Fix: iccV5DspObsToV4Dsp emits rXYZ/gXYZ/bXYZ as XYZType, not s15Fixed16ArrayType (#1362)

[colourbill-ctrl]

Closes #1362.

Problem

iccV5DspObsToV4Dsp created the red/green/blue matrix-column tags (rXYZ/gXYZ/bXYZ, a.k.a. red/green/blueColorantTag) as CIccTagS15Fixed16, which serializes with the type signature 'sf32' (s15Fixed16ArrayType). ICC.1 §9.2.46 / §9.2.31 / §9.2.4 require these tags to be XYZType ('XYZ ', §10.31) — an array of one XYZNumber.

The numeric data was correct (XYZType and a 3-element s15Fixed16ArrayType share the same 20-byte layout), but the wrong type signature made the profile NonCompliant and unreadable by consumers keying on the spec type — e.g. dynamic_cast<CIccTagXYZ*>(FindTag(icSigRedMatrixColumnTag)) returned nullptr in the PAWG quality metrics (IccQualityMetrics.h).

Fix

CIccTagXYZ* primaryXYZ = new CIccTagXYZ;            // 'XYZ ', one XYZNumber
(*primaryXYZ)[0].X = icDtoF(out[0]);
(*primaryXYZ)[0].Y = icDtoF(out[1]);
(*primaryXYZ)[0].Z = icDtoF(out[2]);
pIcc->AttachTag(icSigRedColorantTag, primaryXYZ);

(same for green/blue).

Verification

Regenerated LCDDisplayCat8Obs.icc from the committed inputs:

	Before	After
rXYZ/gXYZ/bXYZ on-disk type	sf32 (73663332)	XYZ (58595A20)
iccDumpProfile type	s15Fixed16ArrayType	XYZArrayType
colorant NonCompliant warning	Invalid tag type ×3	gone
red primary	—	X=0.5150 Y=0.2760 Z=-0.0035 (preserved)

A paired regression test (assert the three matrix-column tags serialize as 'XYZ ') will follow per the fix/test split.

🤖 Generated with Claude Code

[xsscx]

2026-06-15 22:00:24 UTC

[colourbill-ctrl]

Cross-reference for the archive: the regression guard for this fix had a detour. The paired test PR #1366 merged but its auto-merge silently dropped all four #1362 test artifacts (script, two .icc fixtures, CTest registration) when resolving the Testing/CMakeLists.txt conflict — so this producer fix (CIccTagXYZ / 'XYZ ') briefly sat on master with no regression test. It was restored via #1368 (00f04e1, 30 checks green). Master now carries the fix and the guard. Timeline on #1366.