R/map_layer_polygon.R

In SymbolixAU/mapdeck: Interactive Maps Using 'Mapbox GL JS' and 'Deck.gl'

mapdeckPolygonDependency <- function() {
	list(
		createHtmlDependency(
			name = "polygon",
			version = "1.0.0",
			src = system.file("htmlwidgets/lib/polygon", package = "mapdeck"),
			script = c("polygon.js"),
			all_files = FALSE
		)
	)
}


#' Add Polygon
#'
#' The Polygon Layer renders filled and/or stroked polygons.
#'
#' @inheritParams add_arc
#' @inheritParams add_line
#'
#' @param polyline optional column of \code{data} containing the polylines, if using encoded polylines
#' @param fill_colour column of \code{data} or hex colour for the fill colour.
#' If using a hex colour, use either a single value, or a column of hex colours  on \code{data}
#' @param fill_opacity Either a string specifying the column of \code{data}
#' containing the opacity of each shape, or a single value in [0,255], or [0, 1),
#' to be applied to all the shapes. Default 255. If a hex-string is used as the
#' colour, this argument is ignored and you should include the alpha on the hex string
#' @param stroke_colour variable of \code{data} or hex colour for the stroke. If used,
#' \code{elevation} is ignored.
#' If using a hex colour, use either a single value, or a column of hex colours  on \code{data}
#' @param stroke_width width of the stroke in meters. If used, \code{elevation} is ignored. Default 1.
#' @param light_settings list of light setting parameters. See \link{light_settings}
#' @param elevation the height the polygon extrudes from the map. Only available if neither
#' \code{stroke_colour} or \code{stroke_width} are supplied. Default 0
#' @param elevation_scale elevation multiplier.
#'
#' @section data:
#'
#' If the \code{data} is a simple feature object, the geometry column is automatically
#' detected. If the sf object contains more than one geometry column and you want to use a specific one,
#' you'll need to set the active geometry using \code{sf::st_geometry( x ) <- "your_column" },
#' where \code{"your_column"} is the name of the column you're activating. See \code{?sf::st_geometry}
#'
#'
#' @inheritSection add_arc legend
#' @inheritSection add_arc id
#'
#' @section transitions:
#'
#' The transitions argument lets you specify the time it will take for the shapes to transition
#' from one state to the next. Only works in an interactive environment (Shiny)
#' and on WebGL-2 supported browsers and hardware.
#'
#' The time is in milliseconds
#'
#' Available transitions for polygon
#'
#' list(
#' polygon = 0,
#' fill_colour = 0,
#' stroke_colour = 0,
#' stroke_width = 0,
#' elevation = 0
#' )
#'
#' @examples
#' \donttest{
#'
#' ## You need a valid access token from Mapbox
#' key <- 'abc'
#' set_token( key )
#'
#' library(geojsonsf)
#'
#' sf <- geojsonsf::geojson_sf("https://symbolixau.github.io/data/geojson/SA2_2016_VIC.json")
#'
#' mapdeck(
#'   style = mapdeck_style('dark')
#' ) %>%
#'   add_polygon(
#'     data = sf
#'     , layer = "polygon_layer"
#'     , fill_colour = "SA2_NAME16"
#' )
#'
#' df <- melbourne  ## data.frame with encoded polylnies
#' df$elevation <- sample(100:5000, size = nrow(df))
#' df$info <- paste0("<b>SA2 - </b><br>",df$SA2_NAME)
#'
#' mapdeck(
#'   style = mapdeck_style('dark')
#'   , location = c(145, -38)
#'   , zoom = 8
#'   ) %>%
#'   add_polygon(
#'     data = df
#'     , polyline = "geometry"
#'     , layer = "polygon_layer"
#'     , fill_colour = "SA2_NAME"
#'     , elevation = "elevation"
#'     , tooltip = 'info'
#'     , legend = TRUE
#'   )
#'
#' }
#'
#' @details
#'
#' \code{add_polygon} supports POLYGON and MULTIPOLYGON sf objects
#'
#' @export
add_polygon <- function(
	map,
	data = get_map_data(map),
	polyline = NULL,
	stroke_colour = NULL,
	stroke_width = NULL,
	stroke_opacity = NULL,
	fill_colour = NULL,
	fill_opacity = NULL,
	elevation = NULL,
	tooltip = NULL,
	auto_highlight = FALSE,
	elevation_scale = 1,
	highlight_colour = "#AAFFFFFF",
	light_settings = list(),
	layer_id = NULL,
	id = NULL,
	palette = "viridis",
	na_colour = "#808080FF",
	legend = FALSE,
	legend_options = NULL,
	legend_format = NULL,
	update_view = TRUE,
	focus_layer = FALSE,
	digits = 6,
	transitions = NULL,
	brush_radius = NULL,
	...
) {

