fix(m4): keep tape calibration on one page (#99)

frontend/src/App.svelte

@@ -26,7 +26,6 @@
 
   let cap: Capture = { k: 'batch', photos: [] };
   let busy = false;
-  let pngUrl: string | null = null;
   let showSettings = false;
   let showSlabs = false;
 
@@ -37,7 +36,6 @@
 
   const unsubCap = session.capture.subscribe((c) => {
     cap = c;
-    pngUrl = c.k === 'measure' ? session.getInventoryUrl() : null;
   });
   const unsubBusy = session.busy.subscribe((b) => (busy = b));
 
@@ -228,17 +226,13 @@
             session.setCropFill(pct);
             void updateSettings({ crop_fill: pct }).catch(() => {});
           }}
-          approveAxis={session.approveAxis}
+          calculateFromAxis={session.calculateFromAxis}
           back={session.back}
         />
-      {:else}
+      {:else if cap.k === 'measure'}
         <MeasurePanel
           state={cap}
-          setLength={session.setLength}
-          setThickness={session.setThickness}
-          calculate={session.calculate}
           back={session.back}
-          {pngUrl}
           onContinue={saving ? undefined : () => void continueToReview()}
         />
       {/if}

frontend/src/capture/AxisPanel.svelte

@@ -1,6 +1,7 @@
 <script lang="ts">
   import { onDestroy, onMount } from 'svelte';
   import type { Capture, PhotoTransform } from './capture.types';
+  import { eighthsToIn, inToEighths } from './capture.types';
   import { decodeOrientedBitmap } from '../decodeOrientedBitmap';
   import {
     CALIBRATION_FRAME,
@@ -20,7 +21,7 @@
     sourceH: number;
   }) => void;
   export let setCropFill: (pct: number) => void = () => {};
-  export let approveAxis: () => void;
+  export let calculateFromAxis: (lengthEighths: number, thicknessEighths: number) => Promise<void>;
   export let back: () => void;
 
   const frame = CALIBRATION_FRAME;
@@ -36,6 +37,9 @@
   let tickB = state.axis.tickEndY;
   let focus: 'A' | 'B' = 'A';
   let fill = cropFill;
+  let lengthIn = state.lengthEighths === 0 ? '' : String(eighthsToIn(state.lengthEighths));
+  let thicknessIn = state.thicknessEighths === 0 ? '' : String(eighthsToIn(state.thicknessEighths));
+  let calcBusy = false;
   let drag: 'tick' | 'tilt' | 'pan' | 'pinch' | null = null;
   let pointers = new Map<number, [number, number]>();
   let pinch0 = 0;
@@ -266,6 +270,31 @@
     reseat(fill);
   }
 
+  const positiveInches = (raw: string): number | null => {
+    const inches = Number.parseFloat(raw);
+    return Number.isFinite(inches) && inches > 0 ? inches : null;
+  };
+
+  const commitInches = (raw: string): number => {
+    const inches = positiveInches(raw);
+    return inches === null ? 0 : inToEighths(inches);
+  };
+
+  async function onCalculate() {
+    const length = commitInches(String(lengthIn));
+    const thickness = commitInches(String(thicknessIn));
+    lengthIn = length === 0 ? '' : String(eighthsToIn(length));
+    thicknessIn = thickness === 0 ? '' : String(eighthsToIn(thickness));
+    if (length === 0 || thickness === 0) return;
+    calcBusy = true;
+    try {
+      publish();
+      await calculateFromAxis(length, thickness);
+    } finally {
+      calcBusy = false;
+    }
+  }
+
   onMount(async () => {
     const bmp = await decodeOrientedBitmap(state.source.blob);
     bitmap = bmp;
@@ -332,9 +361,22 @@
     <span class="val">{fill}%</span>
   </div>
 
+  <div class="fields">
+    <label class="field">
+      <span class="ctl">Length L (tape reading)</span>
+      <input type="number" aria-label="Length L" inputmode="decimal" step="0.125" min="0" placeholder="0" bind:value={lengthIn} />
+    </label>
+    <label class="field">
+      <span class="ctl">Thickness</span>
+      <input type="number" aria-label="Thickness" inputmode="decimal" step="0.125" min="0" placeholder="0" bind:value={thicknessIn} />
+    </label>
+  </div>
+
   <div class="actions">
     <button type="button" class="ghost" on:click={back}>Back</button>
-    <button type="button" class="primary" on:click={approveAxis}>Approve tape line</button>
+    <button type="button" class="primary" disabled={calcBusy || positiveInches(String(lengthIn)) === null || positiveInches(String(thicknessIn)) === null} on:click={onCalculate}>
+      {calcBusy ? 'Calculating…' : 'Calculate'}
+    </button>
   </div>
 </section>
 
