From 3f6cc026dee74ec50e3cd91a84a22a0b9104d68d Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Sun, 25 Oct 2026 02:37:38 +0000
Subject: [PATCH 1/2] =?UTF-8?q?=EC=8B=9C=EC=9E=91=20=E2=80=94=2092?=
 =?UTF-8?q?=EB=B0=94=ED=80=B4?=
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Content-Type: text/plain; charset=UTF-8
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Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017uwozb36EhjHzHsJQiTQPU

From 225e0d1171319e360b64de9c118d84788d0ef30f Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Sun, 25 Oct 2026 02:41:17 +0000
Subject: [PATCH 2/2] web: fold the Pattern Lab's twice-written helpers into
 one each

The FNV-1a hash, the file download, commentSafe, roundRangeValue and
sortedLane each had two or three bodies; a new test pins the paste and
shader keys the hash files under.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017uwozb36EhjHzHsJQiTQPU
---
 web/src/app/pattern-lab/HardwareModal.tsx     | 17 +++-----
 web/src/app/pattern-lab/panels/KnobsPanel.tsx |  6 +--
 .../pattern-lab/panels/director/showFiles.ts  | 10 +----
 .../panels/director/useShowEditing.ts         |  6 +--
 web/src/lib/lab/capture/probe.ts              | 12 +-----
 web/src/lib/lab/capture/shaderStore.ts        | 12 +-----
 web/src/lib/lab/cppPrompt.ts                  |  6 +--
 web/src/lib/lab/director/bake.ts              |  2 +-
 web/src/lib/lab/flatten.ts                    |  2 +-
 web/src/lib/lab/hardwarePastes.ts             |  9 ++--
 web/src/lib/lab/hash.test.ts                  | 41 +++++++++++++++++++
 web/src/lib/lab/hash.ts                       | 14 +++++++
 web/src/lib/lab/pixelToCode.ts                |  7 +---
 web/src/lib/pattern/controls.ts               |  8 ++++
 14 files changed, 83 insertions(+), 69 deletions(-)
 create mode 100644 web/src/lib/lab/hash.test.ts
 create mode 100644 web/src/lib/lab/hash.ts

diff --git a/web/src/app/pattern-lab/HardwareModal.tsx b/web/src/app/pattern-lab/HardwareModal.tsx
index e9ff44ff1..632456ba5 100644
--- a/web/src/app/pattern-lab/HardwareModal.tsx
+++ b/web/src/app/pattern-lab/HardwareModal.tsx
@@ -12,6 +12,7 @@ import {
   cleanPastedUnit,
   enforcePatternName,
 } from "@/lib/lab/hExport";
+import { downloadBlob } from "@/lib/lab/capture/download";
 import { buildCppPrompt } from "@/lib/lab/cppPrompt";
 import { promptKey, readPastes, writePastes } from "@/lib/lab/hardwarePastes";
 import { currentPerformanceJson } from "@/lib/lab/director/publish";
@@ -197,17 +198,11 @@ export default function HardwareModal({
   const copyLabel = (key: string, idle: string) =>
     copied?.key === key ? (copied.ok ? "Copied ✓" : "Copy failed") : idle;
 
-  const downloadH = () => {
-    const blob = new Blob([assembled], { type: "text/plain" });
-    const url = URL.createObjectURL(blob);
-    const anchor = document.createElement("a");
-    anchor.href = url;
-    anchor.download = `${
-      exportData.namespaceName.replace(/^LabStack_/, "").toLowerCase() || "pattern"
-    }.h`;
-    anchor.click();
-    URL.revokeObjectURL(url);
-  };
+  const downloadH = () =>
+    downloadBlob(
+      new Blob([assembled], { type: "text/plain" }),
+      `${exportData.namespaceName.replace(/^LabStack_/, "").toLowerCase() || "pattern"}.h`,
+    );
 
   const label = lone?.name ?? name;
 
