The two halves that touch live rendering, landed together because the
acceptance criteria that make either honest need both.
Suppression (Q#MS3/MS4/MS5/MS11). Detection runs in the per-line chunk
builder — the chunk-build path, never the edit path — and substitutes
each suppressed span's source bytes with ONE spacer chunk BEFORE tab
expansion, so a literal tab inside a span vanishes with it while tabs
outside keep their SourceTab provenance. The gate reads the EFFECTIVE
caret (own_cursor, which optimistic edits predict forward — F4's
no-flap requirement holds by construction) plus both own-selection
endpoints. Three motion paths can flip a gate without a content
change, and each now re-runs the per-line chunk compare, gated on a
one-scan "does the visible slice hold a $" check: the CursorByte arm,
finish_optimistic_edit (the text re-chunks under the OLD caret there;
without the hook a typed char rendered one keystroke stale), and the
Decorations arm — whose "no decoration change needs a reshape" premise
acquires exactly one exception, the Selection endpoints Q#MS11 made
suppression inputs.
The line-reuse predicate (acceptance 11, the #120 edge). Per-line
math state is cached in lockstep with line_chunk_cache: every detected
span with the gate bit it was built under. The scroll-reuse path
refuses a retained line whose cached bits disagree with the CURRENT
caret/selection — content is unchanged on every reuse path, so the
cached span set is authoritative and the gate bits are the only
variable. The acceptance test drives the stale-gate case through
rebuild_lines_reusing_scroll directly and fails if the gate is removed
from the predicate.
The hit map (B1'). hit_test_source_byte rebuilds its runs from a
whole-slice chunk walk, so it now reads the substitutions BACK from
the per-line caches — never re-planned under a possibly-newer caret —
keeping the map and the shaped glyphs one source of truth.
The draw pass (Q#MS6/MS7). Every MathItem::Glyph draws from its own
mini-buffer with Attrs pinned to the bundled math family (F8b), placed
at layout's exact x and the shaped line's REAL baseline; the
mini-buffer itself is positioned by the line_y cosmic-text actually
produced for it, so no font-metric rederivation can drift. Fraction
rules ride the bg quad batch after the decoration washes and under the
glyphs. Wash geometry gains Q#MS11's intersection rule: a wash
touching a suppressed span widens to the box's whole reserved
rectangle (a match strictly inside the span produced a zero-width
interval before), while the round-3 exclusive-end fix keeps a
non-intersecting wash off the box.
Acceptance (framing §5). Criteria 5-11 and 14-16 run on real pixels
through render_to_view: drawn ink where a literal-spacer control
renders none, with the before-region pixel-identical; the fraction
rule as a full-width run with operand ink both sides; caret-inside
rendering EXACTLY as math-disabled (driven through the real
CursorByte arm, which owns the refresh — a direct helper call would
not have pinned the wiring); every failure mode (unbalanced, unknown
command, $$, uncoverable glyph) pixel-equal to disabled; box clicks
snapping to the span start with the trailing edge landing after the
span; the scroll-reuse stale-gate bite; reflow confined to the
affected line with the after-text shifted by exactly the quantized
projection difference; selection gating and the whole-rectangle wash;
and the licence provenance pair. Criterion 17 is discharged
differentially: cargo tree -e features output for ttf-parser is
byte-identical with and without this crate's dependency line.
Also folded in, per the round-3 close-out: the F6 documenting test
($a$$b$ is eaten by the $$-opaque rule; one separating character
restores both spans), the depth-search bound raised 6 -> 8 so a
metric shift cannot make the "floor is dead code" expect fire with a
misleading message, the MathBox { end, .. } pattern nit, and the
active-work.md lane entry.
Named v0 approximations, deliberate: the peer-caret half of
acceptance 14 is pinned at the mapping level (unit tests), not
pixels; a soft-wrapped spacer draws its box whole at the first run's
origin (the one-rectangle model); the fit budget reads the bundled
code face even under a custom set_font family — the draw anchors to
the real shaped baseline either way, so only the fit margin is
approximate.
