chore: import upstream snapshot with attribution

skills/hyperframes-creative/scripts/contrast-report.mjs

@@ -0,0 +1,479 @@
+#!/usr/bin/env node
+// contrast-report.mjs — HyperFrames contrast audit
+//
+// Reads a composition, seeks to N sample timestamps, walks the DOM for text
+// elements, measures the WCAG 2.1 contrast ratio between each element's
+// declared foreground color and the ACTUAL pixels behind it, and emits:
+//
+//   - contrast-report.json  (machine-readable, one entry per text element × sample)
+//   - contrast-overlay.png  (sprite grid; magenta=fail AA, yellow=pass AA only, green=AAA)
+//
+// Usage:
+//   node skills/hyperframes-creative/scripts/contrast-report.mjs <composition-dir> \
+//     [--samples N] [--out <dir>] [--width W] [--height H] [--fps N]
+//
+// Env:
+//   HYPERFRAMES_SKILL_PKG_VERSION — pin the @hyperframes/producer version used
+//     when bootstrapping (global skill installs cannot infer it; falls back to
+//     @latest with a warning otherwise).
+//
+// The composition directory must contain an index.html. Raw authoring HTML
+// works — the producer's file server auto-injects the runtime at serve time.
+// Exits 1 if any text element fails WCAG AA.
+//
+// Background sampling: each sample time is captured TWICE — once via the
+// producer's normal (video-accurate) captureFrameToBuffer for the overlay
+// image, and once via a plain page.screenshot() taken right after hiding
+// every candidate element's own text paint (color/fill → transparent,
+// layout-neutral). The second capture reveals the REAL composited pixels
+// that were directly behind the glyphs, which this script then samples
+// straight from each element's own bbox — no proximity heuristic needed.
+// This is deliberately NOT routed through captureFrameToBuffer: that
+// pipeline has a static-frame dedup cache keyed by frame index/time that
+// knows nothing about our DOM mutation and would happily hand back a
+// cached pre-mutation buffer. A direct page.screenshot() bypasses that
+// entirely and is the same technique validated in
+// packages/cli/src/commands/contrast-audit.browser.js.
+//
+// The previous approach sampled a 4px ring just OUTSIDE the bbox, which
+// breaks down whenever what's immediately outside the text differs from
+// what's actually behind it: a neighboring panel/component just past the
+// text's edge, a backdrop-filter-blurred glass panel sized only a couple
+// pixels larger than the text, or a translucent decoration that only
+// partially overlaps the ring (or sits entirely inside the bbox, never
+// touching the ring at all).
+
+import { mkdir, writeFile } from "node:fs/promises";
+import { resolve } from "node:path";
+import { hyperframesPackageSpec, importPackagesOrBootstrap } from "./package-loader.mjs";
+
+// Use the producer's file server — it auto-injects the HyperFrames runtime
+// and render-seek bridge, so raw authoring HTML works without a build step.
+const packages = await importPackagesOrBootstrap(["@hyperframes/producer", "sharp"], {
+  npmPackages: [hyperframesPackageSpec("@hyperframes/producer"), "sharp@0.34.5"],
+});
+const sharp = packages.sharp.default;
+const {
+  createFileServer,
+  createCaptureSession,
+  initializeSession,
+  closeCaptureSession,
+  captureFrameToBuffer,
+  getCompositionDuration,
+} = packages["@hyperframes/producer"];
+
+// ─── CLI ─────────────────────────────────────────────────────────────────────
+
+const args = parseArgs(process.argv.slice(2));
+if (!args.composition) die("missing <composition-dir>");
+
+const SAMPLES = Number(args.samples ?? 10);
+const OUT_DIR = resolve(args.out ?? ".hyperframes/contrast");
+const WIDTH = Number(args.width ?? 1920);
+const HEIGHT = Number(args.height ?? 1080);
+const FPS = Number(args.fps ?? 30);
+const COMP_DIR = resolve(args.composition);
+
+// ─── Main ────────────────────────────────────────────────────────────────────
+
+await mkdir(OUT_DIR, { recursive: true });
+
+const server = await createFileServer({ projectDir: COMP_DIR, port: 0 });
+const session = await createCaptureSession(
+  server.url,
+  OUT_DIR,
+  { width: WIDTH, height: HEIGHT, fps: FPS, format: "png" },
+  null,
+);
+await initializeSession(session);
+
+try {
+  const duration = await getCompositionDuration(session);
+  const times = Array.from(
+    { length: SAMPLES },
+    (_, i) => +(((i + 0.5) / SAMPLES) * duration).toFixed(3),
+  );
+
+  const allEntries = [];
+  const overlayFrames = [];
+
+  for (let i = 0; i < times.length; i++) {
+    const t = times[i];
+    // Visible frame — used only for the human-facing overlay image.
