Rstudio shiny ggvis tooltip on mouse hover

Question

In the example below, I have an interactive shiny ggvis plot, but I added a long column that is a long string and for some reason, my hover pop-up shows wt and mpg but does not show long.

Also, if the list of elements in the legend is too long, they are hidden at the bottom right corner of the plot. Is there any way to stack these in several columns in the legend?

Any ideas?

# ui.R
library(ggvis)
shinyUI(pageWithSidebar(
  div(),
  sidebarPanel(
    sliderInput("n", "Number of points", min = 1, max = nrow(mtcars),
                value = 10, step = 1),
    uiOutput("plot_ui")
  ),
  mainPanel(
    ggvisOutput("plot"),
    tableOutput("mtc_table")
  )
))


# server.R
library(shiny)
library(ggvis)
shinyServer(function(input, output, session) {
  # A reactive subset of mtcars
  mtc <- reactive({
      data = mtcars[1:input$n, ]
      data$long = as.character(paste0("A car with ",data$cyl," cylinders and ",data$gear," gears and ",data$carb, " carburators"))
      data
  })
  # A simple visualisation. In shiny apps, need to register observers
  # and tell shiny where to put the controls
  mtc %>%
    ggvis(~wt, ~mpg) %>%
    layer_points(fill = ~factor(long)) %>%
    add_tooltip(function(data){paste0("Wt: ", data$wt, "<br>", "Mpg: ",as.character(data$mpg), "<br>", "String: ", as.character(data$long))}, "hover") %>%
    bind_shiny("plot", "plot_ui")

   output$mtc_table <- renderTable({
     mtc()[, c("wt", "mpg", "long")]
   })
})

Answer 1

You need to add long as a key currently data$long is null in the anonymous function supplied to add_tooltip:

library(shiny)
library(ggvis)

runApp(list(ui = pageWithSidebar(
  div(),
  sidebarPanel(
    sliderInput("n", "Number of points", min = 1, max = nrow(mtcars),
                value = 10, step = 1),
    uiOutput("plot_ui")
  ),
  mainPanel(
    ggvisOutput("plot"),
    tableOutput("mtc_table")
  )
)
, server= function(input, output, session) {
  # A reactive subset of mtcars
  mtc <- reactive({
    data = mtcars[1:input$n, ]
    data$long = as.character(paste0("A car with ",data$cyl," cylinders and ",data$gear," gears and ",data$carb, " carburators"))
    data
  })
  # A simple visualisation. In shiny apps, need to register observers
  # and tell shiny where to put the controls
  mtc %>%
    ggvis(~wt, ~mpg, key:= ~long) %>%
    layer_points(fill = ~factor(long)) %>%
    add_tooltip(function(data){
      paste0("Wt: ", data$wt, "<br>", "Mpg: ",as.character(data$mpg), "<br>", "String: ", as.character(data$long))
    }, "hover") %>%
    bind_shiny("plot", "plot_ui")

  output$mtc_table <- renderTable({
    mtc()[, c("wt", "mpg", "long")]
  })
})
)