testsAndMisc/python_pkg/artgate
Krzysztof kuhy Rudnicki da8ca6d827
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artgate: deterministic exit-code gates for generated game art
Adds the route-independent spine of the planned art-generation bake-off: a
harness that decides whether generated art is well-formed, so "non-sloppy"
becomes machine-checkable instead of a judgement call.

Findings that shaped the design, all measured rather than assumed:

- Integer-scale invariance separates true pixel art (impurity 0.0000) from
  interpolated fakes (1.0000) exactly -- but passes trivially at scale 1, so
  it must never be trusted alone on native-resolution output.
- Gate ORDER is load-bearing. A soft-alpha image has no fully-opaque pixels,
  so an opaque-only colour count returns 0 and silently passes. ALPHA_NOT_BINARY
  now runs first and COLOR_COUNT fails closed on an empty opaque set.
- Counting must be over opaque RGB only: transparent pixels retain arbitrary
  RGB and inflated a naive RGBA count, rejecting correct art at 18/16.
- Declaring a gate was not enough to run it. hand_painted.toml shipped
  declaring SILHOUETTE_LOW_CONTRAST with no implementation, so it parsed, ran
  nothing, and reported a pass. load_spec now fails closed on unimplemented
  gates, result-only codes, and gates missing their config.

Thresholds are calibrated against 250 genuine 32x32 CC0 icons, not guessed:
p50=7 p90=13 p99=26 opaque colours; cap 32 rejects 0.0% of real art while raw
generator output measured 34403 colours. An initial cap of 16 wrongly rejected
a real DCSS icon -- re-derived from the corpus rather than nudged.

Verified: 57 tests, 100% branch coverage, zero suppressions, all hooks pass.
58/60 (96.7%) of real CC0 icons pass the full stack; both failures confirmed
true positives.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T9rQ12yZ7sJxiPQTCS5dUF
2026-08-15 22:20:36 +02:00
..
styles artgate: deterministic exit-code gates for generated game art 2026-08-15 22:20:36 +02:00
tests artgate: deterministic exit-code gates for generated game art 2026-08-15 22:20:36 +02:00
__init__.py artgate: deterministic exit-code gates for generated game art 2026-08-15 22:20:36 +02:00
cli.py artgate: deterministic exit-code gates for generated game art 2026-08-15 22:20:36 +02:00
codes.py artgate: deterministic exit-code gates for generated game art 2026-08-15 22:20:36 +02:00
contrast.py artgate: deterministic exit-code gates for generated game art 2026-08-15 22:20:36 +02:00
pixels.py artgate: deterministic exit-code gates for generated game art 2026-08-15 22:20:36 +02:00
spec.py artgate: deterministic exit-code gates for generated game art 2026-08-15 22:20:36 +02:00