+    const { buffer: pngBuf } = await captureFrameToBuffer(session, i, t);
+
+    // Hides each candidate's own text paint and returns its selector/fg/bbox.
+    const candidates = await prepareTextElements(session);
+    let elements;
+    try {
+      // Deliberately session.page.screenshot(), not captureFrameToBuffer —
+      // see the header comment for why.
+      const hiddenB64 = await session.page.screenshot({ encoding: "base64", type: "png" });
+      elements = await measureAgainstHiddenTextFrame(hiddenB64, candidates);
+    } finally {
+      await restoreTextElements(session);
+    }
+
+    const annotated = await annotateFrame(pngBuf, elements);
+    overlayFrames.push({ t, png: annotated });
+    for (const el of elements) allEntries.push({ time: t, ...el });
+  }
+
+  const report = {
+    composition: COMP_DIR,
+    width: WIDTH,
+    height: HEIGHT,
+    duration,
+    samples: times,
+    entries: allEntries,
+    summary: summarize(allEntries),
+  };
+
+  await writeFile(resolve(OUT_DIR, "contrast-report.json"), JSON.stringify(report, null, 2));
+  await writeOverlaySprite(overlayFrames, resolve(OUT_DIR, "contrast-overlay.png"));
+
+  printSummary(report);
+  process.exitCode = report.summary.failAA > 0 ? 1 : 0;
+} finally {
+  await closeCaptureSession(session).catch(() => {});
+  server.close();
+}
+
+// ─── DOM probe + text-hide (runs in the page) ────────────────────────────────
+
+// Walks the DOM for text-bearing elements, computes each one's foreground
+// paint, and hides that element's own text (color/fill → transparent,
+// !important, layout-neutral) so the caller's next screenshot reveals the
+// real pixels behind the glyphs. Returns the candidate list; call
+// restoreTextElements() afterward (in a finally) to undo the hide.
+async function prepareTextElements(session) {
+  return await session.page.evaluate(() => {
+    /** @type {Array<{selector: string, text: string, fg: [number,number,number,number], fontSize: number, fontWeight: number, bbox: {x:number,y:number,w:number,h:number}}>} */
+    const out = [];
+    const restores = [];
+    // Registered BEFORE the walk starts and pushed to incrementally as each
+    // element is hidden: if something in the walk throws partway through,
+    // everything hidden so far is still reachable for restore instead of
+    // leaking hidden indefinitely.
+    window.__contrastReportRestores = restores;
+    const walker = document.createTreeWalker(document.body, NodeFilter.SHOW_ELEMENT);
+    const parseColor = (c) => {
+      const m = c.match(/rgba?\(([^)]+)\)/);
+      if (!m) return [0, 0, 0, 1];
+      const parts = m[1].split(",").map((s) => parseFloat(s.trim()));
+      return [parts[0], parts[1], parts[2], parts[3] ?? 1];
+    };
+    // Like parseColor, but returns null instead of defaulting to black when
+    // the value isn't a solid rgb()/rgba() color — e.g. SVG paint keywords
+    // such as "none"/"context-fill", or a gradient/pattern reference like
+    // 'url("#grad")'. Callers should fall back to another source of truth
+    // rather than trust a fabricated black.
