Question

我想在Shiny中创建一个用户可以使用指定为用户输入的自定义字体作为pdf下载的情节。

具体来说，我想使用pdf("plot.pdf", width = 5, height = 5, family = font.family)之类的pdf函数，其中font.family的值由用户指定。

下面是一个简单的示例：如果我在我的机器上运行该示例，它可以正常工作。但是，当它托管在RStudio闪亮服务器上时，我收到一条错误消息，指出无法找到指定的字体系列。我认为问题是我想要的字体无法在RStudio闪亮服务器上访问，但有没有办法可以包含它们？

server.R

shinyServer(function(input, output) {

output$distPlot <- renderPlot({

plot(1, xlim = c(0, 1), ylim = c(0, 1))
text(.5, .5, "Custom Font!!"
})

output$downloadPlot <- downloadHandler(

  filename = function() {paste('CustomFont.pdf')}, 
  content = function(file){

font.family <- input$font.family

pdf(file, width = 11, height= 8.5, family = font.family)

plot(1, xlim = c(0, 1), ylim = c(0, 1))
text(.5, .5, fonts(), cex = 10)


dev.off()
}, contentType = "image/pdf"
)
})

ui.R

 shinyUI(fluidPage(

 sidebarLayout(
 sidebarPanel(
  selectInput("font.family", "Choose Font", 
              choices = c("Helvetica Neue", "Times New Roman", "Arial")
  ),
  downloadButton("downloadPlot", "Download Plot as PDF")
),

# Show a plot of the plot
mainPanel(
  plotOutput("distPlot", width = "800px", height = "800px")
  ))))

Answer 1

我有a similar problem。为了解决这个问题，很多renderPlot（）功能都是使用renderImage（）重新创建的，如this Shiny tutorial article中所述。然后字体渲染按照需要工作。

这是解决这个问题的代码;它也可以解决这个问题。

ui.R修改为

mainPanel(
  imageOutput("myImage")
)

server.R

shinyServer(function(input, output, session) {

  # A dynamically-sized plot
  output$myImage <- renderImage({
    # Read myImage's width and height. These are reactive values, so this
    # expression will re-run whenever they change.
    width  <- session$clientData$output_myImage_width
    height <- session$clientData$output_myImage_height

    # For high-res displays, this will be greater than 1
    pixelratio <- session$clientData$pixelratio

    # A temp file to save the output.
    outfile <- tempfile(fileext='.png')

    # Generate the image file
    png(outfile, width=width*pixelratio, height=height*pixelratio,
        res=72*pixelratio)
    plot(rnorm(100), rnorm(100), family="serif")
    dev.off()

    # Return a list containing the filename
    list(src = outfile,
         width = width,
         height = height,
         alt = "This is alternate text")
  }, deleteFile = TRUE) # delete the temp file when finished

})

如何在R Shiny图中使用不同的字体

1 个答案: