Remove zoom controls from rendered leaflet map in Shiny

Question

Leaflet provides an option, when setting up your map, to hide the zoom controls

leaflet(options = leafletOptions(zoomControl = FALSE)

However, I would like to call this option after having already created a map so that a user can download the map without the zoom controls and without me having to re-create a different version of the map from scratch.

Here's a simple version of my app at the moment:

library(shiny)
library(tidyverse)
library(leaflet)
library(mapview)

ui <- fluidPage(
  fluidPage(
    leafletOutput(outputId = "map"),
    downloadButton(outputId = "save")
  )
)

server <- function(input, output, session) {

  map <- reactive({
    leaflet() %>%
      addTiles()
  })

  output$map <- renderLeaflet({
    map()
  })

  output$save <- downloadHandler(
    filename = "map.jpeg",
    content = function(file){
      latRng <- range(input$map_bounds$north,
                      input$map_bounds$south)
      lngRng <- range(input$map_bounds$east,
                      input$map_bounds$west)
      map() %>%
        setView(lng = (lngRng[1] + lngRng[2])/2,
                lat = (latRng[1] + latRng[1])/2,
                zoom = input$map_zoom) %>%
        ### HERE ###
        mapshot(file = file)
    }
  )

}

shinyApp(ui, server)

I'd like to be able to add a line of code where I've commented ### HERE ### that would turn off zoom controls. In my actual code the displayed map is really complex with lots of options and I wouldn't want to have all that code twice just for the sake of removing zoom controls in the initial call to leaflet().

Answer 1

You can do it like so:

library(shiny)
library(tidyverse)
library(leaflet)
library(mapview)

ui <- fluidPage(
  fluidPage(
    leafletOutput(outputId = "map"),
    downloadButton(outputId = "save")
  )
)

server <- function(input, output, session) {

  map <- reactive({
    leaflet() %>%
      addTiles()
  })

  output$map <- renderLeaflet({
    map()
  })

  output$save <- downloadHandler(
    filename = "map.jpeg",
    content = function(file){
      latRng <- range(input$map_bounds$north,
                      input$map_bounds$south)
      lngRng <- range(input$map_bounds$east,
                      input$map_bounds$west)
      m = map() %>%
        setView(lng = (lngRng[1] + lngRng[2])/2,
                lat = (latRng[1] + latRng[1])/2,
                zoom = input$map_zoom)
      m$x$options = append(m$x$options, list("zoomControl" = FALSE))
      mapshot(m, file = file)
    }
  )

}

shinyApp(ui, server)

which is updating the leaflet options after map creation. I will incorporate this in the mapshot function to optionally remove the zoomControl.