leaflet.multiopacity (version 0.1.1)

addOpacityControls: Add Opacity Controls

Description

Add opacity controls to leaflet map. It is possible to choose which layers will have an opacity slider control by passing one of the arguments "category", "group" or "layerId" (passing more than one of these arguments will cause the others to be ignored). It is possible to pass one or more of each layerIds, categories or groups. If you leave these arguments with the default value (NULL), the opacity controls will be created to every layer in the map.

Usage

addOpacityControls(
  map,
  layerId = NULL,
  category = NULL,
  group = NULL,
  collapsed = FALSE,
  size = c("m", "s"),
  position = c("topright", "topleft", "bottomright", "bottomleft"),
  title = NULL,
  renderOnLayerAdd = FALSE
)

Arguments

map

The map to add the opacity controls to.

layerId

One or more layer IDs to render opacity controls to.

category

One or more categories to render opacity controls to. Tested categories are "tile" (base layers), "image" (e.g. raster) and "marker".

group

One or more groups to render opacity controls to.

collapsed

If FALSE (the default), the opacity control will always appear in its expanded state. Set to TRUE to have the opacity control rendered as an icon that expands when hovered over.

size

Collapsed control size: "m" (medium) or "s" (small).

position

Position of control: "topleft", "topright", "bottomleft", or "bottomright".

title

The control title.

renderOnLayerAdd

When this argument is TRUE, the controls will only appear when a new layer is added and rendered in the map. This can be useful if you plan to use 'leafletProxy()' and need the controls to be dinamically updated.

Examples

# NOT RUN {
# Load libraries
library(leaflet)
library(leaflet.multiopacity)
library(raster)

# Create raster example
r <- raster(xmn = -2.8, xmx = -2.79,
            ymn = 54.04, ymx = 54.05,
            nrows = 30, ncols = 30)
values(r) <- matrix(1:900, nrow(r), ncol(r), byrow = TRUE)
crs(r) <- crs("+init=epsg:4326")

# Provide layerId, group or category to show opacity controls
# If not specified, will render controls for all layers
# Example using layerId
leaflet() %>%
  addProviderTiles("Wikimedia", layerId = "Wikimedia") %>%
  addRasterImage(r, layerId = "raster") %>%
  addAwesomeMarkers(lng = -2.79545, lat = 54.04321,
                    layerId = "hospital", label = "Hospital") %>%
  addOpacityControls(layerId = c("raster", "hospital"))

# Example using category
leaflet() %>%
  addProviderTiles("Wikimedia", layerId = "Wikimedia") %>%
  addRasterImage(r, layerId = "raster") %>%
  addAwesomeMarkers(lng = -2.79545, lat = 54.04321,
                    layerId = "hospital", label = "Hospital") %>%
  addOpacityControls(category = c("image", "marker"))

# }