	if( nrow( data ) == 0 ) {
		return( clear_polygon( map, layer_id, ... ) )
	}

	l <- list()
	l[["polyline"]] <- force( polyline )
	l[["stroke_colour"]] <- force( stroke_colour )
	l[["stroke_width"]] <- force( stroke_width )
	l[["stroke_opacity"]] <- resolve_opacity( stroke_opacity )
	l[["fill_colour"]] <- force( fill_colour )
	l[["fill_opacity"]] <- resolve_opacity( fill_opacity )
	l[["elevation"]] <- force( elevation )
	l[["tooltip"]] <- force( tooltip )
	l[["id"]] <- force( id )
	l[["na_colour"]] <- force( na_colour )

	l <- resolve_palette( l, palette )
	l <- resolve_legend( l, legend )
	l <- resolve_legend_options( l, legend_options )
	l <- resolve_data( data, l, c("POLYGON") )

	bbox <- init_bbox()
	update_view <- force( update_view )
	focus_layer <- force( focus_layer )
	elevation_scale <- force( elevation_scale )

	is_extruded <- FALSE
	## issue 287
	if( !is.null( elevation ) ) {
		is_extruded <- TRUE
	}
	if( !is.null( l[["stroke_width"]] ) | !is.null( l[["stroke_colour"]] ) ) {
		is_extruded <- FALSE
		if( !is.null( elevation ) ) {
			message("stroke provided, ignoring elevation")
		}
		if( is.null( l[["stroke_width"]] ) ) {
			l[["stroke_width"]] <- 1L
		}
	}

	if ( !is.null(l[["data"]]) ) {
		data <- l[["data"]]
		l[["data"]] <- NULL
	}

	## sf objects come with a bounding box
	if( !is.null(l[["bbox"]] ) ) {
		bbox <- l[["bbox"]]
		l[["bbox"]] <- NULL
	}

	checkHexAlpha(highlight_colour)
	layer_id <- layerId(layer_id, "polygon")

	map <- addDependency(map, mapdeckPolygonDependency())

	tp <- l[["data_type"]]
	l[["data_type"]] <- NULL

	jsfunc <- "add_polygon_geo"

	if ( tp == "sf" ) {
		geometry_column <- c( "geometry" ) ## This is where we woudl also specify 'origin' or 'destination'
		shape <- rcpp_polygon_geojson( data, l, geometry_column, digits )
	} else if ( tp == "sfencoded" ) {
		geometry_column <- "polyline"
		shape <- rcpp_polygon_polyline( data, l, geometry_column )
		jsfunc <- "add_polygon_polyline"
	# } else if ( tp == "mesh" ) {
	# 	geometry_column <- "geometry"
	# 	jsfunc <- "add_mesh"
	# 	shape <- rcpp_mesh_geojson( data, l, geometry_column )
	}

	light_settings <- jsonify::to_json(light_settings, unbox = T)
	js_transitions <- resolve_transitions( transitions, "polygon" )

	if( inherits( legend, "json" ) ) {
		shape[["legend"]] <- legend
	} else {
		shape[["legend"]] <- resolve_legend_format( shape[["legend"]], legend_format )
	}

	invoke_method(
		map, jsfunc, map_type( map ), shape[["data"]], layer_id, light_settings,
		auto_highlight, highlight_colour, shape[["legend"]], bbox, update_view, focus_layer,
		js_transitions, is_extruded, elevation_scale, brush_radius
		)
}



#' @rdname clear
#' @export
clear_polygon <- function( map, layer_id = NULL, update_view = TRUE, clear_legend = TRUE) {
	layer_id <- layerId(layer_id, "polygon")
	invoke_method(map, "md_layer_clear", map_type( map ), layer_id, "polygon", update_view, clear_legend )
}