@@ -354,6 +396,13 @@
   .val { min-width: 5ch; text-align: right; font-variant-numeric: tabular-nums; }
   .fit { margin-top: 8px; }
   .actions { display: flex; gap: 10px; margin-top: 16px; }
+  .fields { display: flex; gap: 12px; margin-top: 8px; }
+  .field { flex: 1; }
+  .field input {
+    box-sizing: border-box; width: 100%; min-height: 44px; padding: 10px; font-size: 1rem;
+    border-radius: 3px; border: 1px solid #444; background: #1d1d1d; color: #eee;
+  }
+  .primary:disabled { background: #333; color: #777; }
   .primary {
     flex: 2; padding: 12px; font-size: 1rem; border-radius: 3px; border: 0;
     background: #00e5ff; color: #002; font-weight: 700;

frontend/src/capture/MeasurePanel.svelte

@@ -1,9 +1,7 @@
 <script lang="ts">
   import { onDestroy } from 'svelte';
   import type { Capture } from './capture.types';
-  import { inToEighths, eighthsToIn } from './capture.types';
   import { fmtEighths } from './session';
-  import PhotoStage from './PhotoStage.svelte';
   import {
     buildPhotosReadyLineup,
     photosReadyPngAlt,
@@ -11,22 +9,13 @@
   } from './photosReadyLineup';
 
   export let state: Extract<Capture, { k: 'measure' }>;
-  export let setLength: (e: number) => void;
-  export let setThickness: (e: number) => void;
-  export let calculate: () => Promise<void>;
   export let back: () => void;
-  export let pngUrl: string | null;
   /** C2: hand off the calibrated capture to Review (App builds the slab + uploads). */
   export let onContinue: (() => void) | undefined = undefined;
 
-  let calcBusy = false;
-  let lengthIn = state.lengthEighths === 0 ? '' : String(eighthsToIn(state.lengthEighths));
-  let thicknessIn = state.thicknessEighths === 0 ? '' : String(eighthsToIn(state.thicknessEighths));
-
   let lineupUrls: string[] = [];
   let lineupItems: PhotosReadyLineupItem[] = [];
 
-  $: photosReady = !!state.results;
   $: {
     for (const u of lineupUrls) URL.revokeObjectURL(u);
     lineupUrls = [];
@@ -48,92 +37,17 @@
   onDestroy(() => {
     for (const u of lineupUrls) URL.revokeObjectURL(u);
   });
-
-  const positiveInches = (raw: string): number | null => {
-    const inches = Number.parseFloat(raw);
-    return Number.isFinite(inches) && inches > 0 ? inches : null;
-  };
-
-  const commitLength = () => {
-    const inches = positiveInches(String(lengthIn));
-    const eighths = inches === null ? 0 : inToEighths(inches);
-    setLength(eighths);
-    lengthIn = eighths === 0 ? '' : String(eighthsToIn(eighths));
-  };
-  const commitThickness = () => {
-    const inches = positiveInches(String(thicknessIn));
-    const eighths = inches === null ? 0 : inToEighths(inches);
-    setThickness(eighths);
-    thicknessIn = eighths === 0 ? '' : String(eighthsToIn(eighths));
-  };
-
-  $: canCalc = positiveInches(String(lengthIn)) !== null && positiveInches(String(thicknessIn)) !== null;
-
-  const doCalc = async () => {
-    calcBusy = true;
-    try {
-      commitLength();
-      commitThickness();
-      await calculate();
-    } finally { calcBusy = false; }
-  };
 </script>
 
 <section class="panel">
-  <h1>{photosReady ? 'Photos ready' : 'Measure'}</h1>
+  <h1>Photos ready</h1>
-
-  {#if !photosReady}
-    <PhotoStage
-      blob={state.source.blob}
-      bbox={state.axis.bbox}
-      maskBitset={state.approvedMask.bitset}
-      maskW={state.source.widthPx > 0 ? state.source.widthPx : 0}
-      maskH={state.source.widthPx > 0 ? state.approvedMask.bitset.length / state.source.widthPx : 0}
-    />
-
-    <div class="fields">
-      <div class="field">
-        <span class="label">Length L (tape reading)</span>
-        <input
-          type="number"
-          aria-label="Length L"
-          inputmode="decimal"
-          step="0.125"
-          min="0"
-          placeholder="0"
-          bind:value={lengthIn}
-          on:blur={commitLength}
-          on:change={commitLength}
-        />
-      </div>
-      <div class="field">
-        <span class="label">Thickness</span>
-        <input
-          type="number"
-          aria-label="Thickness"
-          inputmode="decimal"
-          step="0.125"
-          min="0"
-          placeholder="0"
-          bind:value={thicknessIn}
-          on:blur={commitThickness}
-          on:change={commitThickness}
-        />
-      </div>
-    </div>
 
