Levi Neuwirth
86635e43e1
ENGRAVER_VERSION 11 -> 12. The inter-staff solve now closes a slack pair as well
as opening a crowded one, realizing the InterStaffGap band's declared height
exactly. SYSTEM_STAFF_PITCH is demoted from a floor to an initial arrangement the
solve fully renegotiates. This is what vertical_density_penalty was reporting: an
un-pressured multi-staff system sat at 0.739, honest sprawl against the declared
gap, because the axis is symmetric and the solve only ever expanded.
The band's height had no agreed meaning, so pin it: it is an INK CLEARANCE -- the
separation between the two staves' outermost content, exactly the unit
req:qmc:vertical measures. preferred 2.0 -> 5.0, min 1.0 -> 2.0. The old 2.0 was
a placeholder reconciled with nothing: neither the 8.0 staff-box gap the fixed
pitch of 12 produces, nor the ~6.4 ink clearance it leaves for plain content.
Realizing it would have crushed a relaxed system to a pitch of ~7.6. At 5.0 plain
ledgered content settles near a pitch of 10.6.
Making the solve two-sided immediately exposed a CASCADE DEFECT latent since v11.
The recurrence subtracted the upper staff's shift from the measured gap and then
added it back through the accumulator, so every pair below the first was
over-separated by exactly the shift above it. Both staves move; the relation is
shift_lower = shift_upper + target - (upper_lo - lower_hi), the UNSHIFTED gap.
three_staff_close_content's lower pair realized 21.06 against a declared 4.0. It
was invisible on two-staff fixtures (shift_upper = 0) and invisible to
inter_staff_shifts_cascade_down_three_staves, which asserted only s2 > s1 -- true
under both the correct and the double-counting recurrence.
What caught it was the metric measuring realized clearance back from the BAKED
output instead of the solve's own extents. Reading back solver intent would have
reported 0 and shipped the over-separation again. That design choice was made one
commit earlier for exactly this reason; the catalog rationale now recommends it to
any conforming implementation.
Once the solve realizes each declared clearance exactly, every inter-staff unit is
0 on a healthy solve -- the axis becomes a solver self-check, and its MEAN can no
longer distinguish "measured every realization" from "measured one". So
vertical_raw is split into vertical_units and the regressions assert the unit SET.
Four mutations verified: the double-counting recurrence, expand-only, the
glyph-members band filter, and first-system-only measurement each fail a named test.
No normative change, no version move: QMC formula, units, anchors, thresholds all
untouched; only its non-normative rationale is refreshed. Churn is the two
multi-staff engrave goldens: two_staff grew by exactly 3.0 (the target change, no
cascade); three_staff SHRANK by 9.06 -- the same +3 per pair, less the 17.06 of
over-separation the defect was adding. Single-staff and every stub golden are
byte-stable.
The 5.0 was the user's call. 4.0 ("one staff height") was chosen first and
withdrawn once its true consequence -- pitch 9.57, not the 11.04 an arithmetic slip
of mine had projected -- was measured rather than inferred. The slip: deriving
plain-content ink clearance from an aggregate metric by assuming two contributing
units when it had three.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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| .. | ||
| src | ||
| Cargo.toml | ||
| DECISIONS.md | ||
| README.md | ||
README.md
epiphany-engrave
Agent I's engraving constraint solver (spec Chapter 9): turns a
ConstrainedLayoutIR into a ResolvedLayoutIR with real geometry. It is the
production-side replacement for epiphany-layout-ir's interface-only
StubSolver; the two live in separate crates so the spec's core/product boundary
stays sharp.
Status: Minimal tier, with casting-off
Engraverruns a deterministic horizontal spacing pass (the first axis of the two-pass spring layout): each spring slot is placed left-to-right by a collision-aware advance derived from real glyph bearings.- A casting-off pass (Phase 3's layout track) then breaks the spaced line
into systems at measure boundaries (greedy first-fit against a
PageGeometry— default A4 portrait at an 8 mm staff), stacks systems vertically at the vertical-band model's inter-system gap, assigns pages by content height, and populates the realResolvedPage/ResolvedSystemtree. Every position is baked into a single y-up world frame (pages stacked vertically), so the SVG renderer and hit-testing consume the flat glyph/stroke lists unchanged. - The IR's declared constraints are evaluated — geometric families against
the pre-casting spaced frame, break constraints against the final break
structure (hard breaks are always honoured; a pathological soft break is
skipped and recorded as an
IrOverridedecision). Chosen breaks are recorded asEngravingDecisions withSynthesisKind::EngravedBreaktargets, attributed to the user override that requested them when one did. - It reports
SolverTier::Minimal: hard constraints (break family included) satisfied, no optimality claim — the quality-metric vector stays the honest all-worst placeholder until the Quality Metric Catalog lands.
Deferred: the vertical soft-spring solve, per-system justification/stretch,
optimal break search, widow/orphan control, and casting-off caching. See
DECISIONS.md.
use epiphany_engrave::Engraver;
use epiphany_layout_ir::{ConstraintSolver, SolverConfig};
let report = Engraver::default().solve(&constrained_ir, &SolverConfig::default());
assert!(report.satisfied_hard_constraints);
let resolved = report.layout; // real pages/systems; hand to epiphany-render-svg