+        candidates.push([cx + dx, cy + dy]);
+  }
+  // Aimed at known places: never fall back to a scan of the whole screen.
+  if (!points && !billboardIds && billboardPrefix === null)
+    for (let y = rect.height * 0.25; y < rect.height * 0.8; y += 18)
+      for (let x = rect.width * 0.25; x < rect.width * 0.7; x += 6)
+        candidates.push([x, y]);
+  // One evaluation stays well inside the caller's wait: past the budget it
+  // returns null, and the next poll carries on from where this one stopped.
+  const key = JSON.stringify([prefix, id, billboardPrefix]);
+  const cursors = (window.__qaPickCursors ??= {});
+  const deadline = performance.now() + budgetMs;
+  let at = cursors[key] ?? 0;
+  if (at >= candidates.length) at = 0;
+  for (; at < candidates.length; at++) {
+    const hit = tryAt(...candidates[at]);
+    if (hit) {
+      delete cursors[key];
+      return hit;
     }
+    if (performance.now() > deadline) {
+      cursors[key] = at + 1;
+      return null;
+    }
+  }
+  delete cursors[key];
   return null;
 }
 
@@ -1542,22 +1574,28 @@ async function main() {
           );
           if (fixtures)
             assert.equal(sequence.images, fixture.images.length, 'every photo');
-          // The cones are on the globe: one of them picks as an image.
+          // The cones are on the globe: one of them picks as an image. Aim at
+          // where each cone billboard is drawn (its ground position at
+          // height 0 can sit a few pixels off, and every missed pick costs a
+          // render); the same 30 s as the line pick above.
           const cone = await page.waitForFunction(
             findPickPoint,
-            { timeout: 15_000, polling: 250 },
+            { timeout: 30_000, polling: 250 },
             {
               prefix: 'mly:img:',
               id: null,
-              points: fixtures
-                ? fixture.images.map((image) => [image.lon, image.lat])
-                : null,
+              points: null,
               billboardIds: null,
-              // Live: the cones' positions are only known from the globe.
-              billboardPrefix: fixtures ? null : 'mly:img:',
+              billboardPrefix: 'mly:img:',
             },
           );
-          assert.ok(await cone.jsonValue(), 'an image cone is pickable');
+          const picked = await cone.jsonValue();
+          assert.ok(picked, 'an image cone is pickable');
+          if (fixtures)
+            assert.ok(
+              fixture.images.some((image) => image.id === picked.id),
+              `the cone is a photo of the drive: ${picked.id}`,
+            );
           await page.evaluate(() =>
             window.__godsEyeView.dataManager.layers
               .get('street-level')
@@ -1685,7 +1723,9 @@ async function main() {
             assert.ok(neighbour, 'a neighbour of the other camera type');
             const handle = await page.waitForFunction(
               findPickPoint,
-              { timeout: 15_000, polling: 250 },
+              // A pick is a render; under SwiftShader on a busy machine one
+              // evaluation can take seconds.
+              { timeout: 30_000, polling: 250 },
               {
                 prefix: 'mly:img:',
                 id: neighbour.id,

src/layers/streetLevel/providers/kartaview/index.js

@@ -206,8 +206,13 @@ export function createKartaViewProvider({
                   ),
                 metresBetween,
               );
-              // The open photo may have just learnt which way it looked.
-              viewer.refreshPose?.();
+              // The open photo may have just learnt which way it looked. The
+              // page is good whatever the viewer is doing.
+              try {
+                viewer.refreshPose?.();
+              } catch {
+                /* the next pose carries the direction */
+              }
               return { page, hasMore, photos: list };
             });
           pages.set(key, entry);
@@ -362,10 +367,17 @@ export function createKartaViewProvider({
       const cones = createSequenceCones({
         state,
         async loadImages(sequenceId, { signal }) {
-          const anchor = anchors.get(sequenceId);
+          let anchor = anchors.get(sequenceId);
           if (!anchor) return [];
-          const window = await windowOf(anchor);
+          let window = await windowOf(anchor);
           signal?.throwIfAborted();
+          // Another photo of the drive opened while that page loaded (its
+          // re-centre found nothing drawn yet): centre on the newest one.
+          while (anchors.get(sequenceId) !== anchor) {
+            anchor = anchors.get(sequenceId);
+            window = await windowOf(anchor);
+            signal?.throwIfAborted();
+          }
           drawnPage = { sequenceId, page: window.home };
           countPhotos(sequenceId);
           return thinImages(

