std.typeset.lineBadness

Public measurement fields use Length<Pt>. Widths, advances, tracking, stretch, shrink, physical targets, insets, font sizes, and optional width limits keep that type across input and output records. Explicit Length conversion functions remain the integer interchange boundary.

Box.width, Box.trackingAfter, Glue.width, Glue.trackingAfter, Glue.stretch, Glue.shrink, and Penalty.width have type Length<Pt>.

BreakCluster.advance, BreakCluster.trackingAfter, BreakPolicy.narrowestWordTarget, and BreakPolicy.bodyWordTarget have type Length<Pt>.

LatinSpacing.fontSizePt, JustificationPolicy.maxAdjustment, and JustificationPolicy.maxGapAdjustment have type Length<Pt>.

LineGeometry.bodyTarget, LineGeometry.firstTarget, and LineGeometry.dropCapInset have type Length<Pt>.

PlanLine.target, PlanLine.rawTextWidth, PlanLine.trimmedTextWidth, PlanLine.costTextWidth, and PlanLine.selectedPenaltyWidth have type Length<Pt>. PlanLine.postValidationWidthLimit has type Option<Length<Pt>>.

An int, a float, or a Length with another unit marker is not an implicit point-length argument. Convert physical units explicitly with toPt() before constructing a typesetting record.

Indices, counts, penalties, costs, and dimensionless ratios retain their declared types. LatinSpacing.maxLetterSpacingEm is a relative Length<Em>. Resolve it to Length<Pt> with fontSizePt before selecting the computation grid.

Paragraph.grid selects quantization at the computation boundary. ScaledPoint uses the exact scaled-point integer. MilliPoint uses the existing nearest-even conversion to millipoints. The selected grid never changes the physical interpretation of a public Length<Pt> value.

Returned distances are converted from the computation grid into Length<Pt> at the output boundary. ParagraphPlan.grid reports the computation policy and is not needed to interpret its distances.

The public type change preserves the selected cost model. FixedPoint retains its MilliPoint computation requirement. Word-space and CJK ratio calculations keep their independent floor rules. The relative letter-spacing distance is resolved and quantized through the shared Length conversions before it contributes to capacity.

The public line-badness entry point also receives width, target, and hyphen advance as Length<Pt>. It converts those distances to millipoints at entry and preserves its existing integer cost calculation.

lineBadness(width: Length<Pt>, target: Length<Pt>, charCount: int, spaces: int, kind: BreakKind, isLast: bool, justificationB: int, hyphenAdvance: Length<Pt>) -> Result<int, TypesetError> is the public entry point. lineBadnessMpt is absent and importing it is rejected with TPZ3009.

The three distances require Length<Pt>. A raw scalar or another unit marker is rejected with TPZ5001. Width and hyphen advance may be negative. justificationB accepts every int and can make the resulting cost negative.

Evaluate all eight argument expressions once in source order before entering the function. Convert width, target, and hyphenAdvance to millipoints in that order with the shared nearest-even rule.

The converted target must be positive. charCount and spaces must each be nonnegative and need not satisfy a relation to each other. Invalid inputs return Err containing TypesetError.InvalidInput before cost arithmetic. The explanatory message text is not fixed.

Let w, t, and h be the converted distances, c the character count, s the space count, and j the supplied justification cost. Let B be 1,000,000 and R be 100,000,000.

For a nonnegative n and positive d, H gives n divided by d rounded to the nearest integer with ties upward. H describes cost rounding. Physical Length conversion keeps its separate nearest-even rule.

The following sequence uses checked int operations in the stated order. A failing intermediate operation stops with runtime diagnostic TPZ4004. It does not return TypesetError or replace overflow with a bounded cost.

Set effective to w + h for LatinSoftHyphen and to w for every other kind. Set slack to t - effective and absolute to the absolute value of slack.

Set raw to 4 R when absolute is at least 4 t. Otherwise set raw to absolute * R / t with integer division. This explicit ratio cap does not change a supplied length.

Set capacity to 100 + s * 45 when slack is nonnegative and to 100 + s * 25 otherwise. Set ratio = H(raw * 100, capacity), then q = H(ratio * ratio, R), then cost = H(q * (1000 * B), R).

If isLast is true, replace cost with H(cost * 2, 5). Add 500 B when isLast is true and `w 100 < t * 52`. The strict comparison uses the original converted width and also applies when charCount is zero.

If slack is negative, add 20000 * B + H(20000 * B * ratio, R). Add 65 B for LatinHyphen or LatinSoftHyphen. Add 50000 B for HardFallback. The other break kinds add no break penalty.

If c is at most two, add 275 B. Then add 10 B and j in that order and return the result in Ok. The hyphenAdvance input affects width for LatinSoftHyphen and is ignored for the other kinds.

An exact fit with more than two characters, no special break penalty, and zero justification cost returns 10000000. The documented 90 point line against a 100 point target with nine characters and two spaces returns 12770080.

The function performs no I/O, changes no input, and reads no font, paragraph, or global grid state. Effects from argument evaluation remain visible on InvalidInput or a later arithmetic fault.

An arithmetic fault identifies the public lineBadness call as its primary source location. Argument effects already performed remain visible and later expressions do not run.