diff --git a/web/src/app/pattern-lab/panels/KnobsPanel.tsx b/web/src/app/pattern-lab/panels/KnobsPanel.tsx
index d5e3a11b0..f19ea70e6 100644
--- a/web/src/app/pattern-lab/panels/KnobsPanel.tsx
+++ b/web/src/app/pattern-lab/panels/KnobsPanel.tsx
@@ -10,7 +10,7 @@ import { useCallback, useEffect, useRef, useState } from "react";
 import { labEngine } from "@/lib/lab/engine";
 import { captureSession } from "@/lib/lab/capture/session";
 import { useLabStore } from "@/lib/lab/store";
-import { knobArrowValue } from "@/lib/pattern/controls";
+import { knobArrowValue, roundRangeValue } from "@/lib/pattern/controls";
 import local from "./KnobsPanel.module.css";
 import dock from "../LabPanels.module.css";
 
@@ -39,10 +39,6 @@ function formatRangeControlValue(value: number) {
   return value.toFixed(3);
 }
 
-function roundRangeValue(value: number) {
-  return Math.round(value * 1000) / 1000;
-}
-
 function getDigitStep(text: string, index: number) {
   const char = text[index];
   if (!char || char === "-" || char === ".") return null;
diff --git a/web/src/app/pattern-lab/panels/director/showFiles.ts b/web/src/app/pattern-lab/panels/director/showFiles.ts
index dbc49c3fc..3e853f345 100644
--- a/web/src/app/pattern-lab/panels/director/showFiles.ts
+++ b/web/src/app/pattern-lab/panels/director/showFiles.ts
@@ -4,20 +4,12 @@
 // blank title falls back to it, so the file downloads as <pattern>.pfs.
 
 import { encodePfst, pfsFilename, serializePerformance, validatePerformance } from "@/lib/pattern/pfst";
+import { downloadBlob } from "@/lib/lab/capture/download";
 import { bakeShowV2, showFromPerformance } from "@/lib/lab/director/bake";
 import { midiFilename, showToMidi } from "@/lib/lab/director/exporters/midi";
 import type { DirectorShow } from "@/lib/lab/director/types";
 import { readPerformanceFile } from "../../community";
 
-function downloadBlob(blob: Blob, filename: string) {
-  const url = URL.createObjectURL(blob);
-  const anchor = document.createElement("a");
-  anchor.href = url;
-  anchor.download = filename;
-  anchor.click();
-  URL.revokeObjectURL(url);
-}
-
 const named = (director: DirectorShow, patternName: string) =>
   director.title.trim() ? director : { ...director, title: patternName };
 
diff --git a/web/src/app/pattern-lab/panels/director/useShowEditing.ts b/web/src/app/pattern-lab/panels/director/useShowEditing.ts
index 4e4822609..d05b94448 100644
--- a/web/src/app/pattern-lab/panels/director/useShowEditing.ts
+++ b/web/src/app/pattern-lab/panels/director/useShowEditing.ts
@@ -4,7 +4,7 @@
 // panel's two keys (Delete, Space).
 
 import { useCallback, useEffect, useMemo, useRef, useState, type RefObject } from "react";
-import { resolveLane, resolvedLaneValue } from "@/lib/lab/director/bake";
+import { resolveLane, resolvedLaneValue, sortedLane } from "@/lib/lab/director/bake";
 import {
   DEFAULT_CURVE_CP,
   DIRECTOR_MAX_SECONDS,
@@ -29,10 +29,6 @@ export function interpOf(k: DirectorKeyframe): Interp {
   return k.h === "auto" ? "auto" : "manual";
 }
 