src/layers/streetLevel/providers/kartaview/provider.test.mjs

@@ -859,3 +859,104 @@ test('the marker is KartaView’s own cone, and it points along the drive, not a
     `then along the drive: ${bearings}`,
   );
 });
+
+/** Hold `seq`'s page `page` until the returned function is called. */
+function holdPage(source, seq, page) {
+  const getPage = source.getSequencePhotos;
+  let release;
+  const gate = new Promise((resolve) => (release = resolve));
+  source.getSequencePhotos = async (id, options) => {
+    if (id === seq && options.page === page) await gate;
+    return getPage(id, options);
+  };
+  return () => release();
+}
+
+test('a photo opened while the cones first load is the one they centre on', async (t) => {
+  const size = SEQUENCE_PAGE_SIZE;
+  const env = await mounted({
+    sequences: { s: Array.from({ length: size * 5 }, (_, i) => i) },
+  });
+  const cones = await withCones(t, env);
+  const release = holdPage(env.source, 's', 1);
+  await env.instance.viewer.open('s-10');
+  const selected = env.instance.selectSequence('s');
+  // A line click further along the drive while page 1 is still loading:
+  // nothing is drawn yet for its re-centre to move.
+  await env.instance.viewer.open(`s-${size * 4 + 10}`);
+  release();
+  await selected;
+  assert.ok(
+    await until(
+      () => !env.instance.sequenceStats().loading && cones.count() > 0,
+    ),
+  );
+  assert.ok(
+    cones()[0] <= size * 4 + 10 && cones()[1] >= size * 4 + 10,
+    `around the newer photo, not the first: ${cones()}`,
+  );
+});
+
+test('a sequence page that lands while a lost GPU context recovers still draws its cones', async (t) => {
+  const env = setup({ sequences: { p: [0, 1, 2, 3] } });
+  const sphere = (record) => ({
+    ...record,
+    projection: 'SPHERE',
+    fieldOfView: '360',
+    filepathProc: `2022/10/6/wrapped_proc/${record.id}.jpg`,
+  });
+  const getPhoto = env.source.getPhoto;
+  env.source.getPhoto = async (id) => sphere(await getPhoto(id));
+  const getPage = env.source.getSequencePhotos;
+  env.source.getSequencePhotos = async (...args) => {
+    const page = await getPage(...args);
+    return { ...page, photos: page.photos.map(sphere) };
+  };
+  const release = holdPage(env.source, 'p', 1);
+  let holdImages = false;
+  let releaseImage = null;
+  const view = { yaw: 0, pitch: 0, fov: 80 };
+  const definition = createKartaViewProvider({
+    source: env.source,
+    viewerOptions: {
+      load: async (url) => {
+        if (holdImages) await new Promise((r) => (releaseImage = r));
+        return { src: url };
+      },
+      createRenderer: () => ({
+        setImage() {},
+        setView: (next) => Object.assign(view, next),
+        getView: () => ({ ...view }),
+        resize() {},
+        clear() {},
+        destroy() {},
+      }),
+    },
+  });
+  const { context, actions } = fakeContext();
+  const errors = [];
+  context.actions.reportError = (message) => errors.push(message);
+  const instance = definition.create(context);
+  actions.instance = instance;
+  const cones = await withCones(t, { instance });
+  const host = fakeHost();
+  await instance.viewer.mount(host);
+  await instance.viewer.open('p-0');
+  // › to the next panorama; the GPU resets while it loads.
+  holdImages = true;
+  const opening = instance.viewer.open('p-1');
+  assert.ok(await until(() => releaseImage !== null));
+  host.children[0].children[1].fire('webglcontextlost');
+  const selected = instance.selectSequence('p');
+  release();
+  await selected;
+  assert.ok(
+    await until(() => !instance.sequenceStats().loading && cones.count() > 0),
+    'the page is drawn, not dropped',
+  );
+  releaseImage();
+  await opening;
+  assert.equal(host.children[0].dataset.kind, 'pano', 'p-1 shows');
+  // reportError(null) clears; nothing was reported.
+  assert.deepEqual(errors.filter(Boolean), []);
+});

