TimelineTicks.h header

enum class TimelineTickUnit { Minute, Hour, Day, Month, Year }

The unit a timeline's ruler is stepping in at the current zoom. Coarsening from Minute to Year as the view widens is what TL-15 means by an adaptive ruler.

std::vector< bool > ew::app::keepNonOverlappingLabels(const std::vector< RulerLabel > &labels, int minGap)

Given labels in ascending left-edge order (the natural ruler / elision-break draw order), returns for each whether to draw it so that no two KEPT labels come within minGap pixels of each other – a leftmost-wins sweep. This is meant to run on the FINAL pixel positions, after any axis elision has compressed the view, so labels never overprint at any zoom – including where a collapsed void squeezes many gradations (or many "N years hidden" break markers) together, the crowding TL-15's real-space tick spacing cannot foresee and TL-26 forbids. Pure geometry: the panel draws only the labels this keeps. minGap below zero is treated as zero.

TimelineRuler ew::app::timelineRuler(const ew::core::Calendar &calendar, qint64 viewStart, qint64 viewEnd, int viewportWidth, const TimelineLabelWidths &labelWidths)

Builds the ruler for the span [viewStart, viewEnd) drawn across viewportWidth pixels, in calendar, giving every gradation at least the room labelWidths says its unit needs.

Every gradation lands on a round value in the project's own calendar – the first of a month, midnight, a year divisible by the step – chosen from a 1/2/5 ladder that coarsens Minute → Hour → Day → Month → Year as the view widens.

A rung is used only if its gradations and its major band's gradations are far enough apart to fit their own labels. Testing both bands is not belt-and-braces: sizing only the minor band picks Hour/12 for an eleven-day view on a 1092px dock – twenty-two perfectly legible "00:00"s – and then hands the major band eleven "25 Harvestmoon" labels, 168px each, into 99px slots. That trades a thin ruler for a smeared one. A rung is admissible only if the whole ruler it implies is legible.

This exists because the old ruler was the visible span cut into four equal pieces (kAxisTicks = 5), whatever those happened to land on: it produced gradations like "1 Highsun, Year 1206 AC, 18:00" – not round, not adaptive, single-tier, and carrying a time of day on a view spanning ninety years (docs/TIMELINE_AUDIT.md TA-3). Note that the stray "18:00" was Calendar::format behaving correctly on a non-midnight instant; picking round instants removes it at the source, because a date at midnight formats without a time.

Each band's count is bounded by viewportWidth divided by that band's own label width, so no zoom – however absurd – can ask for a runaway number of ticks.

QString ew::app::widestContextSample(const ew::core::Calendar &calendar, TimelineTickUnit minorUnit)

The widest context label that can appear above a minorUnit ruler in calendar – what that unit's own labels leave out. Empty for Year, which has no context band (see TimelineRuler::major).

QString ew::app::widestLabelSample(const ew::core::Calendar &calendar, TimelineTickUnit unit)

The widest label unit can emit for calendar – a sample string, for the caller to measure.

This lives beside the code that formats the labels because it is the same knowledge: a Day gradation reads "25", so its widest case is a two-digit day. Month names are project data – a conlang month can be far longer than any English one – so no compile-time guess is safe, and only the caller can measure a font. Keeping the sample next to timelineRuler's own labelling is what stops the two drifting apart, which is exactly how a ruler starts reserving room for the wrong string.