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Font oracle captures

This directory retains external observations for bounded font experiments. Captures are inputs to offline conformance gates; they do not make the external tool a build dependency or turn one fixture into a general format claim.

  • harfbuzz-14.4.0-ahem.json records static Ahem metadata from hb-info.
  • harfbuzz-14.4.0-material-symbols-variable.json records variable-axis metadata, named-instance count, five normalized 2.14 coordinate vectors, and seven shapes including a GSUB FeatureVariations boundary through HarfBuzz’s public C API and hb-shape. It also records horizontal advances and canonical 26.6 paths from HarfBuzz draw callbacks at every shaping location. Regenerate it with python3 tools/font/capture_harfbuzz_variable.py <font> and compare the exact font digest before review.
  • harfbuzz-14.4.0-hvar-truncated-map.json records nonzero horizontal advances from a valid truncated HVAR advance-index map. Regenerate it with python3 tools/font/capture_harfbuzz_hvar.py <font> and the exact fixture named in the capture. It does not establish MVAR, VVAR, side-bearing, or broad HVAR support.
  • harfbuzz-14.4.0-roboto-flex-mvar.json records global MVAR metrics and shaping at eight locations in the reproducible two-glyph OFL-1.1 Roboto Flex subset under fixtures/. Regenerate it with python3 tools/font/capture_harfbuzz_mvar.py <font>. The fixture provenance, license, preparation command, and exact source/derived digests are retained beside the font.
  • harfbuzz-14.4.0-noto-sans-variable.json and harfbuzz-14.4.0-recursive-variable.json record metadata, normalization, shaping, horizontal advances, global metrics, and unhinted outlines at four locations each. Their independently authored OFL-1.1 subsets, licenses, derivation commands, and exact source/output digests are retained under fixtures/.
  • cargo xtask gate-i-font-security runs five variable fixtures through structural gvar, HVAR, MVAR, item-variation-store, and STAT preflight. Its 38 checksum-repaired hostile mutations—including packed point/delta runs and explicit VVAR exclusion—and six allocation/time trials write target/variable-font-security-report.json; the measured ceilings are reference-implementation regressions, not portable format limits.
  • cargo xtask gate-i-font-package validates the proposed asset metadata and policy for the OFL fixture, proves resource-only embedded package fixpoint and exact-byte retention across an unrelated edit, and exercises explicit digest-pinned linked resolution. Typed package binding remains deliberately rejected until the runtime consumes the same normalized coordinates.
  • cargo xtask gate-i-font-corpus compares both OFL subsets against the pinned HarfBuzz captures. It requires exact shaping, HVAR advances, MVAR metrics and path topology, with at most the measured one-unit 26.6 outline tie.
  • cargo xtask gate-i-font-gvar-generated rebuilds ephemeral checksummed sfnt values around a 300-point glyph. Sixteen accepted and three rejected trials cover the declared packed point/count/run/delta boundaries through the production whole-font inspector, including the 32,767 maximum point count.

The variable fixture comes from font-test-data 0.9.1. Its package metadata declares MIT OR Apache-2.0, while the font’s embedded copyright string is retained as a separate policy fact. Neither the capture nor parser acceptance is a license or redistribution determination.

Canonical source.