@openseat/core/templates

Wheelchair places the template harness asks for: max(1, ceil(seats x 0.5%)).

An "Accessible" standing area (wheelchair places and companions) at 0.5 persons/m², category 'accessible'. places caps the capacity; when the rectangle is too small for them a note says how many fit.

A named facility drawn as a decor polygon (or an obstacle seats can never overlap, for solid furniture: bar, buffet, FOH, DJ, screen) with a label object, since polygon names are not drawn on the map.

seg + 1 points on a circular arc from a0 to a1 degrees.

count arc wedges between from and to degrees around center, separated by gangways at least gangwayM wide at the front row (the kit's arcRun). Labels: labels[i], else ${labelPrefix}${i + 1}.

Area of a polygon given in metres, in m².

A 400 m athletics track (straights east-west): the track surface, the infield (a football pitch, grass or nothing), lane lines, the finish line and the 100 m start extension west of the home (south) straight.

Banquet rounds: T60 (1.52 m, 8-10 seats) or T72 (1.83 m, 10-12 seats) on the TABLEGRID.

A dance battle: a circular or square cypher floor (a stage), the audience on 3 sides (north open), 4 sides or an arc round the south, as seated sections, standing bands or seated front rows with standing behind; the judges' table on the north side (not for sale), a DJ booth (an obstacle) and a crew holding zone (a polygon, no inventory).

Back-to-back booth pairs: blocks blocks of columnsPerBlock booths across, separated by cross aisles, and pairs pairs of rows separated by main aisles. Labels are ${row letter}${n}; the booths at each block row's ends take cornerCategory.

A plain booth grid; labels ${labelPrefix}${n} row by row; the four corners take cornerCategory.

Booths around an ellipse (inner edges touching it), rotated to face the centre. The count is lowered (with a note) until neighbours do not overlap.

Builds a template layout:

1. resolves the params (defaults, size preset, input; snapped and clamped) and, with targetCapacity, fits the capacity driver;
2. runs the setup's builder on a fresh TemplateKit;
3. creates the layout with the kit's referenced categories;
4. moves everything (objects, venue, focal point and block frames) by whole grid cells so the content starts 40 units from the canvas origin, with a plain map over positions (locked surfaces move too and sections keep their seating), sizes the canvas to the venue and objects plus 40 and calls fitCanvasToContent;
5. writes metadata.openseat (OpenSeatMeta): units, the template stamp, block stamps, not-for-sale categories and IDs and the indicative INR prices of the categories present. Block stamps are dropped, with a note, when the metadata would exceed 48 KB;
6. with zonesOnly, turns every section into a zone (zoneTemplateLayout);
7. enforces TEMPLATE_LIMITS (TemplateInputError) and summarises.

Identical input gives a byte-identical serializeLayout; no timestamps are written. setup is a registered setup id or, for tests and fixtures, a definition.

Cabaret rounds: small rounds on a staggered grid for sightlines.

An open Catmull-Rom spline through pointsM (centripetal-free, uniform), with samples segments between each pair of points. The first and last points are kept.

Problems with one param spec (and its relation to the others).

Problems with one setup definition on its own.

Every registry rule. Returns human-readable problems; empty when clean.

Clears the build memo (tests).

CIELAB chroma; 0 for a malformed colour.

CIE76 colour difference; Infinity when either colour is malformed.

CIELAB (D65) of a #rrggbb colour, or null when it is not one.

Structural columns (obstacles) on a grid inside zoneM, starting half a pitch in from its edges; columns inside skipM are left out.

A cricket ground: the oval outfield (pitch north-south), the boundary rope, the 30-yard circle, the pitch strip with creases, optional sight screens (obstacles) beyond the boundary at both ends and a pavilion (decor) on the west.

Optimal-string-alignment (restricted Damerau-Levenshtein) distance, capped at max + 1.

A dance floor (decor, or sold as standing at 1.0/m² with standing) and an optional DJ booth (an obstacle) on one side. keepOutM covers both, ready to pass to tableGrid.

Declares a setup with params typed from its ParamSpec tuple. Use as const on the params array.

The density caution text. Summaries compute the same text from GA capacities, so the two merge.

Classroom desks in runs (desksPerRun side by side, aisles between runs), students on the back edge facing frontSide. Recorded as 'desk-runs'.

The band between two concentric ellipses from a0 to a1 degrees: the outer arc forwards, then the inner arc back. An inner radius of 0 closes the sector at the centre. A full 360-degree sweep is not supported (it would not be a simple polygon); use two halves.

An end-stage standing show: the stage, a fan pit at the stage front (1.6/m², behind a security moat), a barrier line, the general standing floor (1.4/m²) wrapped round the pit as one U-shaped area with the FOH desk cut out (its area is not counted), the FOH desk itself (an obstacle) and an accessible viewing platform (0.5/m²) at the back of the floor.

A fan-shaped house: concentric bands (price bands, front to back) of arc sections, one per wedge. Each band's front row sits behind the previous band's back row (plus gapAfterM); rows continue across bands.

