Lands the renderer-against-stub slice of Agent I's visible engraving work
(spec/PHASE2_QUICKSTART.md). Two new crates; prerequisites (G Pass 11, H
spelling/decomposition) are in place. Real engraving + Minimal-tier solver
follow next phase.
epiphany-render-svg (the deliverable this phase):
- Renders a ResolvedLayoutIR to well-formed SVG 1.1, drawing each glyph as a
GENUINE Bravura SMuFL outline <path>. Outlines are extracted reproducibly
from the official OFL Bravura.otf by a committed generator
(tools/extract_bravura_outlines.py, OFL.txt); the font is not vendored, only
the generated Rust (src/outlines_generated.rs). Staff-space/y-up coords with
one global y-flip wrapper; viewBox in staff spaces, px scale on the root.
- Non-overreach: every element traces to a ResolvedGlyph (data-prov) or a
declared wrapper; a glyph lacking an outline is surfaced as a diagnostic and
drawn as a fallback rect, never silently dropped.
- Hand-rolled xml::check_well_formed (no XML dep); acceptance tests cross-check
with system xmllint when present.
- examples/render_fixture.rs demo (fixture name -> SVG stdout, --solver=stub|real).
- Golden-locked machine acceptance snapshot + full-SVG golden for
ten_measure_single_staff and valid_score_rich; deterministic output.
epiphany-engrave (honest scaffold):
- Engraver: a deterministic horizontal-spacing pass (first axis of the planned
two-pass spring layout). Reports SolverTier::Stub — NOT Minimal — until it
evaluates the declared hard constraints, guarded by a regression test. The
demo's --solver=real exercises it end to end.
Honesty notes (recorded as Pass-12 candidates P12-I1..I3 in spec/PASS12_BATCH.md
and the crates' DECISIONS.md): the v0 to_logical/to_constrained pipeline is a
structural placeholder (arbitrary glyph per object, y=0), so stub output is not
yet recognizable notation and the QUICKSTART human visual gate is a next-phase
gate; MUSCLOID layout-id derivation stays unwired; bundled BRAVURA_METRICS are
approximations that disagree with the real outlines.
Gates: cargo fmt + clippy -D warnings clean; cargo test --workspace 504 passed,
0 failed, 0 ignored (criterion 6 layout round-trip still green).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Implements Agent E per spec/QUICKSTART.md — the layout intermediate
representation (Chapter 7) and the constraint-solver interface (Chapter 9):
* Four IR stages: LogicalLayoutIR -> ConstrainedLayoutIR ->
ResolvedLayoutIR -> RenderIR (interface only), with the composite-object
taxonomy, spring slots/constraints, vertical-band model, pages/systems,
engraving decisions + overrides, and the incremental dependency/cache model.
* TimeAxisModel tagged enum (Metric/Proportional/Aleatoric/Registered).
* Provenance back-references with manifestation- and synthesis-aware ids
((source, region) and (source, kind, ordinal)), so multiply-manifested and
synthesized objects never collide.
* In-tree Bravura GlyphCatalog (Send+Sync, metrics + render-data interface),
MUSCFNTM-tagged metrics hash with anchors hashed as a name-keyed map.
* Edit-barrier types keyed on OperationKindTag, with precise EditContext /
EditOracle scope/condition evaluation.
* StubSolver: returns SolveStatus::Solved with the input geometry verbatim;
spec-compliant SolveReport, Minimal tier + all-worst (unmeasured) metric
vector (no false conformance claim); rejects ill-formed input.
* f32 staff-space IR coordinates, quantized to the 1/1024 grid only at
canonical ResolvedLayoutIR serialization (Appendix D); non-finite geometry
is rejected, not normalized. Canonical encoding is injective in glyph
identity, provenance, engraving decisions, and catalog identity.
Re-points Agent F's testkit layout harness from its in-tree stub to the real
crate (v0 acceptance criterion 6) and expands its generators to E's public
surface. Expands Agent C's OperationKindTag to the full normative variant set
so edit barriers can prohibit every operation class.
Workspace gates green: fmt, clippy -D warnings, 377 tests, doc tests, rustdoc
-D warnings, and the conformance suite at scale 1. Decisions and Pass 11
candidates recorded in crates/epiphany-layout-ir/DECISIONS.md.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Levi Neuwirth