Clippy is CLEAN across the workspace at -D warnings for the first
time on this branch: the draw pass consumed every formerly-dead item,
and the three lints it could not fix (a test-only accessor, one doc
string, one manual midpoint) are fixed here.
Gates: cargo fmt --check; cargo clippy --workspace --all-targets
-- -D warnings; 1,815 default + 1,992 CRDT library tests; M4 121
(basedpyright skipped); 199 pmacs-gpu tests under PMACS_REQUIRE_GPU=1;
workspace sweep 3,131 across 88 suites (isolated XDG_CONFIG_HOME);
git diff --check.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
F1 was a real bug pinned by my own committed test. `end` in
ChunkSource::MathBox is EXCLUSIVE, so source position `end` is the first byte
AFTER the span — but the arm claimed it for the box's left edge, and the test
asserted that wrong value while calling the byte "interior". Consequences it
would have caused once overlays land: a search match starting just after a
span washes the whole box it does not intersect, violating Q#MS11; a peer
caret after the span draws at the box's left edge; caret geometry jumps
backwards. The same class existed in projected_to_source for a line-FINAL box,
where `within` clamps to the run length and the arm returned `start`
unconditionally, so a click past end-of-line landed on the span start. Both
committed hit tests put a chunk after the box, so that edge was never
exercised; there is now a test with the box last.
F2: parse_scripts peeked for the next marker without skipping whitespace, so
`x^2 _i` built a NESTED script — drawing the subscript displaced right by the
superscript's width — and `x^2 ^3` parsed where TeX errors, contradicting the
module's own "whitespace is insignificant" rule.
F3: layout is now fallible. A character the math font cannot draw used to
yield zero metrics and still emit a Glyph item, rendering tofu at zero advance
over its neighbour. Q#MS8's rule is "failure is always show the source", and
the draw pass needs a refusal signal — changed now, before that pass consumes
the API.
F4: the fraction gap was a hardcoded `thickness * 2.0` while the MATH table's
FractionNumeratorGapMin / FractionDenominatorGapMin went unread. Reading them
moved the flagship \frac{a}{b} from 0.732 to 0.867 and the fallback boundary
from depth 3 to depth 5. The round-2 review's hand-arithmetic estimate of
~0.85 was right; my 0.732 was inflated by the guess. The depth-SEARCHING test
absorbed the change without edits, which is the property it was written for.
F5: TeX's \epsilon and \phi are the lunate/symbol forms (U+03F5, U+03D5), not
U+03B5/U+03C6. Their italic mappings had to land with the seed change, since
both sit outside math_italic's U+03B1..03C9 run and would otherwise render
upright beside italic neighbours.
F7: the line-box budget derivation moved out of the test into
`line_box_budget`, so the draw pass and the acceptance test cannot compute
different splits while both stay green.
F8: the live-code clippy items are cleared. The 25 that remain are all
dead-code awaiting the draw pass.
189 pmacs-gpu tests pass.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The suppression mechanism F2 forced: a RichChunk's only width is its text, so
a suppressed span reserves room with SPACER SPACES the way SourceTab already
does, quantized up to whole advances. Quantizing up keeps the projection
grid-aligned with the surrounding monospace text and keeps hit runs integral,
at the cost of under one advance of slack on the right.
Adding the variant to an exhaustive enum made the compiler enumerate every
seam it must participate in, which is why it is wired through all five rather
than the two I had in mind: projected_to_source, source_to_projected, the tab
expander's source remap, and offset_chunk_source. Hits anywhere inside a box
snap to the span start — the Adornment rule, because Q#MS4 gives the box no
interior byte map — and source positions inside it collapse to the box's left
edge, so text after the span accounts for the whole reserved width.
