Viewing is open to everyone. Downloading and starring need a GitHub sign-in.
Sign in with GitHub
CKey-Format-v0.13.0.md
v0.1.0-build.85
Latest
Commit ede38f5
Sign in with GitHub to download. Each download is recorded with your GitHub username.
| 1 | # CKey locator format v0.13.0 (draft) |
| 2 | |
| 3 | Status: experimental. New locator frames use `format=13` (`0D`) and |
| 4 | `profile=1`; older locator formats remain decoder-readable for compatibility. |
| 5 | |
| 6 | ## External-corner finder geometry |
| 7 | |
| 8 | The canonical field is 29 by 29 units. Its finder geometry forms the **actual |
| 9 | convex outside corners of the symbol**, not marks inset inside a rounded |
| 10 | rectangle. The four straight frame sides run at coordinate `0.5` / `28.5` and |
| 11 | stop at the corner tangent points. Each finder is three round-capped quarter |
| 12 | arcs with common centre at the physical corner: `(0.5,0.5)` for top-left and |
| 13 | its reflections for the other corners. Centerline radii are 1.80, 2.65, and |
| 14 | 3.50 units; all strokes are 0.65 units. The 3.50-unit arc joins the structural |
| 15 | side segments and is therefore the rounded outer corner itself. |
| 16 | |
| 17 | Top-right, bottom-right, and bottom-left arc sets are continuous. Every |
| 18 | top-left arc has a cap-compensated 0.95-unit visible gap centered on the |
| 19 | 45-degree diagonal. That split is the orientation signature. The corner |
| 20 | envelopes remain reserved from payload. |
| 21 | |
| 22 | ## Remaining locator rules |
| 23 | |
| 24 | All other Format 0.8/0.12 locator rules remain: 16-byte payload; frame |
| 25 | `C7 4B 0D 01 00 10`, CRC-32C, systematic shortened RS(77,26) over GF(256) |
| 26 | with polynomial `0x11D`, 51 parity bytes, and up to 25 unknown byte-error |
| 27 | correction. Grid Key, Ray Key, Ring Key, Cartesian/polar placement, rings, |
| 28 | ray band, and logo-safe centre are unchanged. The reader uses keys and finder |
| 29 | geometry for optical fit but only accepts a result after RS and CRC validation. |
| 30 | |
| 31 | The normative vector is [`locator-v13.json`](../tests/vectors/locator-v13.json). |