上传一张图片到R shiny，下载到pdf

fileInput("fileUpload", "上传图片", accept = c('.jpg', '.png', '.jpeg'))

observeEvent(input$fileUpload, {
  inFile <- input$fileUpload
  if (!is.null(inFile)) {
    filepath <- inFile$datapath
    # 进行后续操作，如将文件保存到指定目录中或进行其他处理
  }
})

output$downloadPDF <- downloadHandler(
  filename = function() {
    paste("downloaded_image.pdf", sep = "")
  },
  content = function(file) {
    img <- image_read(filepath)  # 使用magick包读取上传的图片
    img_pdf <- image_convert(img, "pdf")  # 将图片转换为PDF格式
    image_write(img_pdf, path = file)  # 将PDF文件写入临时目录
  }
)

downloadButton("downloadButton", "下载PDF")

library(shiny)
library(shinyFiles)
library(magick)

ui <- fluidPage(
  titlePanel("上传图片并下载为PDF"),
  sidebarLayout(
    sidebarPanel(
      fileInput("fileUpload", "上传图片", accept = c('.jpg', '.png', '.jpeg')),
      downloadButton("downloadButton", "下载PDF")
    ),
    mainPanel(
      textOutput("message")
    )
  )
)

server <- function(input, output) {
  observeEvent(input$fileUpload, {
    inFile <- input$fileUpload
    if (!is.null(inFile)) {
      filepath <- inFile$datapath
      output$message <- renderText({
        paste("已上传的文件路径：", filepath)
      })
    }
  })
  
  output$downloadPDF <- downloadHandler(
    filename = function() {
      paste("downloaded_image.pdf", sep = "")
    },
    content = function(file) {
      img <- image_read(filepath)
      img_pdf <- image_convert(img, "pdf")
      image_write(img_pdf, path = file)
    }
  )
}

shinyApp(ui = ui, server = server)