R Shiny节省反应性ggplots

Question

我正试图弄清楚如何在我的R Shiny项目中保存反应性ggplots.我已经按照本指南以及R Shiny网站上的指南进行了操作.但是,我想我可能会遇到一个问题,因为我正在使用反应情节.

这是我到目前为止的代码.

ui <- fluidPage(

    dashboardBody(
      fluidRow(uiOutput('topbox')),
      fluidRow(
        tabBox(
          id = 'tabset1',
          width = '100%',
          tabPanel('Grades Graph', downloadButton('Download'), plotOutput('individualGraph')),
        )
      )
    )
  )

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

  grades <- reactive({
    req(input$file)
    inFile <- input$file
    if (endsWith(inFile$name, '.xlsx')){
      gradesTbl <- read_excel(inFile$datapath)
      gradesTbl <- gradesTbl %>% 
        arrange(Period, Student, Date, Type) %>% 
        mutate(Date = as.Date(Date))
      return(gradesTbl)
    } else if (endsWith(inFile$name, 'csv')){
      gradesTbl <- read_csv(inFile$datapath)
      gradesTbl <- gradesTbl %>% 
        arrange(Period, Student, Date, Type) %>% 
        mutate(Date = mdy(Date))
      return(gradesTbl)
    }
  })

  output$Download <- downloadHandler(
   filename = function(){
     paste('test', '.png', sep = '')
   },
   content = function(file){
     ggsave(file, plot = output$individualGraph, device = 'png')
   }
  )

  indivdf <- function(){
    data.frame(grades()) %>%
      filter((Student == input$studentVar) & (Period == input$periodVar) & (Type %in% input$typeVar) & (Unit %in% input$unitVar))
  }

  output$individualGraph <- renderPlot({
    req(input$periodVar)
    indivdf() %>%
      ggplot(aes(x = Date, y = Grade,
                 color = Type, shape = Unit)) +
      geom_point(size = 4) +
      ggtitle(paste(input$studentVar, "'s Individual Grades", sep = '')) +
      plotTheme() +
      scale_shape_manual(values = 1:10) +
      facet_wrap(Unit~.) +
      scale_color_manual(values = c('#E51A1D', '#377DB9', '#4EAE4A'))
  })

shinyApp(ui = ui, server = server)

完整的代码在这里,但我认为这是显示我正在尝试做的一切.我只是无法弄清楚如何保存这些表和反应图.我觉得这与使用'plot = output $ indididualGraph'有关,但我真的不知道.

Answer 1

您需要使用代码生成绘图并将其从renderPlota 移动到reactive.然后你可以reactive从内部调用相同的内容renderPlot来在UI中显示图形,并从中downloadHandler下载图表.

请参阅下面的示例.对reactive(individualGraph())和输出return(output$individualGraph)使用相同的变量名称可能不是最好的编码实践,但我发现它更方便.

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

    individualGraph <- reactive({
        req(input$periodVar)
        indivdf() %>%
            ggplot(aes(x = Date, y = Grade,
                       color = Type, shape = Unit)) +
            geom_point(size = 4) +
            ggtitle(paste(input$studentVar, "'s Individual Grades", sep = '')) +
            plotTheme() +
            scale_shape_manual(values = 1:10) +
            facet_wrap(Unit~.) +
            scale_color_manual(values = c('#E51A1D', '#377DB9', '#4EAE4A'))
    })

    output$individualGraph <- renderPlot({
        req(individualGraph())
        individualGraph()
    })

    output$Download <- downloadHandler(
        filename = function(){
            paste('test', '.png', sep = '')
        },
        content = function(file){
            req(individualGraph())
            ggsave(file, plot = individualGraph(), device = 'png')
        }
    )

    grades <- reactive({
        req(input$file)
        inFile <- input$file
        if (endsWith(inFile$name, '.xlsx')){
            gradesTbl <- read_excel(inFile$datapath)
            gradesTbl <- gradesTbl %>% 
                arrange(Period, Student, Date, Type) %>% 
                mutate(Date = as.Date(Date))
            return(gradesTbl)
        } else if (endsWith(inFile$name, 'csv')){
            gradesTbl <- read_csv(inFile$datapath)
            gradesTbl <- gradesTbl %>% 
                arrange(Period, Student, Date, Type) %>% 
                mutate(Date = mdy(Date))
            return(gradesTbl)
        }
    })

    indivdf <- function(){
        data.frame(grades()) %>%
            filter((Student == input$studentVar) & (Period == input$periodVar) & (Type %in% input$typeVar) & (Unit %in% input$unitVar))
    }
}