Question

我正在学习R Shiny并且一直在玩画廊中的各种例子。对于“图像输出”示例：

http://shiny.rstudio.com/gallery/image-output.html

当我选择链环或笑脸单选按钮时，我想知道如何能够包含图像标题。例如，在选择“笑脸”之后，我希望标题“笑脸”显示在图像下方。谢谢您的帮助。以下是上面链接中包含的代码。（为清楚起见，有些是故意删除的）。谢谢

library(png) # For writePNG function

shinyServer(function(input, output, session) {

# A temp file to save the output.
# This file will be automatically removed later by
# renderImage, because of the deleteFile=TRUE argument.
outfile <- tempfile(fileext = ".png")

# Generate the image and write it to file
x <- matrix(rep((0:(width-1))/(width-1), height), height,
            byrow = TRUE)
y <- matrix(rep((0:(height-1))/(height-1), width), height)
pic <- gauss2d(x, y, input$r)
writePNG(pic, target = outfile)

# Return a list containing information about the image
list(src = outfile,
     contentType = "image/png",
     width = width,
     height = height,
     alt = "This is alternate text")

}, deleteFile = TRUE)


# image2 sends pre-rendered images
output$image2 <- renderImage({
if (is.null(input$picture))
  return(NULL)

if (input$picture == "face") {
  return(list(
    src = "images/face.png",
    contentType = "image/png",
    alt = "Face"
  ))
} else if (input$picture == "chainring") {
  return(list(
    src = "images/chainring.jpg",
    filetype = "image/jpeg",
    alt = "This is a chainring"
  ))
}

}, deleteFile = FALSE)
 })







shinyUI(fluidPage(
titlePanel("Client data and query string example"),

fluidRow(
column(4, wellPanel(
  sliderInput("r", "Radius :", min = 0.05, max = 1,
              value = 0.2, step = 0.05),
  radioButtons("picture", "Picture:",
              c("chainring", "face"))
)),
column(4,
  imageOutput("image1", height = 300),
  imageOutput("image2")
)
)

Answer 1

这有帮助吗？

ui.R

    library(shiny)
    shinyUI(fluidPage(
      titlePanel("Image title"),
      sidebarLayout(
        sidebarPanel(
                sliderInput("obs", "Number of observations:",
                            min = 0, max = 1000,  value = 500)
        ),
        mainPanel(
                imageOutput("myImage"),
                uiOutput("text")

        )
      )
    ))

server.R

    library(shiny)

    shinyServer(function(input, output) {

            output$myImage <- renderImage({
                    outfile <- tempfile(fileext='.png')

                    png(outfile, width=400, height=300)
                    hist(rnorm(input$obs), main = "")
                    dev.off()

                    list(src = outfile,
                         contentType = 'image/png',
                         width = 400,
                         height = 300,
                         alt = "This is alternate text")
            }, deleteFile = TRUE)
            histogramTitle <- reactive({
                    paste("<h5>", input$obs, " observation used to create the histogram</h5>", sep = "")
            })
            output$text <- renderUI({   
                    HTML(as.character(histogramTitle()))
            })
    })

带图像的输出标题

1 个答案: