Casting-off's greedy first-fit + tail-only widow rebalance is replaced by a
deterministic badness-minimizing break search (optimal_breaks, a Knuth-Plass-
style dynamic program over the measure boundaries). ENGRAVER_VERSION 9 -> 10.
Objective: minimize the sum over ALL systems of the squared normalized underfill
((width_limit - w)/width_limit)^2. Squaring evens the systems; including the
FINAL system in the sum subsumes the old widow rebalance (the optimizer won't
leave a narrow final stub if a balanced partition is cheaper). It is the
additive, DP-tractable analog of the retired distribution_cost (max of the
catalog's break penalty and width-CV imbalance). On the ten-measure fixture the
search settles on 5/4 measures where greedy left a fuller-then-shorter split,
filling the final system more and pulling casting_off_quality down (~0.80 ->
~0.61) — the payoff, visible now that horizontal justification drives
system_break to ~0 so casting_off mostly sees the last system's fullness.
Break requirements (hard/soft/page) bound the DP's segments — a system may not
span a forced break — and walk_region still honours them and records skipped
content-less soft breaks as IrOverride, unchanged; optimal_breaks reports only
the automatic breaks. A system may exceed the width only as a single
unsplittable measure. Minimal still makes no optimality claim.
Deterministic: minimizes lexicographic (cost, system_count). Tests:
optimal_breaks_{balances_systems_and_avoids_a_final_widow, never_spans_a_forced_
break, is_deterministic_and_empty_when_unbounded}; the widow test now checks the
balanced measure distribution; wrapping-fixture metrics updated (casting_off
improved). Removed rebalance_widows/rebalance_region/distribution_cost + their
tests. Goldens regenerated (balanced systems; view_box stable — justification
still fills to width). 944 tests, clippy 0, docs -D warnings, conformance 8/8.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
An adversarial review of the justification commit found a SEVERE bug: stems
detach from their noteheads (~0.75 ss, up to ~1.5) in every justified system.
Root cause: the code used is_rigid_width_stroke to select slot-anchored strokes
on the false premise it covered stems. It is LEDGER-ONLY. A stem is an
Event-sourced stroke drawn at notehead_x + 1.15 with no same-source glyph
(noteheads are Pitch-sourced) and no baseline in its x-span, so it fell to the
affine branch and its intra-slot offset was scaled by the justification factor a,
floating it off its head into the gap. The spacing pass shared the same
classification (a smaller latent drift).
Fix: component_glyph classifies a stroke — a Staff (staff line) or
RepeatStructure (volta bracket, whose ending-number glyphs share its source)
source SPANS (affine); else owning_glyph (a ledger over its notehead, same Pitch
source); else the glyph with the greatest baseline <= the stroke's x — a stem's
own in-column notehead (stem_offset 1.15 < column step 1.6, so exactly its slot).
Applied in BOTH the spacing remap and casting, so stems ride their heads through
the whole pipeline. Ledgers are unchanged (owning_glyph path).
Regression: stem_offsets_from_the_notehead_survive_justification (verified to
fail without the fix). Goldens regenerated (stems now on their heads). The minor
slur-inset drift (same root cause, ~0.3 ss on a soft connector) is deferred with
a note. Folded into ENGRAVER_VERSION 8 (unreleased). 941 tests, clippy 0, docs
-D warnings, conformance 8/8.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Every non-final system of a multi-system region now stretches its horizontal
slack so its ink fills the content width, instead of sitting at its natural
left-aligned width. ENGRAVER_VERSION 7 → 8 (any wrapping score's baked geometry
differs; a single-system score is unchanged — its only system is ragged-right).
Casting bakes each system by a Placement: a vertical dy plus a horizontal affine
world_x = a·x + b (rigid = a:1, b:dx). A justified system spreads the slack
linearly (a = 1 + extra/span). The map is CLAMPED to the slot-source range: affine
within it, rigid slope-1 beyond it (bearing overhangs, staff lines drawn to the
ink edge), so the mapped ink extremes agree exactly with the per-slot deltas and
the ink spans exactly [left_margin, left_margin + content_width] (no over/under-
shoot). Slot-relative like the E1 remap: glyphs translate by the map at their
SLOT's source (intra-slot offsets survive), spanning strokes map endpoints through
the affine (they stretch), rigid-width strokes (stems/ledgers, via owning_glyph)
track their slot, slur control points map through the affine.
Not justified: a region's last system (ragged-right by convention), a degenerate
span, or a system already at/over width (never compressed into overlap).
Quality consequences (honest): system_break_penalty collapses to ~0 (the point);
the width-uniformity axes rise as the full non-final system contrasts with the
ragged last line (ten-measure casting_off ~0.45 → ~0.80) — a metric-semantics
follow-up noted in DECISIONS. Tests retargeted: the widow rebalance now shows in
measure distribution not baked widths; the floor-column test moved to a synthetic
vector (robust to fixture values). Goldens regenerated (view_box widens to the
content width; same 147 primitives, no collisions). 939 tests, clippy 0, docs
-D warnings, conformance 8/8.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
E2 drew every slur solid and surfaced a SlurLineStyleNotRendered diagnostic for
a non-Solid authored line. That deferral is now lifted: the Curve primitive
gains a `line: LineStyle` (from the slur's SpanStyle.line), threaded through the
resolved canonical encode (a per-curve style byte), the engrave remap, and
casting; render-svg emits stroke-dasharray (dashed = "0.5 0.35"; dotted =
round-capped "0 0.28"). The diagnostic variant is removed — the style is
rendered, not deferred, so `req:layoutir:slur-curve`'s "never silently rendered
solid" is satisfied by faithful rendering rather than a surfaced gap.
ENGRAVER_VERSION 5→6 (a dashed/dotted slur's resolved bytes and SVG differ).
Zero churn beyond the one dashed slur: the slur fixture's two solid curves are
byte-identical; only the editorial slur's <path> gained the dasharray. Solid
slurs and slur-free scores are unchanged. 932 tests, conformance 8/8.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The third pipeline primitive kind, review-hardened (5 verified findings fixed
pre-commit). A `Curve` (four control points, mirroring `Stroke`) threads
through all three IR stages, the canonical-encode fingerprint (a 5th u32 count
prefix; width-lock 4→5), the round-trip provenance chains and count identity,
`to_render`, the stub solver, engrave remap + casting, SVG path emission, and
hit-testing.
Slurs draw as one cubic bézier per slur carrying the slur's exact provenance
(no synthesis). LayoutContent::Slur resolves each endpoint event to a Note
column at to_logical (SlurEndpoint At/Unresolved — E1's honest-placement
discipline); a symmetric arc whose apex sits `height` from the endpoint line;
curvature_override direction+height honored, style.line (dashed) deferred to
Push 3. Honest non-drawing (traced anchor kept) for an unresolved endpoint, a
non-left-to-right span, or a cross-staff slur (no single staff — would float
at yo=0). Authored height/thickness sanitized to defaults when non-positive
(a negative thickness would else fail validation and blank the layout).
Hit-test: HitShape::Curve (Copy) flattens the cubic to a 16-segment capsule
inside contains/intersects (one region per curve); a slur click resolves to
Slur generically (no editor arm; edit ops refuse it). render-svg: stroked
unfilled <path C> after strokes/before glyphs + curve_count + content-hull
bounds. engrave: HorizontalRemap::curves; casting curve_system = Rigid-to-
start-system (no de Casteljau split — deferred; break-spanning slur draws
whole in its start system, kept for the source surjection); ENGRAVER_VERSION
4→5; slur_shape_penalty now 0.0 by construction (Minimal draws the ideal arc).
Existing SVG goldens changed only in the provenance-note comment (curves now
enumerated) — geometry byte-identical; 6 snapshots gained curve_count; new
ten_measure_with_slurs goldens. 929 tests, conformance 8/8.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Levi Neuwirth