Closes the two CPU-only cells of the art bake-off and builds the bridge the
diffusion cell will reuse.
Pins the bake-off to the SAME twelve subjects item-icons measured, with its
easy/hard split intact. Without this a route tested on distinctive silhouettes
beats the 6/12 baseline for free and the decision table means nothing. It also
makes the subject-routing rule falsifiable: a generator route is predicted to
lift specifically the six human-prior failures, and if it does not, the rule is
recorded as wrong.
Route (a) procedural: all twelve subjects drawn deterministically from a
7-colour locked palette. Every shape gets a distinguishing feature up front,
because item-icons measured that plain primitives read as placeholders however
correct the geometry is. Machine gate: 12/12 -- which proves "not malformed",
NOT quality. A procedural generator satisfies palette/alpha/canvas constraints
trivially; the human contact sheet is the real verdict.
Route (d) code-as-art: SVG emitted as text and rasterised by rsvg-convert, so
no new Python dependency (cairosvg/svgwrite stay absent).
The structural finding, measured on real rasteriser output rather than a
synthetic stand-in: raw vector renders pass 0/5 -- every one fails
ALPHA_NOT_BINARY, most also TOO_MANY_COLORS. After the finishing stage, 5/5.
Continuous-tone routes are therefore GENERATORS FEEDING A FINISHER, not
pixel-art generators. finish.py binarises alpha before quantising colour,
mirroring the gate order: quantising first blends transparent pixels' arbitrary
RGB into the palette.
Verified: 92 tests, 100% branch coverage across all ten modules, zero
suppressions, all hooks pass. The PLR2004 lint refactor was confirmed
pixel-neutral by byte-comparing all 12 icons before and after (12/12 identical).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T9rQ12yZ7sJxiPQTCS5dUF
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