+  {#if !state.results}
+    <p class="hint">Calculating…</p>
     <div class="row">
       <button type="button" class="ghost" on:click={back}>Back</button>
-      <button
-        type="button"
-        class="primary"
-        disabled={calcBusy || !canCalc}
-        on:click={doCalc}
-      >
-        {calcBusy ? 'Calculating…' : 'Calculate'}
-      </button>
     </div>
-  {:else if state.results}
+  {:else}
     <div class="results" aria-label="Photos ready">
       <div class="nums">
         <div><span>Widths</span><span>{fmtEighths(state.results.widths.min)} – {fmtEighths(state.results.widths.max)} (avg {fmtEighths(state.results.widths.avg)})</span></div>
@@ -169,12 +83,6 @@
         {/each}
       </ol>
 
-      <!-- Legacy single-PNG fallback only when lineup helper yielded nothing but pngUrl exists -->
-      {#if lineupItems.length === 0 && pngUrl && !state.results.sourceBelowFloor}
-        <div class="png-wrap">
-          <img src={pngUrl} alt="Inventory PNG" />
-        </div>
-      {/if}
     </div>
 
     <div class="row">
@@ -191,14 +99,6 @@
 <style>
   .panel { padding: 16px; color: #eee; }
   h1 { font-size: 1.3rem; margin: 0 0 12px; }
-  .fields { display: flex; gap: 16px; margin-top: 16px; }
-  .field { flex: 1; }
-  .label { display: block; font-size: 0.9rem; color: #aaa; margin-bottom: 8px; }
-  .field input {
-    box-sizing: border-box; width: 100%; min-height: 52px; padding: 12px; font-size: 1rem;
-    border-radius: 10px; border: 1px solid #444; background: #1d1d1d; color: #eee;
-    font-variant-numeric: tabular-nums;
-  }
   .row { display: flex; gap: 10px; margin-top: 20px; }
   .primary {
     flex: 2; padding: 14px; font-size: 1.05rem; border-radius: 10px; border: 0;
@@ -229,6 +129,4 @@
   }
   .err-title { color: #ffb4a2; font-weight: 700; font-size: 0.95rem; }
   .err-msg { color: #e8cfc8; font-size: 0.9rem; }
-  .png-wrap { margin-top: 16px; text-align: center; background-image: linear-gradient(45deg,#ccc 25%,transparent 25%),linear-gradient(-45deg,#ccc 25%,transparent 25%),linear-gradient(45deg,transparent 75%,#ccc 75%),linear-gradient(-45deg,transparent 75%,#ccc 75%); background-size: 16px 16px; background-position: 0 0,0 8px,8px -8px,-8px 0; background-color: #eee; border-radius: 8px; padding: 8px; }
-  .png-wrap img { max-width: 100%; border-radius: 4px; }
 </style>

frontend/src/capture/capture.types.ts

@@ -108,7 +108,9 @@ export type Capture =
       k: 'axis';
       source: Source;
       approvedMask: Mask; // frozen footprint
-      axis: Axis; // live axis.bbox being nudged
+      axis: Axis; // live tape line
+      lengthEighths: Eighths;
+      thicknessEighths: Eighths;
     }
   | {
       k: 'measure';

frontend/src/capture/measureInputs.test.ts

@@ -6,11 +6,15 @@ import { test } from 'node:test';
 import { inToEighths } from './capture.types';
 
 const panelSrc = readFileSync(
+  join(dirname(fileURLToPath(import.meta.url)), 'AxisPanel.svelte'),
+  'utf8',
+);
+const measureSrc = readFileSync(
   join(dirname(fileURLToPath(import.meta.url)), 'MeasurePanel.svelte'),
   'utf8',
 );
 
-test('MeasurePanel exposes typed number inputs for Length L and Thickness', () => {
+test('tape page exposes typed number inputs for Length L and Thickness', () => {
   const inputs = panelSrc.match(/<input\b[^>]*>/g) ?? [];
   assert.ok(inputs.length >= 2, 'expected at least two <input> fields');
   assert.ok(
@@ -31,6 +35,11 @@ test('MeasurePanel exposes typed number inputs for Length L and Thickness', () =
     false,
     'Length must not be a read-only fmtEighths span',
   );
+  assert.equal(
+    /aria-label="Length L"/.test(measureSrc),
+    false,
+    'the separate measure page must not collect length',
+  );
 });
 
 test('typed inches snap to nearest 1/8 via inToEighths', () => {

frontend/src/capture/session.calibrate.test.ts

@@ -358,6 +358,51 @@ test('#61: after pick of index N≠0, Mask/Axis/Measure operate on that blob onl
   s.dispose();
 });
 
