feat(chrome): hand snapshots to context mode

2026-08-28 08:35:57 +00:00 · 2026-08-28 14:45:37 +08:00
parent 221e978622
commit f3a2abe1e4
96 changed files with 12800 additions and 26 deletions
@@ -0,0 +1,66 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>27 scroll momentum tail</title>
+<link rel="stylesheet" href="../_style.css">
+<script src="../_lib.js"></script>
+<body>
+<main>
+  <p>Goal: scroll the box to its bottom using a real wheel/trackpad gesture.
+     Page records the <code>deltaY</code> sequence and requires a momentum-like tail:
+     a peak <code>|deltaY|</code>, then a decreasing decay over several events
+     (≥4 wheel events whose <code>|deltaY|</code> is strictly less than the previous
+     by &gt;5%). Constant or single-shot wheel events (one big delta then nothing)
+     fail.</p>
+  <div id="box" style="height:200px;overflow:auto;border:1px solid #555;background:#fff;color:#111;padding:8px">
+    <div style="height:2400px">scroll me ⬇ … continues …</div>
+  </div>
+</main>
+<script>
+Challenge.init({ id: "scroll-momentum", instructions: "scroll the box to its bottom with a real gesture" });
+
+const box = document.getElementById("box");
+const deltas = []; // signed
+const tsLog = [];
+
+box.addEventListener("wheel", (e) => {
+  deltas.push(e.deltaY);
+  tsLog.push(e.timeStamp);
+  if (deltas.length > 200) { deltas.shift(); tsLog.shift(); }
+  Challenge.log("wheel", { dy: e.deltaY, isTrusted: e.isTrusted });
+  if (!e.isTrusted) Challenge.fail("wheel event isTrusted=false");
+}, { passive: true });
+
+box.addEventListener("scroll", () => {
+  if (box.scrollTop + box.clientHeight < box.scrollHeight - 2) return;
+  // We hit bottom. Analyze the deltaY trace.
+  if (deltas.length === 0) return Challenge.fail("reached bottom with zero wheel events");
+  if (deltas.length < 6) return Challenge.fail(`only ${deltas.length} wheel events (need ≥6 for momentum)`);
+
+  const abs = deltas.map(Math.abs);
+  // All same sign? Trackpad inertia keeps signs consistent.
+  const allSameSign = deltas.every(d => Math.sign(d) === Math.sign(deltas[0]));
+  if (!allSameSign) return Challenge.fail("wheel deltaY signs flip — not a continuous scroll gesture");
+
+  // All identical magnitudes? Robotic.
+  const allEqual = abs.every(a => Math.abs(a - abs[0]) < 0.01);
+  if (allEqual) return Challenge.fail(`all |deltaY|=${abs[0]} — no momentum`);
+
+  // Find peak and require decay tail after it.
+  const peakIdx = abs.indexOf(Math.max(...abs));
+  const tail = abs.slice(peakIdx);
+  let decays = 0;
+  for (let i = 1; i < tail.length; i++) {
+    if (tail[i] < tail[i-1] * 0.95) decays++;
+  }
+  Challenge.log("trace", { abs, peakIdx, decays });
+  if (decays < 3) return Challenge.fail(`only ${decays} decay steps after peak — no momentum tail`);
+
+  // Timestamps within the tail should span ≥150ms (real inertia lasts hundreds of ms).
+  const tailTs = tsLog.slice(peakIdx);
+  const span = tailTs[tailTs.length-1] - tailTs[0];
+  if (span < 100) return Challenge.fail(`momentum tail only spans ${span.toFixed(0)}ms`);
+
+  Challenge.pass(`${deltas.length} wheels, peak |dY|=${abs[peakIdx].toFixed(1)}, ${decays} decay steps over ${span.toFixed(0)}ms`);
+});
+</script>
+</body>