+    const tryParseSolidColor = (c) => {
+      const m = c.match(/rgba?\(([^)]+)\)/);
+      if (!m) return null;
+      const parts = m[1].split(",").map((s) => parseFloat(s.trim()));
+      if (parts.some((v) => Number.isNaN(v))) return null;
+      return [parts[0], parts[1], parts[2], parts[3] ?? 1];
+    };
+    // SVG text (<text>, <tspan>, <textPath>) is painted via the `fill`
+    // property, not `color` — the two are independent CSS properties in
+    // SVG. A page can set `fill` without ever touching `color`, in which
+    // case getComputedStyle(el).color resolves to the inherited/initial
+    // value (often black) and does not reflect what's actually rendered.
+    const isSvgTextElement = (el) => !!el.ownerSVGElement;
+    const selectorOf = (el) => {
+      if (el.id) return `#${el.id}`;
+      const cls = [...el.classList].slice(0, 2).join(".");
+      return cls ? `${el.tagName.toLowerCase()}.${cls}` : el.tagName.toLowerCase();
+    };
+    let el;
+    while ((el = walker.nextNode())) {
+      // must have direct text
+      const direct = [...el.childNodes].some(
+        (n) => n.nodeType === 3 && n.textContent.trim().length,
+      );
+      if (!direct) continue;
+      const cs = getComputedStyle(el);
+      if (cs.visibility === "hidden" || cs.display === "none") continue;
+      if (parseFloat(cs.opacity) <= 0.01) continue;
+      const rect = el.getBoundingClientRect();
+      if (rect.width < 8 || rect.height < 8) continue;
+      const isSvgText = isSvgTextElement(el);
+      const fg = isSvgText
+        ? tryParseSolidColor(cs.fill) || parseColor(cs.color)
+        : parseColor(cs.color);
+      if (fg[3] <= 0.01) continue;
+
+      // A `transition` on color/fill would otherwise animate this hide
+      // instead of applying it instantly — the screenshot taken right after
+      // can catch a partially-transparent glyph mid-transition instead of a
+      // fully hidden one, contaminating the background sample. Force
+      // `transition: none` alongside color/fill so the hide is atomic.
+      const origTransition = el.style.getPropertyValue("transition");
+      const origTransitionPriority = el.style.getPropertyPriority("transition");
+      el.style.setProperty("transition", "none", "important");
+      const origColor = el.style.getPropertyValue("color");
+      const origColorPriority = el.style.getPropertyPriority("color");
+      el.style.setProperty("color", "transparent", "important");
+      let origFill = null;
+      let origFillPriority = null;
+      if (isSvgText) {
+        origFill = el.style.getPropertyValue("fill");
+        origFillPriority = el.style.getPropertyPriority("fill");
+        el.style.setProperty("fill", "transparent", "important");
+      }
+      restores.push({
+        el,
+        origTransition,
+        origTransitionPriority,
+        origColor,
+        origColorPriority,
+        origFill,
+        origFillPriority,
+        isSvgText,
+      });
+
+      out.push({
+        selector: selectorOf(el),
+        text: el.textContent.trim().slice(0, 60),
+        fg,
+        fontSize: parseFloat(cs.fontSize),
+        fontWeight: Number(cs.fontWeight) || 400,
+        bbox: { x: rect.x, y: rect.y, w: rect.width, h: rect.height },
+      });
+    }
+    return out;
+  });
+}
+
+async function restoreTextElements(session) {
+  await session.page.evaluate(() => {
+    const restores = window.__contrastReportRestores;
+    if (!restores) return;
+    for (const r of restores) {
+      if (r.origColor) r.el.style.setProperty("color", r.origColor, r.origColorPriority);
+      else r.el.style.removeProperty("color");
+      if (r.isSvgText) {
+        if (r.origFill) r.el.style.setProperty("fill", r.origFill, r.origFillPriority);
+        else r.el.style.removeProperty("fill");
+      }
+      if (r.origTransition) {
+        r.el.style.setProperty("transition", r.origTransition, r.origTransitionPriority);
+      } else r.el.style.removeProperty("transition");
+    }
+    window.__contrastReportRestores = null;
+  });
+}
+
+// ─── Pixel sampling + WCAG math ──────────────────────────────────────────────
+
+// Samples the REAL composited background directly inside each candidate's
+// own bbox, from a screenshot taken with every candidate's text hidden —
+// robust to panel edges, backdrop-filter blur, and translucent decoration
+// in ways a proximity-based ring outside the bbox isn't. Mirrors
+// packages/cli/src/commands/contrast-sample.ts's computeSampleRect /
+// sampleGridPoints (kept in sync, not imported — this script bootstraps
+// npm-published packages and can't reach into the cli package's sources).