+test('calculateFromAxis stays on the tape page until the calibrated result exists', async () => {
+  installFakeMaskWorker();
+  (globalThis as unknown as { createImageBitmap: typeof createImageBitmap }).createImageBitmap =
+    async () => ({ width: MASK_W, height: MASK_H, close() {} }) as ImageBitmap;
+
+  let releaseCalibration!: () => void;
+  const calibrationGate = new Promise<void>((resolve) => { releaseCalibration = resolve; });
+  const s = createCaptureSession({
+    draft: store,
+    encodeInventory: async () => {
+      await calibrationGate;
+      return { blob: new Blob(['clean'], { type: 'image/png' }), sourceBelowFloor: false };
+    },
+    encodeOverlay: async () => new Blob(['overlay'], { type: 'image/png' }),
+  });
+  const a = tinyJpeg('a');
+  await s.addToBatch(a);
+  s.continueBatch();
+  s.pickCalibration(0);
+  s.setSheet('black');
+  await settleOverlay(s);
+  s.approveMask();
+  assert.equal(get(s.capture).k, 'axis');
+
+  const calculating = s.calculateFromAxis(320, 16);
+  await new Promise((r) => setTimeout(r, 0));
+  const during = get(s.capture);
+  assert.equal(during.k, 'axis', 'tape page stays mounted while Calculate runs');
+  if (during.k === 'axis') {
+    assert.equal(during.lengthEighths, 320);
+    assert.equal(during.thicknessEighths, 16);
+  }
+
+  releaseCalibration();
+  await calculating;
+  const after = get(s.capture);
+  assert.equal(after.k, 'measure');
+  if (after.k === 'measure') {
+    assert.ok(after.results, 'Photos ready opens only with a completed result');
+    assert.equal(after.lengthEighths, 320);
+    assert.equal(after.thicknessEighths, 16);
+  }
+  s.dispose();
+});
+
 test('#61: Calculate produces inventory PNG + M1 measures for calibration source only', async () => {
   installFakeMaskWorker();
   (globalThis as unknown as { createImageBitmap: typeof createImageBitmap }).createImageBitmap =
@@ -520,6 +565,53 @@ test('#61: draft resume through measure restores calibration source (not photos[
   s2.dispose();
 });
 
+test('legacy measure draft without results returns to the tape calibration page', async () => {
+  installFakeMaskWorker();
+  const source = tinyJpeg('legacy');
+  store.saveDraft({
+    version: 1,
+    stage: 'measure',
+    batch: [source],
+    calibrationIndex: 0,
+    source,
+    maskParams: { sheet: 'black', sensitivity: 50 },
+    mask: {
+      slabPx: MASK_W * MASK_H,
+      bbox: {
+        corners: [[MASK_W, 0], [MASK_W, MASK_H], [0, MASK_H], [0, 0]],
+        longSidePx: MASK_W,
+        angleDeg: 0,
+      },
+      slabBounds: { x: 0, y: 0, w: MASK_W, h: MASK_H },
+    },
+    axisBbox: {
+      corners: [[MASK_W, 0], [MASK_W, MASK_H], [0, MASK_H], [0, 0]],
+      longSidePx: MASK_W,
+      angleDeg: 0,
+    },
+    lengthEighths: 320,
+    thicknessEighths: 16,
+    results: null,
+    inventoryPng: null,
+  });
+
+  const s = createCaptureSession({ draft: store });
+  await s.resumeProbe();
+  s.continueDraft();
+  const start = Date.now();
+  let cap = get(s.capture);
+  while (cap.k !== 'axis' && Date.now() - start < 1500) {
+    await new Promise((r) => setTimeout(r, 10));
+    cap = get(s.capture);
+  }
+  assert.equal(cap.k, 'axis', 'legacy resultless measure draft must not open a dead result screen');
+  if (cap.k === 'axis') {
+    assert.equal(cap.lengthEighths, 320);
+    assert.equal(cap.thicknessEighths, 16);
+  }
+  s.dispose();
+});
+
 test('#61: App runs single Mask/Axis/Measure panels (no per-batch Mask loop)', () => {
   const app = readFileSync(join(here, '..', 'App.svelte'), 'utf8');
   assert.match(app, /MaskPanel/);

frontend/src/capture/session.ts

@@ -48,12 +48,14 @@ export interface CaptureSession {
     sourceH: number;
   }): void;
   setCropFill(pct: number): void;
+  /** Legacy resultless transition retained for old callers/tests; the shipped UI uses calculateFromAxis. */
   approveAxis(): void;
+  /** Length and thickness are entered on the tape page. Calculate leaves that page for Photos ready. */
+  calculateFromAxis(lengthEighths: Eighths, thicknessEighths: Eighths): Promise<void>;
   setLength(e: Eighths): void;
   setThickness(e: Eighths): void;
   calculate(): Promise<void>;
   back(): void;
-  getInventoryUrl(): string | null;
   /** The current `measure` branch, or null while not on it (C2 handoff). */
   currentMeasure(): Extract<Capture, { k: 'measure' }> | null;
   dispose(): void;
@@ -72,6 +74,19 @@ const defaultDraft: DraftStore = { loadDraft, saveDraft, clearDraft };
 const batchPhotosOf = (d: Draft): Source[] =>
   d.batch && d.batch.length > 0 ? d.batch : [d.source];
 
