闪亮应用程序中的 renderImage() 和 .svg

Question

我无法renderImage()使用 .svg 文件。我的最小示例（改编自相应的 RStudio-tutorial）：

用户界面

shinyUI(pageWithSidebar(
  headerPanel("renderSVG example"),
  sidebarPanel(
    sliderInput("obs", "Number of observations:",
                min = 0, max = 1000,  value = 500),
    actionButton("savePlot", "savePlot")
  ),
  mainPanel(
    # Use imageOutput to place the image on the page
    imageOutput("plot"),
    imageOutput("plot_as_svg")
  )
))

服务器

require("ggplot2")
library(svglite)

shinyServer(function(input, output, session) {
  
  ## create plot with renderPlot() 
  

      output$plot<- renderPlot({
        hist(rnorm(input$obs), main="Generated in renderPlot()")
        })

  
  ## create .svg file of the plot and render it with renderImage() 
  
  output$plot_as_svg <- renderImage({
    # A temp file to save the output.
    # This file will be removed later by renderImage
    outfile <- tempfile(fileext='.svg')
    
    # Generate the svg
    svglite(outfile, width=400, height=300)
    hist(rnorm(input$obs), main="Generated in renderImage()")
    dev.off()
    
    # Return a list containing the filename
    list(src = outfile,
         contentType = 'text/svg+xml',
         width = 400,
         height = 300,
         alt = "This is alternate text")
  }, deleteFile = TRUE)
  
})

任何想法问题出在哪里？

Answer 1

受到上面基本图形的 R_User123456789s 解决方案（此处）的启发，我使用 ggplot2 通过以下方式得到了它

用户界面

shinyUI(pageWithSidebar(
  headerPanel("renderSVG example"),
  sidebarPanel(
    sliderInput("obs", "Number of observations:",
                min = 0, max = 1000,  value = 500)
  ),
  mainPanel(
    # Use imageOutput to place the image on the page
    imageOutput("plot"),
    imageOutput("plot_as_svg")
  )
))

服务器.r

require("ggplot2")

shinyServer(function(input, output, session) {

  ## create plot with renderPlot()


  output$plot<- renderPlot({
    hist(rnorm(input$obs), main="Generated in renderPlot() as png")
  })


  ## create .svg file of the plot and render it with renderImage()

  output$plot_as_svg <- renderImage({

    width  <- session$clientData$output_plot_width
    height <- session$clientData$output_plot_height
    mysvgwidth <- width/96
    mysvgheight <- height/96

    # A temp file to save the output.
    # This file will be removed later by renderImage

    outfile <- tempfile(fileext='.svg')

    # Generate the svg
    #to see actually what will be plotted and compare 
    qplot(clarity, data=diamonds, fill=cut, geom="bar")
    #save the plot in a variable image to be able to export to svg
    image=qplot(clarity, data=diamonds[1:input$obs,], fill=cut, geom="bar", main = "ggplot as svg")
    #This actually save the plot in a image
    ggsave(file=outfile, plot=image, width=mysvgwidth, height=mysvgheight)

    # Return a list containing the filename
    list(src = normalizePath(outfile),
         contentType = 'image/svg+xml',
         width = width,
         height = height,
         alt = "My svg Histogram")
  })

})