-function sortedLane(lane: DirectorKeyframe[]): DirectorKeyframe[] {
-  return [...lane].sort((a, b) => a.t - b.t);
-}
-
 export function useShowEditing({
   director,
   updateDirector,
diff --git a/web/src/lib/lab/capture/probe.ts b/web/src/lib/lab/capture/probe.ts
index 9ebaebc67..d54c9a67e 100644
--- a/web/src/lib/lab/capture/probe.ts
+++ b/web/src/lib/lab/capture/probe.ts
@@ -27,6 +27,7 @@
 
 import type { MatrixSize } from "@/lib/pattern/matrix";
 import { LabEngine } from "../engine";
+import { fnv1a } from "../hash";
 import type { CaptureProject } from "./types";
 import { stretchNearest } from "./core";
 import { isRasterLayer, type Layer } from "../types";
@@ -348,22 +349,13 @@ export function probeKey(project: CaptureProject): string {
     if (!layer.visible) continue;
     parts.push(
       layer.type === "code"
-        ? `c:${layer.id}:${layer.role}:${layer.maskInvert}:${layer.opacity > 0}:${layer.recolor}:${layer.code.length}:${hash(layer.code)}`
+        ? `c:${layer.id}:${layer.role}:${layer.maskInvert}:${layer.opacity > 0}:${layer.recolor}:${layer.code.length}:${fnv1a(layer.code)}`
         : `p:${layer.id}:${layer.role}:${layer.maskInvert}:${layer.opacity > 0}:${layer.rev}`,
     );
   }
   return parts.join("|");
 }
 
-function hash(text: string): number {
-  let h = 2166136261;
-  for (let i = 0; i < text.length; i++) {
-    h ^= text.charCodeAt(i);
-    h = Math.imul(h, 16777619);
-  }
-  return h >>> 0;
-}
-
 export function describeProbe(result: ProbeResult): string {
   switch (result.reason) {
     case "scales":
diff --git a/web/src/lib/lab/capture/shaderStore.ts b/web/src/lib/lab/capture/shaderStore.ts
index 23fea6de2..ac753f692 100644
--- a/web/src/lib/lab/capture/shaderStore.ts
+++ b/web/src/lib/lab/capture/shaderStore.ts
@@ -17,6 +17,7 @@
 // Bounded on purpose: the newest few, a couple of hundred KB. A shader lost to
 // pruning is one re-paste; a full quota breaks saving settings too.
 
+import { fnv1a } from "../hash";
 import { LAB_STORAGE, readJson, writeJson } from "../persist";
 
 const STORAGE_KEY = LAB_STORAGE.shader;
@@ -26,17 +27,8 @@ const MAX_TOTAL_CHARS = 200_000;
 type Entry = { source: string; at: number };
 type Store = Record<string, Entry>;
 
-function hash(text: string): number {
-  let h = 2166136261;
-  for (let i = 0; i < text.length; i++) {
-    h ^= text.charCodeAt(i);
-    h = Math.imul(h, 16777619);
-  }
-  return h >>> 0;
-}
-
 function keysFor(layerId: string, code: string): string[] {
-  return [`id:${layerId}`, `code:${hash(code)}`];
+  return [`id:${layerId}`, `code:${fnv1a(code)}`];
 }
 
 function read(): Store {
diff --git a/web/src/lib/lab/cppPrompt.ts b/web/src/lib/lab/cppPrompt.ts
index ad4eac962..95cbebc73 100644
--- a/web/src/lib/lab/cppPrompt.ts
+++ b/web/src/lib/lab/cppPrompt.ts
@@ -8,16 +8,12 @@ import {
   PATTERN_MATRIX_WIDTH,
   buildRampLUTRGBA,
 } from "@/lib/pattern/harness";
-import { knobDetentStep } from "@/lib/pattern/controls";
+import { knobDetentStep, roundRangeValue } from "@/lib/pattern/controls";
 import { withMatrixAnnotation, type MatrixSize } from "@/lib/pattern/matrix";
 import { codeUsesValueField } from "@/lib/pattern/ramp";
 import type { KnobRange, RampState } from "./types";
 import { rampStateToHarness } from "./engine";
 
-function roundRangeValue(value: number) {
-  return Math.round(value * 1000) / 1000;
-}
-
 type CppPromptArgs = {
   code: string;
   matrix: MatrixSize;
diff --git a/web/src/lib/lab/director/bake.ts b/web/src/lib/lab/director/bake.ts
index 03920bb51..b8db6ae3b 100644
--- a/web/src/lib/lab/director/bake.ts
+++ b/web/src/lib/lab/director/bake.ts
@@ -69,7 +69,7 @@ export function cubicBezierY(
   return sampleY(t);
 }
 
-function sortedLane(lane: DirectorKeyframe[]): DirectorKeyframe[] {
+export function sortedLane(lane: DirectorKeyframe[]): DirectorKeyframe[] {
   return [...lane].sort((a, b) => a.t - b.t);
 }
 
diff --git a/web/src/lib/lab/flatten.ts b/web/src/lib/lab/flatten.ts
index 4c8b2632c..3a8634e50 100644
--- a/web/src/lib/lab/flatten.ts
+++ b/web/src/lib/lab/flatten.ts
@@ -89,7 +89,7 @@ function stripForEmbedding(code: string): string {
 }
 
 /** A layer name inside a `//` comment: every line terminator JS knows, not just \n. */
-function commentSafe(name: string): string {
+export function commentSafe(name: string): string {
   return name.replace(/[\r\n\u2028\u2029]/g, " ");
 }
 
diff --git a/web/src/lib/lab/hardwarePastes.ts b/web/src/lib/lab/hardwarePastes.ts
index f6c0b388b..7d41d452d 100644
--- a/web/src/lib/lab/hardwarePastes.ts
+++ b/web/src/lib/lab/hardwarePastes.ts
@@ -16,6 +16,8 @@
 // record would wipe each other's pastes. A tab's record ends with the tab,
 // and nothing has to prune it.
 
+import { fnv1a } from "./hash";
+
 const KEY = "patternflow_lab_hardware_pastes_v1";
 
 /**
@@ -24,12 +26,7 @@ const KEY = "patternflow_lab_hardware_pastes_v1";
  */
 export function promptKey(prompt: string): string {
   const asked = prompt.replace(/, current [^,\n]*/g, "");
-  let h = 2166136261;
-  for (let i = 0; i < asked.length; i++) {
-    h ^= asked.charCodeAt(i);
-    h = Math.imul(h, 16777619);
-  }
-  return `${asked.length}:${(h >>> 0).toString(36)}`;
+  return `${asked.length}:${fnv1a(asked).toString(36)}`;
 }
 
