# Published ICC fixtures

These bytes are unmodified external profiles, not profiles generated by xgpui.
`manifest.json` records pinned upstream URLs, sizes and SHA-256 digests. Tests and
reference regeneration run offline. Retrieved 2026-10-30.

Eight profiles come from [Compact ICC Profiles](https://github.com/saucecontrol/Compact-ICC-Profiles/tree/bdd84663061bc4ae95ca70decff54f581e27f702),
commit `bdd84663061bc4ae95ca70decff54f581e27f702`. Upstream dedicates these
profiles to the public domain under CC0; its full license is in `CC0-1.0.txt`.
AdobeCompat is an independently authored compatible profile, not an Adobe file
or an assertion that its serialized transfer curve equals named Adobe RGB.

`sRGB2014.icc` is the ICC-authored profile mirrored by
[libavif](https://github.com/AOMediaCodec/libavif/blob/9b07a9d7a874b159bb4e14b80a6f08bb469d06f7/tests/data/sRGB2014.icc),
commit `9b07a9d7a874b159bb4e14b80a6f08bb469d06f7`. Its original copyright tag
is preserved. [ICC profile terms](https://www.color.org/profileview/#Licensing)
permit redistribution, embedding and use. No claim is made that this mirror is
byte-identical to a current download from the ICC registry. Its filename does
not identify its exact revision; the hash does.

| Fixture | Adapter result | Reason |
| --- | --- | --- |
| sRGB-v4, DisplayP3-v4, AdobeCompat-v4 | Accepted | Bounded RGB matrix/TRC profiles, shared exact TRC tag ranges |
| sRGB-v2-magic, DisplayP3-v2-magic, AdobeCompat-v2 | Rejected: Malformed | Strict range policy disallows other tags overlapping the declared desc range |
| sGrey-v4 | Rejected: Unsupported | Grayscale input |
| CGATS001Compat-v2-micro | Rejected: Unsupported | CMYK/LUT input |
| sRGB2014 | Accepted | Explicit relative PCS matrix with 1024-entry sampled curves |

The compact v2 files deliberately pack tag storage; the error classification
above describes our adapter policy, not a claim that these upstream files are
corrupt. They also encode historical v2 white-point conventions outside our
current explicit PCS-white contract; overlap rejection is the first boundary.

The pinned sRGB2014 colorant sums differ from its encoded PCS white by
`[5,-2,12]/65536`. That offset is preserved. `RgbDefinition::from_relative_xyz_matrix`
separates the declared XYZ reference white from the actual transform's neutral
ramp. It adapts the original matrix from the header PCS illuminant to D65 once,
without normalizing its columns or substituting the matrix sum as the CAT white.
Existing neutral-space constructors retain their 3/65536 admission bound.

Its informational `lumi`, `meas`, `bkpt`, `tech` and `vued` tags have a
4096-byte per-tag cap. They do not change relative matrix/TRC decoding: no
black-point compensation, absolute display luminance or viewing-condition
transform is applied. Neither media-white nor chad tags are reapplied to
already-PCS colorants. [ICC's explanation of D50 PCS and display whites](https://www.color.org/whyd50/)
provides context for the coordinate-system distinction. The byte-exact fixture
and independent secondary-engine check establish the retained offset here.

Four accepted profiles have 4,108 exact-tag reference vectors from 120-digit
Decimal arithmetic. These include near-black, mixed colors, endpoints, f32/f64
neighbors of serialized parametric thresholds, every sampled-curve knot and
its two f64 neighbors, and representative f32 knot neighbors. Curve and XYZ
tolerances remain 16/64 f64 epsilon scaled by decoded source energy. The
reference uses the encoded header PCS illuminant and applies PCS→D65 once.
It does not reapply chad, normalize matrices or substitute named curves.

```sh
python3 scripts/generate_real_icc_references.py --check
cargo test --offline --manifest-path extensions/crates/xgpui-color/Cargo.toml --features icc
```

Validation: all 42 color tests and 3 active doctests pass (one preexisting
illustrative doctest is ignored). Strict color-crate Clippy passes. The sibling
lab embeds the three accepted v4 files with their CC0 notice and the ICC-authored sRGB2014 with its original copyright and exercises
published metadata through the existing pixels-plus-metadata path.

Optional independent endpoint check (requires locally installed Little CMS 2):

```sh
python3 validation/icc-import-probe/check_srgb2014.py
```

Little CMS 2.19 agrees with the unnormalized PCS endpoints within a source-energy
scaled f32 budget, using relative colorimetric intent and no BPC/optimization.
This isolates matrix semantics; it does not replace the strict continuous f64
sampled-curve oracle or adopt a transform-engine dependency.

The relative-matrix constructor still rejects nonfinite, singular and poorly
conditioned matrices, invalid curves and invalid reference whites. It also
rejects an overflowed cofactor inversion that produces an all-zero inverse.
No precision budget was widened.

Follow-up: separately investigate compact-v2 packing and historical white
semantics. Do not infer general ICC, monitor-profile, LUT, grayscale or CMYK
support from these fixtures.