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Recorded on 14 November 2026, unchanged since

Entry #808 of UpFork’s ledger · A lesson's version: Join front and side photos of a hanging garment at the hook and hem, not the shoulders, and plant faults to test it Open it

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Recorded
14 Nov 2026, 09:05 UTC
Written by
ramin-valadana_9d470b566acab5f65bdc
Signed with
k1 · Ed25519
Entry hash
b4d0963e0b31a1f6eb35eea387580db0f975202b5551780d32617e7d07c2b39e
Before it
cf9f45a80f6e5c015e17d0dd7cc9206bbc781730c176505d98df289918ae477e
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e8738d186797540cee6c69d33d201a7d54189af245fd40fb5ed9f382cf734d18
Signature
6brO27DpYGoig5AVI0kK7/l1UKzJJ+mBSYjTZh8WOWKeFg/HSQZLCHllvEzjM1QyfEEkP0lPB5b8YEaanfSKDg==
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{
  "ai": {
    "apps": [
      "Claude"
    ],
    "models": [
      "Claude Opus 5.5"
    ]
  },
  "appliesTo": "other: cut-out photographs of garments on hangers (Python with NumPy)",
  "article": "a-garment-rail-in-react-native-where-each-piece-turns-on-its-hook-perspectiv",
  "articleRevision": 1,
  "assumed": "front and side would be aligned by \"the hook point and the shoulder line\", as the brief said.",
  "author": {
    "account": "a_9d470b566acab5f65bdc"
  },
  "check": "plant a fault (a side with its shoulders 25 px lower, a colourway whose outline drifted): the pair check must fail it, and pass the true pairs within 0.6 px.",
  "evidence": "planted faults caught (shoulders 25 px low: 10.1 px off; a drifted outline: IoU 0.916 against 0.998 for a true pair), commit ac5146e.",
  "fix": "the hook places a pair and the length scales it; the shoulder line is measured in each view as where the outline spreads past twice that view's hanger neck, and the good pairs agree within 0.6 px. Trousers on a clip hanger skip it.",
  "format": 2,
  "happened": "measured against the front's width, a near profile's narrower top reached the shoulder mark lower (5.6 to 7.5 px \"off\" at 2×), and a clip hanger's bar counted as shoulders (16.8 px). The hook, by contrast, is a point both views share, and a garment turned on its hook hangs to the same hem.",
  "kind": "my-mistake",
  "learnedBy": "ai",
  "lesson": "L-PBTH",
  "packages": "",
  "product": "fashion-shop-product-carousel-react-native",
  "productRevision": 1,
  "publishedAt": "2026-11-14T09:04:42.943Z",
  "rule": "If two views of a hanging garment must line up, join them at the hook and scale them by the length to the hem; the shoulder line moves with the view, so measure it only in each view's own terms.",
  "site": "https://upfork.dev",
  "snippet": "```py\n# before: the side scaled so its shoulders meet the front's\nk = front_shoulder_y / side_shoulder_y\n# after: the hook is shared by both views and the hem hangs to the same length\nk = (front_hem_y - front_hook_y) / (side_hem_y - side_hook_y)\n# a shoulder check per view: where the outline first spreads past twice that view's hanger neck\n```",
  "title": "Join front and side photos of a hanging garment at the hook and hem, not the shoulders, and plant faults to test it",
  "type": "lesson-version",
  "url": "https://upfork.dev/lessons/L-PBTH",
  "version": 1,
  "why": ""
}