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Create a dragmapr state object

Source: R/state.R
dragmapr_state.Rd

A dragmapr_state stores the mutable, editorial layout of a draggable map separately from the source geometry and from display options. It is the shared composition contract handed between layout producers (such as explodemap::as_dragmapr_state()), the interactive editor, and static renderers.

Usage

dragmapr_state(
  level = "region",
  region_offsets = NULL,
  label_offsets = NULL,
  expanded_groups = character(),
  view = NULL,
  version = 0L,
  crs = NULL,
  geometry_id = NULL,
  selected_feature = NULL
)

Arguments

level

Character label for the active geography level.

region_offsets

Data frame with region, dx_m, and dy_m.

label_offsets

Data frame with label_id, region, dx_m, and dy_m.

expanded_groups

Character vector of expanded parent groups.

view

Optional list describing the client view, such as scale and translation.

version

Integer state revision.

crs

Optional coordinate reference system the metre offsets are expressed in. Accepts anything sf::st_crs() understands (an EPSG code, a PROJ/WKT string, or a crs object). Stored as an EPSG integer when available, otherwise as a WKT string, so it round-trips through JSON. Because dx_m/dy_m are only meaningful in a projected CRS, recording it here makes a saved state safe to reapply in a later session.

geometry_id

Optional single string identifying the geometry this state was composed against (provenance / binding tag). Lets a downstream consumer detect when a state is being applied to a different dataset than it was authored for.

selected_feature

Optional single string naming the feature currently selected in a dashboard or editor. Carried so a composition can be restored with focus intact.

Value

An object of class "dragmapr_state".

Details

The state is deliberately geometry-free: it carries deltas, not absolute geometry, and is bound to features at apply time via a join key. That key is the region column of the offset tables. For durable round-trips prefer a stable code (e.g. a FIPS/ISO id) over a display name, and record which geometry the state was composed against with geometry_id.