+type CalibrationInput = {
+  source: Source;
+  approvedMask: Mask;
+  axis: Axis;
+  lengthEighths: Eighths;
+  thicknessEighths: Eighths;
+};
+
+type CalibrationOutput = {
+  results: Measures;
+  batchApply: BatchPhotoResult[];
+};
+
 // The one writer. Owns the worker port, the single debounce timer, and the draft.
 // Every transition to an approved branch persists; no explicit "save".
 export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
@@ -88,7 +103,6 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
   let timer: ReturnType<typeof setTimeout> | null = null;
   let passStarted = 0;
   let busyTimer: ReturnType<typeof setTimeout> | null = null;
-  let pngUrl: string | null = null;
   let resumed = false;
   let cropFill = 90;
   let poseTimer: ReturnType<typeof setTimeout> | null = null;
@@ -130,10 +144,6 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
       }
       worker = null;
     }
-    if (pngUrl) {
-      URL.revokeObjectURL(pngUrl);
-      pngUrl = null;
-    }
   };
 
   const makeWorker = (blob: Blob) => {
@@ -239,7 +249,7 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
         tickEndY: state.axis.tickEndY,
         tapeStart: state.axis.tapeStart,
         tapeEnd: state.axis.tapeEnd,
-        lengthEighths: 0, thicknessEighths: 0, results: null, inventoryPng: null,
+        lengthEighths: state.lengthEighths, thicknessEighths: state.thicknessEighths, results: null, inventoryPng: null,
       };
     }
     if (state.k === 'measure') {
@@ -345,6 +355,91 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
     stub: Omit<Mask, 'bitset' | 'params'>,
   ): Promise<Mask> => rederiveMaskDetailed(source, params, stub).then((r) => r.mask);
 
+  const runCalibration = async (input: CalibrationInput): Promise<CalibrationOutput> => {
+    const { source, approvedMask, axis, lengthEighths, thicknessEighths } = input;
+    if (lengthEighths === 0 || thicknessEighths === 0) {
+      throw new Error('length and thickness are required');
+    }
+    const bitmap = await decodeOrientedBitmap(source.blob);
+    let pngBlob: Blob;
+    let belowFloor = false;
+    try {
+      const base = measure(
+        approvedMask.bitset, source.widthPx, source.heightPx,
+        axis.bbox, lengthEighths, thicknessEighths, approvedMask.slabPx,
+        { start: axis.tapeStart, end: axis.tapeEnd },
+      );
+      try {
+        const encoded = await encodeInventory({ bitmap, mask: approvedMask, source, cropFill });
+        pngBlob = encoded.blob;
+        belowFloor = encoded.sourceBelowFloor;
+      } catch {
+        pngBlob = new Blob([], { type: 'image/png' });
+      }
+      const overlayBlob = await (async () => {
+        try {
+          return await encodeOverlay({
+            inventoryPng: pngBlob,
+            bitset: approvedMask.bitset,
+            widthPx: source.widthPx,
+            heightPx: source.heightPx,
+            bbox: axis.bbox,
+            scale: base.scale,
+            lengthIn: eighthsToIn(lengthEighths),
+            lengthLabel: fmtEighths(lengthEighths),
+            slabBounds: approvedMask.slabBounds,
+            source,
+            cropFill,
+          });
+        } catch {
+          return new Blob(['overlay'], { type: 'image/png' });
+        }
+      })();
+      const results: Measures = {
+        ...base,
+        inventoryPng: pngBlob,
+        overlayPng: overlayBlob,
+        sourceBelowFloor: belowFloor,
+      };
+      const calIndex = calibrationIndex != null && calibrationIndex >= 0
+        ? calibrationIndex
+        : 0;
+      const batch = batchPhotos.length ? batchPhotos : [source];
+      const batchApply: BatchPhotoResult[] = batch.map((_, index) => (index === calIndex ? null : {
+        status: 'error',
+        message: 'Batch photo was not processed',
+      }));
+      for (let index = 0; index < batch.length; index++) {
+        if (index === calIndex) continue;
+        const photo = batch[index];
+        try {
+          const derived = await rederiveMaskDetailed(photo, approvedMask.params, {
+            slabPx: 0,
+            bbox: EMPTY_BBOX,
+            slabBounds: EMPTY_ABOX,
+          });
+          if (derived.mask.slabPx === 0) throw new Error('empty mask: no slab pixels detected');
+          const siblingSource: Source = { ...photo, widthPx: derived.widthPx, heightPx: derived.heightPx };
+          const siblingBitmap = await decodeOrientedBitmap(photo.blob);
+          let encoded: { blob: Blob; sourceBelowFloor: boolean };
+          try {
+            encoded = await encodeInventory({ bitmap: siblingBitmap, mask: derived.mask, source: siblingSource, cropFill });
+          } finally {
+            siblingBitmap.close();
+          }
+          if (encoded.sourceBelowFloor) throw new Error('PNG size floor: shorter side is below 800 px');
+          batchApply[index] = { status: 'ok', inventoryPng: encoded.blob };
+        } catch (error) {
+          const message = error instanceof Error ? error.message : 'unable to process photo';
+          batchApply[index] = { status: 'error', message };
+        }
+      }
+      return { results, batchApply };
+    } finally {
+      bitmap.close();
+    }
+  };
+
   // Legacy drafts (pre-axisBbox, with heading) carry no usable axis state;
   // fall back to the mask's own bbox.
   const draftAxisBbox = (d: Draft) => d.axisBbox ?? d.mask.bbox;
@@ -375,12 +470,14 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
     try {
       const mask = await rederiveMask(source, d.maskParams, d.mask);
       if (d.stage === 'axis') {
-        set({ k: 'axis', source, approvedMask: mask, axis: axisFrom(draftAxisBbox(d), source.widthPx, source.heightPx, d) });
+        set({ k: 'axis', source, approvedMask: mask, axis: axisFrom(draftAxisBbox(d), source.widthPx, source.heightPx, d), lengthEighths: d.lengthEighths ?? 0, thicknessEighths: d.thicknessEighths ?? 0 });
         return;
       }
-      if (d.inventoryPng) {
+      // A resultless legacy measure draft predates the merged tape page. Do not
-        if (pngUrl) URL.revokeObjectURL(pngUrl);
+      // open the result-only screen; return to tape calibration with its inputs.
-        pngUrl = URL.createObjectURL(d.inventoryPng);
+      if (d.stage === 'measure' && !d.results) {
+        set({ k: 'axis', source, approvedMask: mask, axis: axisFrom(draftAxisBbox(d), source.widthPx, source.heightPx, d), lengthEighths: d.lengthEighths ?? 0, thicknessEighths: d.thicknessEighths ?? 0 });
+        return;
       }
       set({
         k: 'measure', source, approvedMask: mask,
@@ -414,7 +511,7 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
     void persist();
   };
 