src/layers/streetLevel/providers/kartaview/source.js

@@ -145,8 +145,10 @@ export function createKartaViewSource({
         ),
       timeoutMs,
     );
+    let response = null;
+    let read = false;
     try {
-      const response = await fetchImpl(url, { signal: controller.signal });
+      response = await fetchImpl(url, { signal: controller.signal });
       if (response.status === 429)
         throw new KartaViewSourceError('KartaView is rate-limiting requests', {
           status: 429,
@@ -166,6 +168,7 @@ export function createKartaViewSource({
       // KartaView answers chunked, without a length: count while reading.
       const reader = response.body?.getReader?.();
       if (!reader) {
+        read = true;
         try {
           return await response.json();
         } catch (error) {
@@ -175,6 +178,7 @@ export function createKartaViewSource({
           });
         }
       }
+      read = true;
       const chunks = [];
       let bytes = 0;
       for (;;) {
@@ -209,6 +213,13 @@ export function createKartaViewSource({
     } finally {
       clearTimeout(timer);
       signal?.removeEventListener('abort', onAbort);
+      // An answer turned away unread (429, an error, too long) still holds
+      // its connection, one of the six the browser has: let it go.
+      if (response && !read) {
+        controller.abort();
+        if (response.body && !response.body.locked)
+          response.body.cancel?.().catch?.(() => {});
+      }
     }
   }
 

src/layers/streetLevel/providers/kartaview/source.test.mjs

@@ -595,3 +595,62 @@ test('a sequence page gets the full 30 s on its first try, then 30 s once more',
   assert.match(String(outcome?.error?.message), /did not answer in time/);
   assert.equal(outcome.at, 2 * PAGE_TIMEOUT_MS);
 });
+
+test('an answer turned away unread (an error, a 429, a length past the cap) lets its connection go', async () => {
+  /** A response whose body is never read: records its cancel and the abort. */
+  const unread = (answer) => {
+    const seen = { cancelled: false, signal: null };
+    const fetchImpl = async (url, { signal }) => {
+      seen.signal = signal;
+      return {
+        ...answer,
+        body: {
+          locked: false,
+          getReader: () => {
+            throw new Error('not read');
+          },
+          cancel: async () => {
+            seen.cancelled = true;
+          },
+        },
+      };
+    };
+    return { seen, fetchImpl };
+  };
+  const cases = [
+    [{ ok: false, status: 503, headers: new Map() }, /HTTP 503/],
+    [
+      {
+        ok: true,
+        status: 200,
+        headers: new Map([['content-length', String(64 * 1024 * 1024)]]),
+      },
+      /too much data/,
+    ],
+  ];
+  for (const [answer, message] of cases) {
+    const { seen, fetchImpl } = unread(answer);
+    const source = createKartaViewSource({ fetchImpl });
+    await assert.rejects(source.getTile({ x: 1, y: 2, z: 13 }), message);
+    assert.equal(seen.signal.aborted, true, `${message}: request aborted`);
+    assert.equal(seen.cancelled, true, `${message}: body cancelled`);
+  }
+  // A 429 is let go before its retry is asked.
+  const { seen, fetchImpl } = unread({
+    ok: false,
+    status: 429,
+    headers: new Map([['retry-after', '0']]),
+  });
+  const signals = [];
+  const source = createKartaViewSource({
+    fetchImpl: async (url, init) => {
+      signals.push(init.signal);
+      if (signals.length === 1) return fetchImpl(url, init);
+      return ok(photoPayload([]));
+    },
+  });
+  await source.getPhoto('1');
+  assert.equal(signals[0].aborted, true);
+  assert.equal(seen.cancelled, true);
+  assert.equal(signals[1].aborted, false, 'a read answer is left alone');
+});