A param spec by key, or undefined.

Finds the driver value whose capacity best matches target, by binary search over the driver's step grid (capacity must be non-decreasing in it). Uses capacity.estimate when present, buildTemplate summaries otherwise (about 8 builds at most, memoised). A target above the max returns the max with a note; below the min returns the min with a note.

32-bit FNV-1a hash of a string.

A football pitch (default 105 x 68 m) with boxes, centre circle and penalty spots.

Planning capacity of a standing area: floor((area − deduct) × density), at least 1. boundaryUnits is in layout units (unitsPerMetre per metre).

Entrances: explicit gates, and/or north/south/east/west gates spread evenly along the walls of wallsM. Gates on the east and west walls are rotated 90 degrees. Labels continue ${labelPrefix}${n} across the walls (north, east, south, west).

A manifest setup (implemented or not) by its full id.

An implemented setup by its full id.

A hockey pitch (91.4 x 55 m): centre line, 23 m lines and shooting circles.

A rectangle grown by d on every side (normalised corners).

True when values has an entry for every param of the setup.

True for setups that get the reduced matrix: flagged heavy, or estimated above 8k seats by default.

Island stands (large booths) on a grid with aisles all round.

Joins the manifest with the implemented setup definitions. Every venue is returned; setups holds its implemented setups only, in manifest order.

Kabaddi: men 13 x 10 m, women 12 x 8 m, with baulk, bonus and lobby lines.

Implemented setups in registry order, optionally of one category.

Venues in registry order. By default venues with no implemented setup are hidden.

A row of lounge sets: a coffee table with sofa places on both long sides.

Metres to layout units, rounded to 1e-3.

A venue's aliases with the owner's names merged in centrally: the list-A names it is PRIMARY for and its list-B subtype names. Boost venues do not get the list-A name (search scores them separately).

mulberry32 PRNG: deterministic floats in [0, 1).

The row label index that follows rows rows starting at start with the kit's alpha labelling (I and O skipped), so a price band behind another continues its letters: nextRowStart(1, 3) = 4 (A-C, then D).

Normalised, stemmed tokens of a text, stop words dropped.

Named param combinations for the build matrix. Every combo is fully resolved and in range; identical combos are dropped (the first name wins).

Light setups: default, small, large, all-min, all-max, maxCapacity, minCapacity, each numeric param alone at min and at max, each enum option, each boolean flipped, and 6 seeded randoms. Heavy setups: default, small, large, maxCapacity, each param extreme with the rest at default, each enum option, and 4 seeded randoms. Randoms use mulberry32 seeded with FNV-1a of the setup id.

n evenly spaced on-grid values of an int/number param, min and max included.

Places built into target.

replace: the template's layout under the target's id and revision, with metadata = the target's other metadata plus the template's openseat block; the canvas follows the template FRAME rule (venue and objects plus 40, then fitCanvasToContent). removedInventoryIds lists every target inventory key the template does not have, for the editor's destructive-change guard.

insert (built on core's copyInto):

• object ids become ${ns}:${id}, ns the first free of t1, t2…;
• a section label that clashes (case-insensitively) with an existing one gets (2), (3)…, and its seats' public ids are re-derived from it (${label}-${row}-${seat}, the rule seats added later follow);
• other inventory keys are kept unless they clash, then become ${ns}-${key};
• categories merge by id (existing ones win); not-for-sale categories, suggested prices, not-for-sale ids and block stamps are merged with their ids remapped; the template stamp is appended to inserts (the last 20 are kept);
• the content is centred on at, or else placed right of the existing content (the arena preset rule); the target's venue and focal point stay;
• the canvas grows with fitCanvasToContent.

zonesOnly places the template's zone variant in either mode.

A pool: the deck, the water and lane ropes (long axis east-west unless vertical).

A metre point in layout units.

Ramer-Douglas-Peucker simplification of an open polyline; keeps both ends. Iterative.

A rectangle's centre, width, height and corners (clockwise from the top-left). Corners may come in any order.

A rectangle from its centre and size (metres).

Corners of a w x h rectangle centred on the origin, clockwise from the top-left.

Smallest rectangle containing every given rectangle; a zero rect at the origin for none.

Rebuilds block blockId with params (merged over the stamp's params).

The block is rebuilt in a sub-kit with the stamp's prefix and frame, translated by the drift of the surviving members' centroid (so a block the user moved regenerates where it now is). Per slot:

• an existing member keeps its object id (the inventory key of a whole-booked table), its booth inventoryId, its seats' object and seat ids (by seat number), their accessibility flags and its label (labels only follow the new numbering when a label param changed and the user had not renamed the member); its category and bookAsWhole follow the new params unless the user had changed them;
• a member the user deleted is recreated (under its old id when free);
• a slot that no longer exists is removed with its seats and reported in removedInventoryIds (also when a kept table loses seats). New members get labels that do not clash with kept ones. The stamp (params, frame and slots) and metadata.openseat.notForSale are updated, and vocab categories the new members use are added. An unknown block id returns the layout unchanged.