-  return {
+  const session: CaptureSession = {
     capture,
     busy,
 
@@ -514,7 +611,7 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
       teardownWorker();
       const overlay = state.overlay;
       const bbox = { corners: overlay.bbox.corners.map((c) => [...c] as [number, number]), longSidePx: overlay.bbox.longSidePx, angleDeg: overlay.bbox.angleDeg };
-      set({ k: 'axis', source: state.source, approvedMask: overlay, axis: axisFrom(bbox, state.source.widthPx, state.source.heightPx) });
+      set({ k: 'axis', source: state.source, approvedMask: overlay, axis: axisFrom(bbox, state.source.widthPx, state.source.heightPx), lengthEighths: 0, thicknessEighths: 0 });
       void persist();
     },
 
@@ -563,107 +660,54 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
       void persist();
     },
 
-    // #62: Calculate the calibration photo, then apply its frozen mask params
+    // Legacy compatibility path; the shipped tape page calls calculateFromAxis.
-    // to siblings. This stays in Measure; siblings never enter Mask controls.
     async calculate() {
       if (state.k !== 'measure') return;
-      const { source, approvedMask, axis, lengthEighths, thicknessEighths } = state;
+      const input: CalibrationInput = {
-      if (lengthEighths === 0 || thicknessEighths === 0) return;
+        source: state.source,
-      const bitmap = await decodeOrientedBitmap(source.blob);
+        approvedMask: state.approvedMask,
-      const base = measure(
+        axis: state.axis,
-        approvedMask.bitset, source.widthPx, source.heightPx,
+        lengthEighths: state.lengthEighths,
-        axis.bbox, lengthEighths, thicknessEighths, approvedMask.slabPx,
+        thicknessEighths: state.thicknessEighths,
-        { start: axis.tapeStart, end: axis.tapeEnd },
-      );
-      let pngBlob: Blob;
-      let belowFloor = false;
-      try {
-        const r = await encodeInventory({ bitmap, mask: approvedMask, source, cropFill });
-        pngBlob = r.blob;
-        belowFloor = r.sourceBelowFloor;
-      } catch {
-        // CAPTURE.md: inventory is image/png even when encode is unavailable.
-        pngBlob = new Blob([], { type: 'image/png' });
-      }
-      bitmap.close();
-      if (pngUrl) URL.revokeObjectURL(pngUrl);
-      pngUrl = URL.createObjectURL(pngBlob);
-
-      // #63: second copy of the calibration inventory PNG with dimension overlays.
-      // Keep clean inventoryPng untouched; never stash overlay into batchApply[cal].
-      let overlayBlob: Blob;
-      try {
-        overlayBlob = await encodeOverlay({
-          inventoryPng: pngBlob,
-          bitset: approvedMask.bitset,
-          widthPx: source.widthPx,
-          heightPx: source.heightPx,
-          bbox: axis.bbox,
-          scale: base.scale,
-          lengthIn: eighthsToIn(lengthEighths),
-          lengthLabel: fmtEighths(lengthEighths),
-          slabBounds: approvedMask.slabBounds,
-          source,
-          cropFill,
-        });
-      } catch {
-        // Deterministic tests may inject a non-decodable inventory blob; still
-        // return a distinct image/png so callers never confuse it with clean.
-        overlayBlob = new Blob(['overlay'], { type: 'image/png' });
-      }
-      const results: Measures = {
-        ...base,
-        inventoryPng: pngBlob,
-        overlayPng: overlayBlob,
-        sourceBelowFloor: belowFloor,
       };
-      const params = approvedMask.params;
+      const output = await runCalibration(input);
-      const calIndex = calibrationIndex != null && calibrationIndex >= 0
+      if (state.k !== 'measure') return;
-        ? calibrationIndex
+      set({ ...state, ...output });
-        : 0;
+      void persist();