+async function measureAgainstHiddenTextFrame(hiddenImgBase64, candidates) {
+  const raw = Buffer.from(hiddenImgBase64, "base64");
+  const img = sharp(raw);
+  const { width, height } = await img.metadata();
+  const pixels = await img.ensureAlpha().raw().toBuffer();
+  const channels = 4;
+
+  const measured = [];
+  for (const c of candidates) {
+    const bg = sampleBboxMedian(pixels, width, height, channels, c.bbox);
+    if (!bg) continue;
+    const fg = compositeOver(c.fg, bg); // flatten any alpha against measured bg
+    const ratio = wcagRatio(fg, bg);
+    const large = isLargeText(c.fontSize, c.fontWeight);
+    measured.push({
+      selector: c.selector,
+      text: c.text,
+      fg,
+      fontSize: c.fontSize,
+      fontWeight: c.fontWeight,
+      bbox: c.bbox,
+      bg,
+      ratio: +ratio.toFixed(2),
+      wcagAA: large ? ratio >= 3 : ratio >= 4.5,
+      wcagAALarge: ratio >= 3,
+      wcagAAA: large ? ratio >= 4.5 : ratio >= 7,
+    });
+  }
+  return measured;
+}
+
+async function annotateFrame(pngBuf, elements) {
+  const { width, height } = await sharp(pngBuf).metadata();
+  // Draw boxes + ratio labels as an SVG overlay (sharp composite).
+  const svg = buildOverlaySVG(elements, width, height);
+  return await sharp(pngBuf)
+    .composite([{ input: Buffer.from(svg), top: 0, left: 0 }])
+    .png()
+    .toBuffer();
+}
+
+function sampleBboxMedian(raw, width, height, channels, bbox) {
+  // Sample the element's OWN box (glyphs are hidden in this frame), inset
+  // 1px on each side to dodge anti-aliased edge pixels, clamped to the
+  // frame bounds. A bounded grid, not a full scan, so a wide caption bar
+  // doesn't turn into thousands of samples.
+  const x0 = Math.max(0, Math.round(bbox.x) + 1);
+  const x1 = Math.min(width - 1, Math.round(bbox.x + bbox.w) - 1);
+  const y0 = Math.max(0, Math.round(bbox.y) + 1);
+  const y1 = Math.min(height - 1, Math.round(bbox.y + bbox.h) - 1);
+  if (x1 <= x0 || y1 <= y0) return null;
+
+  const stepX = Math.max(1, Math.floor((x1 - x0) / 12));
+  const stepY = Math.max(1, Math.floor((y1 - y0) / 6));
+  const r = [],
+    g = [],
+    b = [];
+  for (let y = y0; y <= y1; y += stepY) {
+    for (let x = x0; x <= x1; x += stepX) {
+      const i = (y * width + x) * channels;
+      r.push(raw[i]);
+      g.push(raw[i + 1]);
+      b.push(raw[i + 2]);
+    }
+  }
+  if (r.length === 0) return null;
+  return [median(r), median(g), median(b), 1];
+}
+
+function median(arr) {
+  const s = [...arr].sort((a, b) => a - b);
+  return s[Math.floor(s.length / 2)];
+}
+
+function compositeOver([fr, fg, fb, fa], [br, bg, bb]) {
+  return [
+    Math.round(fr * fa + br * (1 - fa)),
+    Math.round(fg * fa + bg * (1 - fa)),
+    Math.round(fb * fa + bb * (1 - fa)),
+    1,
+  ];
+}
+
+function relLum([r, g, b]) {
+  const ch = (v) => {
+    const s = v / 255;
+    return s <= 0.03928 ? s / 12.92 : ((s + 0.055) / 1.055) ** 2.4;
+  };
+  return 0.2126 * ch(r) + 0.7152 * ch(g) + 0.0722 * ch(b);
+}
+
+function wcagRatio(a, b) {
+  const la = relLum(a);
+  const lb = relLum(b);
+  const [L1, L2] = la > lb ? [la, lb] : [lb, la];
+  return (L1 + 0.05) / (L2 + 0.05);
+}
+
+function isLargeText(fontSize, fontWeight) {
+  return fontSize >= 24 || (fontSize >= 19 && fontWeight >= 700);
