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CKey-Format-v0.15.0.md
v0.1.0-build.85
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| 1 | # CKey Format v0.15.0 — Profile 2 Text Capacity |
| 2 | |
| 3 | Status: experimental high-capacity profile. This revision emits `format=15` |
| 4 | (`0F`), `profile=2`. It supersedes Format 0.9.0 for new Profile 2 symbols; |
| 5 | decoders retain Format 0.9.0 readability. |
| 6 | |
| 7 | ## Frame and correction |
| 8 | |
| 9 | The frame before RS encoding is `C7 4B 0F 02 LLhi LLlo payload CRC32C`, then |
| 10 | deterministic zero padding through byte 209. Profile 2 carries 1–200 UTF-8 or |
| 11 | binary bytes in systematic RS(255,210) over GF(256), primitive polynomial |
| 12 | `0x11D`, primitive element 2, roots `alpha^0...alpha^44`. The 45 parity bytes |
| 13 | give the algebraic bound `2e + s <= 45`, including 22 unknown-byte errors. |
| 14 | |
| 15 | ## Canonical finder geometry |
| 16 | |
| 17 | The normalized field remains 29 by 29 units with centre `(14.5,14.5)`. The |
| 18 | outer boundary is a continuous 0.65-unit rounded square from `(0.5,0.5)` to |
| 19 | `(28.5,28.5)`, radius 3.5. Each corner has exactly **one** broad, round-capped |
| 20 | arc inside the border. In the top-left local corner its centre is `(4,4)`, |
| 21 | radius `2.30`, stroke width `0.80`, and its exterior-quadrant path runs from |
| 22 | `(1.70,4.0)` to `(4.0,1.70)`. Its concave/open mouth faces down-right into the |
| 23 | polar matrix. The other corners are reflected copies. Only the top-left arc is |
| 24 | split at 225 degrees, with a cap-compensated 0.95-unit visible gap. It is the |
| 25 | orientation signature. The 6 by 6 physical-unit corner envelopes remain |
| 26 | reserved. |
| 27 | |
| 28 | ## Density and placement |
| 29 | |
| 30 | The Cartesian matrix has a 58 by 58 density grid at 0.5-unit pitch and |
| 31 | 0.34-unit rounded-square modules. The central polar aperture (radius 10.5), |
| 32 | finders, and Grid Key are reserved. |
| 33 | |
| 34 | There are 144 equal angular slots, eight dot/arc rings at radii |
| 35 | `3.40 + 0.43*r`, and a narrow ray dial. Ring-bit runs of length one are dots; |
| 36 | runs of length at least two are one round-capped connected arc. The visible |
| 37 | length of a four-slot arc equals four adjacent dot slots exactly, while the arc |
| 38 | remains a distinct connected module. Rays use 0.52-unit short and 1.20-unit |
| 39 | long states. The Grid/Ray/Ring Keys retain their calibration roles. |
| 40 | |
| 41 | The native core has framing, RS correction, SVG rendering, and codeword tests. |
| 42 | It is not camera-validated; do not advertise Profile 2 as camera-scannable. |