src/layers/streetLevel/providers/kartaview/viewer.js

@@ -73,6 +73,11 @@ async function loadBitmap(url, timeoutMs) {
   }
 }
 
+/** Free a decoded bitmap nobody will draw (an <img> has nothing to free). */
+function release(image) {
+  image?.close?.();
+}
+
 /** The panorama size a canvas this wide can show sharply at this field of view. */
 export function panoSizeFor(canvasPixels, fovDeg) {
   const needed = (Math.max(1, canvasPixels) * 360) / Math.max(1, fovDeg);
@@ -130,6 +135,10 @@ export function createKartaViewViewer({
   let panoWidth = 0;
   /** The flat photo on screen is the 2,560 px version. */
   let flatSharp = false;
+  /** The sharper version loading ({seq, kind}): a resize starts no second one. */
+  let upgrading = null;
+  /** A resize came while it loaded: look again once it lands. */
+  let upgradeAgain = false;
   /** The photo an open is fetching: ‹ › step on from it, not the old one. */
   let openingId = null;
   /** ‹ › chose this photo: keep the panorama's look direction for it. */
@@ -143,6 +152,9 @@ export function createKartaViewViewer({
 
   function emit() {
     if (!photo || !showing) return;
+    // A lost GPU context, still being recovered: the open that redraws the
+    // panorama poses once it is on screen.
+    if (showing === 'pano' && !renderer) return;
     const view = showing === 'pano' ? renderer.getView() : null;
     const heading = cameraBearing(photo);
     const pose = {
@@ -485,20 +497,40 @@ export function createKartaViewViewer({
         ? resizedImageUrl(target.urls.pano, size)
         : resizedImageUrl(target.urls.full, size);
     if (!url) return;
+    // Resizes come in bursts while the panel animates: one load at a time
+    // for this photo, and one more look once it lands.
+    if (upgrading?.seq === seq && upgrading.kind === kind) {
+      upgradeAgain = true;
+      return;
+    }
+    const pending = (upgrading = { seq, kind });
+    upgradeAgain = false;
+    let image = null;
     try {
-      const image = await load(url, { crossOrigin: kind === 'pano' });
+      image = await load(url, { crossOrigin: kind === 'pano' });
       if (seq !== openSeq || photo !== target || showing !== kind) return;
       if (kind === 'pano') {
         if (!renderer || size[0] <= panoWidth) return;
         renderer.setImage(image);
+        image = null;
         panoWidth = size[0];
       } else {
         picture.src = image.src;
+        image = null;
         flatSharp = true;
       }
       requestRender();
     } catch {
       /* the first version stays */
+    } finally {
+      release(image);
+      if (upgrading === pending) {
+        upgrading = null;
+        if (upgradeAgain && seq === openSeq && photo === target) {
+          upgradeAgain = false;
+          upgrade(target, seq, showing);
+        }
+      }
     }
   }
 
