add and clear legend

DESCRIPTION

@@ -27,7 +27,7 @@ Imports:
     Rcpp (>= 1.0.10),
     shiny,
     sfheaders (>= 0.4.4)
-RoxygenNote: 7.2.3
+RoxygenNote: 7.3.1
 LinkingTo: 
     BH,
     colourvalues (>= 0.3.9),

NAMESPACE

@@ -58,6 +58,7 @@ export(add_h3)
 export(add_heatmap)
 export(add_hexagon)
 export(add_i3s)
+export(add_legend)
 export(add_line)
 export(add_mesh)
 export(add_path)

NEWS.md

@@ -1,5 +1,6 @@
 # v0.3.6
 
+* `add_legend` and `clear_legend()` for adding custom legends to the map [issue 390](https://github.com/SymbolixAU/mapdeck/issues/390)
 * `add_text()` gets `elevation` argument for when using a `data.frame`
 * `map_click` event added to shiny - e.g. `observeEvent({input$map_click})`
 

R/map_legend.R

@@ -0,0 +1,83 @@
+
+#' Add Legend
+#'
+#' Add a custom legend to the map
+#'
+#' @inheritParams add_scatterplot
+#'
+#' @examples
+#'
+#' \donttest{
+#' sf <- spatialwidget::widget_melbourne
+#' sf$my_colour <- ifelse( substr(sf$SA2_NAME, 1, 1) == "A", "#00FF00FF", "#FF0000FF")
+#'
+#' l1 <- legend_element(
+#' 	variables = c("Begins with A", "Doesn't begin with A")
+#' 	, colours = c("#00FF00FF", "#FF0000FF")
+#' 	, colour_type = "fill"
+#' 	, variable_type = "category"
+#' )
+#' js <- mapdeck_legend(l1)
+#'
+#' set_token(secret::get_secret("MAPBOX"))
+#' mapdeck() %>%
+#'   add_legend(legend = js, layer_id = "my_layer")
+#'
+#'
+#'mapdeck() %>%
+#'   add_legend(legend = js, layer_id = "my_layer") %>%
+#'   clear_legend(layer_id = "my_layer")
+#'
+#' }
+#'
+#' @export
+add_legend <- function(map, legend, layer_id) {
+
+	legend_format <- "hex"
+
+	invoke_method(
+		map, "md_add_legend", map_type(map), layer_id, legend, legend_format
+	)
+}
+
+
+#' Clear Legend
+#'
+#' Removes a legend from the map
+#'
+#' @inheritParams add_legend
+#'
+#' @examples
+#' \donttest{
+#'
+#' sf <- spatialwidget::widget_melbourne
+#' sf$my_colour <- ifelse( substr(sf$SA2_NAME, 1, 1) == "A", "#00FF00FF", "#FF0000FF")
+#'
+#' l1 <- legend_element(
+#' 	variables = c("Begins with A", "Doesn't begin with A")
+#' 	, colours = c("#00FF00FF", "#FF0000FF")
+#' 	, colour_type = "fill"
+#' 	, variable_type = "category"
+#' )
+#' js <- mapdeck_legend(l1)
+#'
+#' set_token(secret::get_secret("MAPBOX"))
+#'
+#' ## Add a legend
+#' mapdeck() %>%
+#'   add_legend(legend = js, layer_id = "my_layer")
+#'
+#' ## Calling `clear_legend` should immediately remove it
+#' mapdeck() %>%
+#'   add_legend(legend = js, layer_id = "my_layer") %>%
+#'   clear_legend(layer_id = "my_layer")
+#'
+#' }
+#'
+#' @export
+clear_legend <- function(map, layer_id) {
+
+	invoke_method(
+		map, "md_clear_legend", map_type(map), layer_id
+	)
+}