-      const batch = batchPhotos.length ? batchPhotos : [source];
+    },
-      const batchApply: BatchPhotoResult[] = batch.map((_, index) => (index === calIndex ? null : {
-        status: 'error',
-        message: 'Batch photo was not processed',
-      }));
 
-      // Process serially so each worker owns exactly one sibling photo and a
+    async calculateFromAxis(lengthEighths, thicknessEighths) {
-      // failing decode/mask/encode cannot prevent later siblings from running.
+      if (state.k !== 'axis') return;
-      for (let index = 0; index < batch.length; index++) {
+      const length = Math.max(0, Math.round(lengthEighths));
-        if (index === calIndex) continue;
+      const thickness = Math.max(0, Math.round(thicknessEighths));
-        const photo = batch[index];
+      if (length === 0 || thickness === 0) return;
-        try {
+      if (poseTimer) {
-          const derived = await rederiveMaskDetailed(photo, params, {
+        clearTimeout(poseTimer);
-            slabPx: 0,
+        poseTimer = null;
-            bbox: EMPTY_BBOX,
-            slabBounds: EMPTY_ABOX,
-          });
-          if (derived.mask.slabPx === 0) {
-            throw new Error('empty mask: no slab pixels detected');
       }
-          const siblingSource: Source = {
+      const input: CalibrationInput = {
-            ...photo,
+        source: state.source,
-            widthPx: derived.widthPx,
+        approvedMask: state.approvedMask,
-            heightPx: derived.heightPx,
+        axis: state.axis,
+        lengthEighths: length,
+        thicknessEighths: thickness,
       };
-          const siblingBitmap = await decodeOrientedBitmap(photo.blob);
+      // Keep the tape page mounted while the PNG, overlay, and batch apply run.
-          let encoded: { blob: Blob; sourceBelowFloor: boolean };
+      // The old measure form was a real screen; the result state is not entered
-          try {
+      // until there is something complete to show.
-            encoded = await encodeInventory({ bitmap: siblingBitmap, mask: derived.mask, source: siblingSource, cropFill });
+      set({ ...state, lengthEighths: length, thicknessEighths: thickness });
-          } finally {
+      const output = await runCalibration(input);
-            siblingBitmap.close();
+      if (state.k !== 'axis') return;
-          }
+      set({
-          if (encoded.sourceBelowFloor) {
+        k: 'measure',
-            throw new Error('PNG size floor: shorter side is below 800 px');
+        source: input.source,
-          }
+        approvedMask: input.approvedMask,
-          batchApply[index] = { status: 'ok', inventoryPng: encoded.blob };
+        axis: input.axis,
-        } catch (error) {
+        lengthEighths: input.lengthEighths,
-          const message = error instanceof Error ? error.message : 'unable to process photo';
+        thicknessEighths: input.thicknessEighths,
-          batchApply[index] = { status: 'error', message };
+        results: output.results,
-        }
+        batchApply: output.batchApply,
-      }
+      });
-
-      set({ ...state, results, batchApply });
       void persist();
     },
 
@@ -682,14 +726,17 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
         const m = state.approvedMask;
         set({ k: 'mask', source: state.source, control: m.params, overlay: m, failed: false });
       } else if (state.k === 'measure') {
-        set({ k: 'axis', source: state.source, approvedMask: state.approvedMask, axis: state.axis });
+        set({
+          k: 'axis',
+          source: state.source,
+          approvedMask: state.approvedMask,
+          axis: state.axis,
+          lengthEighths: state.lengthEighths,
+          thicknessEighths: state.thicknessEighths,
+        });
       }
     },
 