Resolves the params of a build: defaults, then the size preset, then input. Numbers are snapped to their step, then clamped; a bad type or enum value falls back to the default with an issue; unknown keys are dropped. Never throws.

Rounds to 3 decimals, without -0.

A runway show: the main stage (north) with a ramp running south from its front centre, drawn as one thrust stage (with a T crossbar at the head when shape is "T"), the audience on both sides of the ramp (seated sections facing it, with optional front price rows, or standing bands), a press photo pit at the ramp head (not for sale), the judges' table beyond it (not for sale) and a backstage zone (a polygon, no inventory) behind the stage.

The schematic as a standalone SVG string. Presentation attributes only (fill, stroke, stroke-width, fill-opacity): no style attributes or elements, so it renders under a strict Content-Security-Policy.

Searches venue templates. Pure and deterministic. An empty query lists every venue in registry order (score 0). facet keeps venues with at least one setup of that facet and scores only those setups.

Problems with a set of sellable category colours: missing, malformed, near-grey, or too close to another sellable colour. Empty when fine.

Snaps to the spec's step grid, THEN clamps to [min, max]; ints are rounded.

A stand of count identical block sections side by side, facing the line through focus from side (convention C4: row A nearest the line, seat 1 at the spectator's left). Labels run left to right from the spectator's view: labels[i], else ${labelPrefix}${i + 1}.

Light plural stemming: ies -> y, (s|x|z|ch|sh)es -> drop es, s -> drop s.

Counts for the template gallery and the build summary, derived from the objects alone, so they also work on a layout the user has edited:

• seats: every seat object, table seats included; tableSeats: seats owned by a table.
• Not for sale: seats, GA places and whole tables in a category listed in metadata.openseat.unsellableCategories (the vocabulary's not-for-sale categories when the layout lists none), or covered by metadata.openseat.notForSale (unsellableInventory). unsellableSeats counts those seats; totalCapacity is the sellable seats plus the sellable GA capacity (booths are not people).
• Zone sections (showSeats: false) sell their capacity instead of their seats: totalCapacity counts the capacity of each one that is for sale, and unsellableSeats the seats beyond it (all of them when the zone is held back). Seats, tables, accessible places and the per-category seat counts still count the seats kept in the document, so a setup's seat and zone variants report the same figures. zones counts zone sections plus GA areas.
• accessible: wheelchair seats plus the capacity of GA areas in the "accessible" category.
• cautions: GA areas planned above 1.5 persons/m² and layouts above TEMPLATE_LIMITS.largeLayoutWarn seats. notes is empty here; buildTemplate adds the kit's clamp notes.

Reads measure from a build summary.

The TABLEGRID algorithm (see the module comment) over zoneM, recorded as a 'table-grid' block. Pitches are raised (with a note) so neighbouring footprints never touch; count is capped at the free cells.

Team tables (hackathons, LAN parties): rect tables with seats on both long sides. Recorded as 'team-tables'.

The schematic of layout in a width x height viewBox (default 320 x 200), fitted with a 4-unit margin. roles (BuiltTemplate.roles) tells surfaces, markings, zones and obstacles apart; without it polygon zIndex decides. At most SCHEMATIC_MAX_BYTES serialised.

A theatre house: columns (left to right from the audience) times tiers (price bands, front to back), each a separate block section. Rows continue across tiers (VIP A-C, Gold D-P…); a cross aisle may separate tiers. Wheelchair places go in the front row of the first tier, sized for each column's seats in every tier.

A point rounded to 1e-3.

Layout units to metres, rounded to 1e-3.

A rectangle with a rectangular notch cut into one of its edges (a U shape), e.g. a standing area wrapped around a front-of-house desk. The notch is clipped to the outer rectangle and cut from the edge it is nearest to. A notch that does not overlap the outer rectangle, or that would split it, leaves the plain rectangle.

True when value is a valid, in-range, on-grid value of spec.

The vocab entry for an id, or undefined for ids outside the vocab.

The zone variant of a built template layout:

1. core toZoneOnlyLayout: loose rows, tables and seats are wrapped into sections, and every section with seats becomes a zone section;
2. each zone section sells what its seats sold: its capacity defaults to its seat count, and becomes the number of its sellable seats when some were not for sale; a section with no sellable seat is listed in metadata.openseat.notForSale (unless its category already holds it back), and a section held back only by its category while some of its seats sold takes their most common sellable category instead;
3. zone sections get rounded corners (ZONE_CORNER_RADIUS_M); the sections core added are rounded to 1e-3 like every template coordinate;
4. when every zone is seated (no standing GA), the footnote ZONES_SEATED_FOOTNOTE is centred under the content (core createFootnote, sized to the content width), and the canvas grows to fit it;
5. the template stamp records zonesOnly: true.

Seats themselves are never changed, so the sellable capacity equals the seat variant's. A layout that is already a zone layout is returned as is.

Thrown for out-of-range input that cannot be clamped (unknown setup, limits).