@@ -524,10 +556,16 @@ export function createKartaViewViewer({
       resizedImageUrl(target.urls.pano, PANO_PREVIEW_SIZE),
       { crossOrigin: true },
     );
-    if (seq !== openSeq) return false;
+    if (seq !== openSeq) {
+      release(image);
+      return false;
+    }
     // The context may have been lost while this loaded: build on the new
     // canvas, or let the caller show the front view.
-    if (!ensureRenderer()) throw new Error(LOAD_FAILED);
+    if (!ensureRenderer()) {
+      release(image);
+      throw new Error(LOAD_FAILED);
+    }
     const restore = restoreView?.id === target.id ? restoreView.view : null;
     restoreView = null;
     if (restore) renderer.setView(restore);

src/layers/streetLevel/providers/kartaview/viewer.test.mjs

@@ -105,8 +105,11 @@ function setup({
   rendererThrows = false,
   steps = {},
   failSteps = false,
+  hold = () => false,
 } = {}) {
   const loads = [];
+  const held = [];
+  const closed = [];
   const renderers = [];
   const stepped = [];
   const asked = [];
@@ -130,7 +133,10 @@ function setup({
       loads.push({ url, crossOrigin: options?.crossOrigin });
       if (failLoads.some((part) => url.includes(part)))
         throw new Error('The KartaView photo could not be loaded');
-      return { src: url };
+      // A decoded bitmap: close() frees it.
+      const image = { src: url, close: () => closed.push(url) };
+      if (!hold(url)) return image;
+      return new Promise((resolve) => held.push(() => resolve(image)));
     },
     createRenderer: (canvas) => {
       attempts.renderer++;
@@ -152,6 +158,8 @@ function setup({
     stepped,
     asked,
     attempts,
+    held,
+    closed,
   };
 }
 
@@ -923,3 +931,54 @@ test('a docked viewer keeps the 1,280 px photo; expanding it brings the 2,560 px
   for (let i = 0; i < 4; i++) await settle();
   assert.equal(loads.length, 2, 'once only');
 });
+
+test('resizes while a sharper panorama loads start no second load; the last size wins once it lands', async () => {
+  let first = true;
+  const { viewer, host, loads, renderers, held } = setup({
+    hold: (url) => {
+      const holdIt = first && url.includes('rs:fit:2048');
+      if (holdIt) first = false;
+      return holdIt;
+    },
+  });
+  await viewer.mount(host);
+  await viewer.open('pano1');
+  assert.ok(await until(() => held.length === 1));
+  // The panel animates open: a burst of resizes while 2,048 px loads.
+  parts(host).canvas.clientWidth = 1400;
+  for (let i = 0; i < 5; i++) viewer.resize();
+  for (let i = 0; i < 4; i++) await settle();
+  assert.equal(loads.length, 2, 'the preview and the one 2,048 px load');
+  held[0]();
+  assert.ok(await until(() => renderers[0].images.length === 3));
+  assert.match(renderers[0].images[1], /rs:fit:2048:1024/);
+  assert.match(renderers[0].images[2], /rs:fit:4096:2048/);
+  for (let i = 0; i < 4; i++) await settle();
+  assert.equal(loads.length, 3, 'one more load, for the size asked last');
+});
+
+test('a preview or sharper version nobody will draw is freed, not left decoded', async () => {
+  const { viewer, host, renderers, held, closed } = setup({
+    hold: (url) => /rs:fit:(1024|2048):/.test(url),
+  });
+  await viewer.mount(host);
+  // pano1's preview is still loading when flat1 opens over it.
+  const overtaken = viewer.open('pano1');
+  assert.ok(await until(() => held.length === 1));
+  await viewer.open('flat1');
+  held[0]();
+  await overtaken;
+  assert.deepEqual(closed.length, 1);
+  assert.match(closed[0], /rs:fit:1024/, 'the overtaken preview');
+  // pano1 shows; its sharp version lands after flat1 replaced it.
+  const shown = viewer.open('pano1');
+  assert.ok(await until(() => held.length === 2));
+  held[1]();
+  await shown;
+  assert.ok(await until(() => held.length === 3));
+  await viewer.open('flat1');
+  held[2]();
+  assert.ok(await until(() => closed.length === 2));
+  assert.match(closed[1], /rs:fit:2048/, 'the overtaken sharp version');
+  assert.equal(renderers[0].images.length, 1, 'only the preview was drawn');
+});