 /** Every paste this tab kept, by the key of the prompt it answers. */
diff --git a/web/src/lib/lab/hash.test.ts b/web/src/lib/lab/hash.test.ts
new file mode 100644
index 000000000..08aee1aaa
--- /dev/null
+++ b/web/src/lib/lab/hash.test.ts
@@ -0,0 +1,41 @@
+// Until 25 October 2026 the Lab wrote its FNV-1a hash out three times
+// (capture/probe.ts, capture/shaderStore.ts, hardwarePastes.ts). Two of the
+// copies name what a browser keeps: the paste a tab files under its prompt,
+// and the shader filed under its pattern's source. Moving the hash to one
+// place must not move either key, or the next reload finds nothing there.
+
+import { beforeEach, describe, expect, it } from "vitest";
+import { loadShaderSource, saveShaderSource } from "./capture/shaderStore";
+import { promptKey } from "./hardwarePastes";
+import { fnv1a } from "./hash";
+import { LAB_STORAGE } from "./persist";
+
+const PROMPT = [
+  "- Knob 1: min 0, max 1, current 0.5, calibrated encoder step 0.01 per detent",
+  "- Knob 2: min 0, max 4, current 2, calibrated encoder step 0.083 per detent",
+].join("\n");
+
+describe("keys the Lab files under a hash", () => {
+  beforeEach(() => window.localStorage.clear());
+
+  it("is 32-bit FNV-1a", () => {
+    expect(fnv1a("")).toBe(0x811c9dc5);
+    expect(fnv1a("a")).toBe(0xe40c292c);
+    expect(fnv1a("foobar")).toBe(0xbf9cf968);
+  });
+
+  it("files a To hardware paste under the key it had", () => {
+    expect(promptKey(PROMPT)).toBe("128:1q359yv");
+    // Turning a knob is no reason to ask again, so the position stays out.
+    expect(promptKey(PROMPT.replace("current 0.5", "current 0.75"))).toBe("128:1q359yv");
+  });
+
+  it("files a shader under the source hash it had", () => {
+    const code = "function render(ctx) { return 0; }";
+    saveShaderSource("layer-a", code, "void main() {}");
+    const saved = JSON.parse(window.localStorage.getItem(LAB_STORAGE.shader) ?? "{}");
+    expect(Object.keys(saved).sort()).toEqual(["code:968204348", "id:layer-a"]);
+    // A reload mints new layer ids, and the hash finds the shader again.
+    expect(loadShaderSource("layer-b", code)).toBe("void main() {}");
+  });
+});
diff --git a/web/src/lib/lab/hash.ts b/web/src/lib/lab/hash.ts
new file mode 100644
index 000000000..ef9605ae2
--- /dev/null
+++ b/web/src/lib/lab/hash.ts
@@ -0,0 +1,14 @@
+// ── Short hash of a string ───────────────────────────────────────────────────
+// 32-bit FNV-1a over UTF-16 code units. Two of its callers file things in the
+// browser under it: a To hardware paste (hardwarePastes.ts) and a shader twin
+// (capture/shaderStore.ts). A change here orphans both, so hash.test.ts pins
+// their keys.
+
+export function fnv1a(text: string): number {
+  let h = 2166136261;
+  for (let i = 0; i < text.length; i++) {
+    h ^= text.charCodeAt(i);
+    h = Math.imul(h, 16777619);
+  }
+  return h >>> 0;
+}
diff --git a/web/src/lib/lab/pixelToCode.ts b/web/src/lib/lab/pixelToCode.ts
index 0e5476619..80334fb3e 100644
--- a/web/src/lib/lab/pixelToCode.ts
+++ b/web/src/lib/lab/pixelToCode.ts
@@ -25,7 +25,7 @@
 // canvas with a small drawing in it shrinks from ~44 KB to a few KB.
 
 import { withMatrixAnnotation } from "@/lib/pattern/matrix";
-import { rleEncodeRGBA } from "./flatten";
+import { commentSafe, rleEncodeRGBA } from "./flatten";
 import { bytesToBase64 } from "./serialize";
 import { activeTextEffect } from "./textEffects";
 import { fontLabel } from "./textFonts";
@@ -122,11 +122,6 @@ function asciiPreview(sprite: SpriteCrop): string[] {
   return rows;
 }
 
-/** A layer name inside a `//` comment: no line terminators. */
-function commentSafe(name: string): string {
-  return name.replace(/[\r\n\u2028\u2029]/g, " ");
-}
-
 const B64_DECODER = `function decodeB64(s, n) {
   const A = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
   const out = new Uint8ClampedArray(n);
diff --git a/web/src/lib/pattern/controls.ts b/web/src/lib/pattern/controls.ts
index d207b990a..da790caf3 100644
--- a/web/src/lib/pattern/controls.ts
+++ b/web/src/lib/pattern/controls.ts
@@ -56,6 +56,14 @@ export function tidyKnobValue(value: number) {
   return Number(value.toPrecision(12));
 }
 
+/**
+ * Three decimals, the grain of the Lab's knob range fields: an edge typed or
+ * dragged in the Knobs panel, and the detent step the C++ prompt quotes.
+ */
+export function roundRangeValue(value: number) {
+  return Math.round(value * 1000) / 1000;
+}
+
 /** The middle of a knob's range, where a card with no saved knob state starts. */
 export function knobMidpoint(range: readonly [number, number]) {
   return tidyKnobValue((range[0] + range[1]) / 2);