R/maplibre.R

In mapgl: Interactive Maps with 'Mapbox GL JS' and 'MapLibre GL JS'

#' Initialize a Maplibre GL Map
#'
#' @param style The style JSON to use.
#' @param center A numeric vector of length 2 specifying the initial center of the map.
#' @param zoom The initial zoom level of the map.
#' @param bearing The initial bearing (rotation) of the map, in degrees.
#' @param pitch The initial pitch (tilt) of the map, in degrees.
#' @param bounds An sf object or bounding box to fit the map to.
#' @param width The width of the output htmlwidget.
#' @param height The height of the output htmlwidget.
#' @param ... Additional named parameters to be passed to the Mapbox GL map.
#'
#' @return An HTML widget for a Mapbox map.
#' @export
#'
#' @examples
#' \dontrun{
#' maplibre()
#' }
maplibre <- function(style = carto_style("voyager"),
                     center = c(0, 0),
                     zoom = 0,
                     bearing = 0,
                     pitch = 0,
                     bounds = NULL,
                     width = "100%",
                     height = NULL,
                     ...) {

  additional_params <- list(...)

  if (!is.null(bounds)) {
    if (inherits(bounds, "sf")) {
      bounds <- as.vector(sf::st_bbox(sf::st_transform(bounds, 4326)))
    }
    additional_params$bounds <- bounds
  }

  control_css <- htmltools::htmlDependency(
    name = "layers-control",
    version = "1.0.0",
    src = c(file = system.file("htmlwidgets/styles", package = "mapgl")),
    stylesheet = "layers-control.css"
  )

  htmlwidgets::createWidget(
    name = "maplibregl",
    x = list(
      style = style,
      center = center,
      zoom = zoom,
      bearing = bearing,
      pitch = pitch,
      additional_params = additional_params
    ),
    width = width,
    height = height,
    package = "mapgl",
    dependencies = list(control_css),
    sizingPolicy = htmlwidgets::sizingPolicy(
      viewer.suppress = FALSE,
      browser.fill = TRUE,
      viewer.fill = TRUE,
      knitr.figure = TRUE,
      padding = 0,
      knitr.defaultHeight = "500px",
      viewer.defaultHeight = "100vh",
      browser.defaultHeight = "100vh"
    )
  )
}

#' Create a Maplibre GL output element for Shiny
#'
#' @param outputId The output variable to read from
#' @param width The width of the element
#' @param height The height of the element
#'
#' @return A Maplibre GL output element for use in a Shiny UI
#' @export
maplibreOutput <- function(outputId, width = "100%", height = "400px") {
  htmlwidgets::shinyWidgetOutput(outputId, "maplibregl", width, height, package = "mapgl")
}

#' Render a Maplibre GL output element in Shiny
#'
#' @param expr An expression that generates a Maplibre GL map
#' @param env The environment in which to evaluate `expr`
#' @param quoted Is `expr` a quoted expression
#'
#' @return A rendered Maplibre GL map for use in a Shiny server
#' @export
renderMaplibre <- function(expr, env = parent.frame(), quoted = FALSE) {
  if (!quoted) { expr <- substitute(expr) } # force quoted
  htmlwidgets::shinyRenderWidget(expr, maplibreOutput, env, quoted = TRUE)
}