+}
+
+// ─── Overlay rendering ───────────────────────────────────────────────────────
+
+function buildOverlaySVG(elements, w, h) {
+  const rects = elements
+    .map((el) => {
+      const color = !el.wcagAA ? "#ff00aa" : !el.wcagAAA ? "#ffcc00" : "#00e08a";
+      const { x, y, w: bw, h: bh } = el.bbox;
+      return `
+        <rect x="${x}" y="${y}" width="${bw}" height="${bh}"
+              fill="none" stroke="${color}" stroke-width="3"/>
+        <rect x="${x}" y="${y - 18}" width="${48}" height="16" fill="${color}"/>
+        <text x="${x + 4}" y="${y - 5}" font-family="monospace" font-size="12" fill="#000">
+          ${el.ratio.toFixed(1)}:1
+        </text>`;
+    })
+    .join("");
+  return `<svg xmlns="http://www.w3.org/2000/svg" width="${w}" height="${h}">${rects}</svg>`;
+}
+
+async function writeOverlaySprite(frames, outPath) {
+  if (!frames.length) return;
+  const cols = Math.min(frames.length, 5);
+  const rows = Math.ceil(frames.length / cols);
+  const { width, height } = await sharp(frames[0].png).metadata();
+  const scale = 0.25;
+  const cellW = Math.round(width * scale);
+  const cellH = Math.round(height * scale);
+
+  const cells = await Promise.all(
+    frames.map(async (f) => ({
+      input: await sharp(f.png).resize(cellW, cellH).png().toBuffer(),
+      time: f.t,
+    })),
+  );
+
+  const composites = cells.map((c, i) => ({
+    input: c.input,
+    top: Math.floor(i / cols) * cellH,
+    left: (i % cols) * cellW,
+  }));
+
+  await sharp({
+    create: {
+      width: cols * cellW,
+      height: rows * cellH,
+      channels: 3,
+      background: { r: 16, g: 16, b: 20 },
+    },
+  })
+    .composite(composites)
+    .png()
+    .toFile(outPath);
+}
+
+// ─── Summary ────────────────────────────────────────────────────────────────
+
+function summarize(entries) {
+  const total = entries.length;
+  const failAA = entries.filter((e) => !e.wcagAA).length;
+  const passAAonly = entries.filter((e) => e.wcagAA && !e.wcagAAA).length;
+  const passAAA = entries.filter((e) => e.wcagAAA).length;
+  return { total, failAA, passAAonly, passAAA };
+}
+
+function printSummary({ summary, entries }) {
+  const { total, failAA, passAAonly, passAAA } = summary;
+  console.log(`\nContrast report: ${total} text-element samples`);
+  console.log(`  fail WCAG AA:     ${failAA}`);
+  console.log(`  pass AA, not AAA: ${passAAonly}`);
+  console.log(`  pass AAA:         ${passAAA}`);
+  if (failAA) {
+    console.log("\nFailures:");
+    for (const e of entries.filter((x) => !x.wcagAA)) {
+      console.log(`  t=${e.time}s  ${e.selector.padEnd(24)}  ${e.ratio.toFixed(2)}:1  "${e.text}"`);
+    }
+  }
+}
+
+// ─── Utilities ──────────────────────────────────────────────────────────────
+
+function parseArgs(argv) {
+  const out = {};
+  let positional = 0;
+  for (let i = 0; i < argv.length; i++) {
+    const a = argv[i];
+    if (a.startsWith("--")) {
+      const k = a.slice(2);
+      const v = argv[i + 1]?.startsWith("--") ? true : argv[++i];
+      out[k] = v;
+    } else if (positional === 0) {
+      out.composition = a;
+      positional++;
+    }
+  }
+  return out;
+}
+
+function die(msg) {
+  console.error(`contrast-report: ${msg}`);
+  process.exit(2);
+}