Add labels to an echarts map — box_labels

Pipe-able function that injects series-level label configuration into an existing echarts widget, labelling the rectangles drawn for islands = "box". Uses a JavaScript formatter that shows the geopt_label text for those rectangles and an empty string for every other feature.

Usage

box_labels_echarts(
  e,
  sf_obj,
  font_size = 12,
  color = "#333",
  position = "right",
  offset = c(92, 0),
  ...
)

Arguments

e: An echarts widget created by echarts4r::e_charts().
sf_obj: An sf object returned by get_map(). Features are matched by its name column (the one the widget was built with), or by geopt_label if there is none.
font_size: Font size for labels. Default 12.
color: Color for labels. Default "#333".
position: Label position relative to the feature bounding box. Default "right". See echarts label position options.
offset: Numeric vector of length 2 (c(x, y)) to shift the label in pixels. Default c(92, 0).
...: Additional echarts label properties (e.g. align, verticalAlign, fontWeight, rotate).

Value

The modified echarts widget.

Examples

m <- get_map("nuts3", islands = "box")
m$name <- dplyr::coalesce(m$geopt_label, m$nuts3)
geojson <- geojsonsf::sf_geojson(m)

m |>
  echarts4r::e_charts(name) |>
  echarts4r::e_map_register("pt", geojson) |>
  echarts4r::e_map(area_ha, map = "pt", roam = TRUE) |>
  box_labels_echarts(m) |>
  echarts4r::e_visual_map(area_ha)