R 可下载的Plot Shining模块不显示在Shining应用程序中

我有下面的

shinny

应用程序，我想知道如何使用

downloadablePlot

shinny模块下载绘图。启动应用程序时，visibleplot中出现

错误：找不到函数“visibleplot”

。它应该通过

shinny

包加载，按钮不显示

library(shiny)
library(periscope)
ui <- fluidPage(
  plotOutput("plot"),
  downloadablePlotUI("object_id1", 
                     downloadtypes = c("png", "csv"), 
                     download_hovertext = "Download the plot and data here!",
                     height = "500px", 
                     btn_halign = "left")
)

server <- function(input, output) {
  output$plot<-renderPlot(plot(iris))
  plotInput = function() {
    plot(iris)
  }
  callModule(downloadablePlot,
             "object_id1", 
             logger = ss_userAction.Log,
             filenameroot = "mydownload1",
             aspectratio = 1.33,
             downloadfxns = list(png = plotInput),
             visibleplot = plotInput)
  
}

shinyApp(ui = ui, server = server)

库（闪亮）
图书馆（潜望镜）
ui关于
可下载绘图ui
的文档说明如下：

此模块与内置（基本）图形（图形包提供的任何功能，如plot）不兼容，因为它们无法保存到对象中，并且在创建时由系统直接输出

您正在使用无法显示的绘图（iris）

library(shiny)
library(periscope)
ui <- fluidPage(
  plotOutput("plot"),
  downloadablePlotUI("object_id1", 
                     downloadtypes = c("png", "csv"), 
                     download_hovertext = "Download the plot and data here!",
                     height = "500px", 
                     btn_halign = "left")
)

server <- function(input, output) {
  output$plot<-renderPlot(plot(iris))
  plotInput = function() {
    plot(iris)
  }
  callModule(downloadablePlot,
             "object_id1", 
             logger = ss_userAction.Log,
             filenameroot = "mydownload1",
             aspectratio = 1.33,
             downloadfxns = list(png = plotInput),
             visibleplot = plotInput)
  
}

shinyApp(ui = ui, server = server)

使用
ggplot
将显示绘图。我仍然没有得到下载按钮

server <- function(input, output, session) {
  output$plot<-renderPlot(plotInput())
  plotInput <- function() {
    ggplot(cars, aes(x=speed, y=dist))+geom_point()
  }
  plot <- ggplot(cars, aes(x=speed, y=dist))+geom_point()
  callModule(downloadablePlot,
             "object_id1", 
             logger = ss_userAction.Log,
             filenameroot = "mydownload1",
             aspectratio = 1.33,
             downloadfxns = list(png = plotInput),
             visibleplot = plotInput )
  
}

服务器谢谢，那我怎么用呢？