R/methods.R

In crazycapivara/openlayers: An R Interface to 'OpenLayers'

## TODO: obsolete, because stamen tiles can be added via 'add_stamen_tiles'
## only useful, because 'https' layers sometimes do not show up in RStudio
get_stamen_xyz_url <- function(layer = "toner") {
  sprintf("http://{a-c}.tile.stamen.com/%s/{z}/{x}/{y}.png", layer)
}

#' Get cartodb xyz url
#'
#' for available layers please
#' check \href{https://carto.com/location-data-services/basemaps/}{cartodb-basemaps}
#'
#' @param layer cartodb layer name
#'
#' @return cartodb xyz url for given layer
#'
#' @export
get_cartodb_xyz_url <- function(layer = "dark_all") { # nocov start
  sprintf("https://cartodb-basemaps-{a-c}.global.ssl.fastly.net/%s/{z}/{x}/{y}.png", layer)
} # nocov end

#' Cartodb attribution
#'
#' @export
cartodb_attribution <- function() { # nocov start
  c('&copy; <a href="http://www.openstreetmap.org/copyright">OpenStreetMap</a>, ',
    '&copy; <a href="https://carto.com/attribution">CARTO</a>')
} # nocov end

add_cartodb_tiles <- function(ol, layer) {
  stop("needs to be implemented, just do it")
}

#' Set the view of the map (geographical center and zoom)
#'
#' @param ol map widget
#' @param lon longitude of center
#' @param lat latitude of center
#' @param zoom zoom level
#'
#' @export
set_view <- function(ol, lon = 9.5, lat = 51.31667, zoom = 4) {
  invoke_method(ol, "setView", lon, lat, zoom)
}

#' Add tile layers to the map
#'
#' @name add_tiles
#'
#' @param ol map widget
NULL

#' @describeIn add_tiles Add osm tile layer to the map
#'
#' @export
add_osm_tiles <- function(ol, options = layer_options()) {
  invoke_method(ol, "addOSMTiles", camel_case_keys(options))
}

#' @describeIn add_tiles Add stamen tile layer to the map
#'
#' @param layer stamen layer name
#'
#' @export
add_stamen_tiles <- function(ol, layer = "watercolor", options = layer_options()) {
  invoke_method(ol, "addStamenTiles", layer, camel_case_keys(options))
}

#' @describeIn add_tiles Add custom tile layer to the map
#'
#' @param xyz_url xyz url
#' @param attribution attribution (character vector)
#' @param options layer options
#'
#' @examples \dontrun{
#'   xyz_url <- get_cartodb_xyz_url()
#'   attribution <- cartodb_attribution()
#'
#'   ol() %>%
#'     add_xyz_tiles(xyz_url, attribution)
#' }
#'
#' @export
add_xyz_tiles <- function(ol, xyz_url, attribution = NULL, options = layer_options()) {
  invoke_method(ol, "addXYZTiles", xyz_url, attribution, camel_case_keys(options))
}

# TODO: useful ? export : remove
add_geojson_ds <- function(ol, url) {
  invoke_method(ol, "addGeojsonFromUrl", url)
}

#' Add vector layer to the map
#'
#' @param ol map widget
#' @param data geojson, ignored if \code{filename} is given
#' @param filename filename or url to read geojson from
#' @param style style object or \code{NULL} (use default style)
#' @param popup popup texts
#' @param options general layer options, see \code{\link{layer_options}}
#'
#' @examples \dontrun{
#'   require("geojsonio")
#'
#'   geojson <- geojson_json(us_cities[1:10, ])
#'
#'   ol() %>%
#'     add_geojson(geojson)
#' }
#'
#' @export
add_geojson <- function(ol, data = NULL, filename = NULL, style = NULL,
                        popup = NULL, options = layer_options()) {
  if(!is.null(filename)) {
    data <- readr::read_file(filename)
  }
  invoke_method(ol, "addGeojson", data, style, popup, camel_case_keys(options))
}

require_namespace <- function(name) {
  if(!requireNamespace(name, quietly = TRUE)) {
    stop(sprintf("please install %s\n", name), call. = FALSE)
  }
}

#' Add vector layer to the map
#'
#' This function is just a shorthand to \code{\link{add_geojson}} using
#' \pkg{geojsonio} to convert any data object to geojson.
#' Therefore, if the library/namespace is not available, an error is thrown.
#'
#' @param ol map widget
#' @param data any data object which can be parsed to geojson by
#'   \code{\link[geojsonio]{geojson_json}}
#' @param ... optional parameters passed to \code{\link{add_geojson}}
#'
#' @name add_features
#'
#' @export
add_features <- function(ol, data, ...) {
  require_namespace("geojsonio")
  data <- geojsonio::geojson_json(data)
  add_geojson(ol, data, ...)
}

#' @rdname add_features
#'
#' @export
add_vector_data <- function(ol, data, ...) { # nocov start
  .Deprecated("add_features")
  add_features(ol, data, ...)
} # nocov end