-    getInventoryUrl() {
-      return pngUrl;
-    },
-
     currentMeasure() {
       return state.k === 'measure' ? state : null;
     },
@@ -698,6 +745,7 @@ export function createCaptureSession(opts: SessionOpts = {}): CaptureSession {
       teardownWorker();
     },
   };
+  return session;
 }
 
 // Display helper: format eighths as inches with fractions.

frontend/tests/e2e/artifacts/README.md

@@ -28,8 +28,8 @@ Fixtures: `tests/fixtures/set1-48x2/` (L=48, thickness=2) and `set2-31x2p5/` (L=
 | `01-batch.png` | Batch with fixtures loaded |
 | `02-pick-calibration.png` | Pick calibration |
 | `03-mask.png` | Mask (Black sheet) ready to approve |
-| `04-axis.png` | Length axis |
+| `04-axis.png` | Tape calibration page |
-| `05-measure.png` | Measure with L / thickness filled |
+| `05-tape-calibration.png` | Length and thickness entered on the tape page |
 | `06-photos-ready.png` | Photos ready lineup (clean + overlay + siblings) |
 
 Large regenerating `*.png` and Playwright `test-results/` / `playwright-report/` are gitignored.

frontend/tests/e2e/helpers/draft.ts

@@ -1,5 +1,5 @@
 // e2e helper: seed an in-progress device draft (stage='measure', with results) so
-// the Resume path restores straight to the Photos-ready Measure step — the
+// the Resume path restores straight to the Photos-ready result step — the
 // deterministic driver for the create→review→publish flow (no live camera/canvas
 // in e2e). The draft is written to the real idb-keyval DB ('keyval-store'/'keyval',
 // key 'slabuploader-draft') exactly as `saveDraft` would, so `resumeProbe` +

frontend/tests/e2e/photos-ready.spec.ts

@@ -64,7 +64,7 @@ const prepareMaskForApprove = async (page: Page) => {
 };
 
 test.describe('M2 #65 Photos-ready e2e (set1-48x2)', () => {
-  test('batch → pick → mask → axis → measure → photos ready + screenshots', async ({ page }) => {
+  test('batch → pick → mask → tape calibration → photos ready + screenshots', async ({ page }) => {
     test.setTimeout(180_000);
     expect(fs.existsSync(FACE_A), 'fixture face-a').toBeTruthy();
     expect(fs.existsSync(FACE_B), 'fixture face-b').toBeTruthy();
@@ -87,20 +87,16 @@ test.describe('M2 #65 Photos-ready e2e (set1-48x2)', () => {
     await shot(page, '03-mask.png');
     await page.getByRole('button', { name: 'Approve mask' }).click();
 
-    await expect(page.getByRole('heading', { name: 'Length axis' })).toBeVisible();
+    await expect(page.getByRole('heading', { name: 'Length' })).toBeVisible();
+    await expect(page.getByRole('heading', { name: 'Measure' })).toHaveCount(0);
     await shot(page, '04-axis.png');
-    await page.getByRole('button', { name: 'Approve axis' }).click();
-
-    await expect(page.getByRole('heading', { name: 'Measure' })).toBeVisible();
-    await page.getByLabel('Length L').fill('48');
-    await page.getByLabel('Thickness').fill('2');
-    // blur/change commits eighths into session before Calculate.
-    await page.getByLabel('Length L').blur();
-    await page.getByLabel('Thickness').blur();
-    await shot(page, '05-measure.png');
 
     const calc = page.getByRole('button', { name: 'Calculate' });
+    await expect(calc).toBeDisabled();
+    await page.getByLabel('Length L').fill('48');
+    await page.getByLabel('Thickness').fill('2');
     await expect(calc).toBeEnabled();
+    await shot(page, '05-tape-calibration.png');
     await calc.click();
 
     // Calculate encodes calibration PNG + overlay + sibling batch apply.
@@ -117,7 +113,7 @@ test.describe('M2 #65 Photos-ready e2e (set1-48x2)', () => {
 
     // Write a short run log for parent AI visual review (not a substitute for eyes).
     const logPath = path.join(ARTIFACTS, 'run-log.txt');
-    const shots = ['01-batch.png', '02-pick-calibration.png', '03-mask.png', '04-axis.png', '05-measure.png', '06-photos-ready.png'];
+    const shots = ['01-batch.png', '02-pick-calibration.png', '03-mask.png', '04-axis.png', '05-tape-calibration.png', '06-photos-ready.png'];
     const lines = [
       `M2 #65 Playwright e2e — set1-48x2 (L=48, thickness=2)`,
       `baseURL: ${page.url().split('/').slice(0, 3).join('/')}`,