添加suspendWhenHidden时，quartz()设备大小无效

Question

I have an app such that after a user has selected input in tab 1, the app will redirect the user to tab 2, where a plot is generated based on the input selected in tab 1. I added suspendWhenHidden = FALSE so that the plot will be generated before the user is redirected to tab 2. However, when I added the following line of code, outputOptions(output, "mtcarsplot", suspendWhenHidden = FALSE) , the console shows a warning.

Can anyone explain/solve the error in the code? Thanks for the help. I have added the code and then the warning message below.

the app's code (MWE):

data(mtcars)

ui <- fluidPage(
  navbarPage(title = "Plotting", id = "mtcars",
             tabPanel(title = "home",
                      selectInput(inputId = "col", label = "Choose a column", choices = names(mtcars)),
                      actionButton(inputId = "update", label = "Update")
             ),
             tabPanel(title = "plot",
                      plotOutput("mtcarsplot"), 
                      actionButton(inputId = "back", label = "Back")
             ))
)

server <- function(input, output, session) {
  observeEvent(input$update, {
    updateTabsetPanel(session = session, inputId = "mtcars", selected = "plot")
  })
  
  col <- eventReactive(input$update, {
    input$col
  })
  
  observeEvent(input$back, {
    updateTabsetPanel(session = session, inputId = "mtcars", selected = "home")
  })
  
  mtcars_new <- reactive({
    mtcars %>%
      select(mpg, userscol = col())
  })
  
  mtcars_plot <- reactive({
    ggplot(data = mtcars_new(), aes(x = mpg, y = userscol)) +
      geom_point()
  })
  
  output$mtcarsplot <- renderPlot({mtcars_plot()})
  outputOptions(output, "mtcarsplot", suspendWhenHidden = FALSE)
}


shinyApp(ui = ui, server = server)

The Warning message:

Warning: Error in <Anonymous>: invalid quartz() device size
  128: <Anonymous>
  126: startPNG
  125: drawPlot
  111: <reactive:plotObj>
   95: drawReactive
   82: renderFunc
   81: output$mtcarsplot
    1: runApp

Answer 1

The documentation states

You are bound to see the error, if you set suspendWhenHidden = FALSE, as the output object is not available yet until you click on update button.