Two details the tab expander needed: a math chunk's spacer text is generated
rather than source, so it holds no tab byte to expand, and its suppressed
range is already in slice coordinates and never split, so a within-chunk
offset does not move it.
spacer_for_width guards its inputs: a non-finite width, a non-positive
advance, or a pathological ratio reserves nothing or clamps, rather than
panicking or minting an enormous string from a cast.
184 pmacs-gpu tests pass, including the 155 that predate this branch.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
MathBox/MathItem composition for the Q#MS2 subset: characters advance a pen,
scripts shift by the MATH table's superscript/subscript amounts at script
scale, and \frac stacks its operands around a rule at the math axis. Inline
\frac sets its operands one style down, which is TeX's rule and also what the
parent framing's Tier 3 specifies — and it is load-bearing for Q#MS10, since
full-size operands would not fit the line at all.
The height budget is now measured rather than assumed, and the round-2 review
was right to insist on that. Two things were wrong.
First, my own test derived the budget from the MATH font's metrics. Q#MS10
says the budget is the LINE BOX, whose baseline the CODE font places —
JetBrains Mono ascends 16.32 px and descends 4.80 px at 16 px inside the 22 px
line, against Latin Modern Math's 12.90/3.10. Using the wrong font made a
plain \frac{a}{b} score 0.485 and appear to fall below the floor, which would
have meant the flagship case never rendering.
Second, with the budget derived correctly, B6 holds — \frac{a}{b} scales to
0.732 — but rev 3's guessed fallback case does not. A doubly-nested fraction
scores 0.744 and still renders; the floor is not tripped until depth 3, at
0.580. Round 2 predicted precisely this surprise-pass. Worth keeping: depth 2
scores HIGHER than depth 1, because the binding constraint flips from descent
to ascent as nesting grows asymmetrically, so "deeper is always tighter" is
false.
The test therefore SEARCHES for the tripping depth instead of hardcoding it,
and fails if no depth trips the floor at all — which would mean the fallback
arm is unreachable and the floor is dead code. Acceptance 12 records the
measured table.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Font, licence, and the metrics half of Tier 3.
The bundled font is Latin Modern Math under the GUST Font License, added as
fonts/GUST-FONT-LICENSE.txt — deliberately a separate file from fonts/OFL.txt,
which covers JetBrains Mono only. GFL is LPPL-derived, not the SIL OFL; the
framing's F6 corrected that error and this is the discharge. At 733,736 bytes
the font is now the largest embedded asset in the repository.
ttf-parser is declared with default-features = false and only
"opentype-layout". Verified differentially: the ttf-parser feature set from
`cargo tree -e features` is byte-identical with and without this dependency
line, so the declaration widens nothing and forces no rebuild of the font
chain.
That check also corrected acceptance 17, which asserted `std` would be absent.
It is not — fontdb already enables it via `std = ["ttf-parser/std"]`, upstream
and independent of us. As written the criterion would have failed a correct
implementation, so it is now stated as the differential property that actually
matters.
MathConstants reads only what the Q#MS2 subset needs — axis height, script
scale percent, the two script shifts, and fraction rule thickness. Reading
more would be speculative: constants for deferred constructs have no consumer
to validate them, which is the Q#LX5 discipline applied to metrics. A font
with no MATH table is a typed error rather than plausible-looking zeros, so a
bundled-font regression cannot be silent (Q#MS7).
math_italic implements TeX's convention as the framing's table states it:
ASCII letters and lowercase Greek italic, uppercase Greek upright, digits and
operators unchanged, with U+210E for `h` because the 1D4xx run has a hole
there and arithmetic would land on a reserved codepoint.
Five tests, all against the real embedded bytes rather than fixtures, since B5
is the bet that would sink Tier 3 if false. One goes beyond the framing: every
italic mapping must resolve to a glyph the bundled font actually has, because
a mapping that produced tofu would be worse than the roman fallback it
replaces.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Levi Neuwirth