从Shiny(R)下载png [英] Downloading png from Shiny (R)
问题描述
我对Shiny(和R)来说很新,并且将Shiny中的情节导出到png文件中。
我看了这两个线程,但无法弄清楚:
在闪亮的应用程序中保存的地图
闪亮的downloadHandler不保存PNG文件
我设法在ui中创建下载按钮,服务器似乎也在做我想做的一切。当我在预览窗口中点击下载按钮时,弹出窗口要求我指定文件的位置和名称,但不保存任何文件。当我在浏览器窗口中执行相同操作时,会创建一个png文件,但它是空的。
任何见解非常感谢!
ui.R
$ b $
$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ b sidebarLayout(
sidebarPanel(
fileInput('datafile','Choose CSV file',
accept = c('text / csv','text / value,text / plain'))
uiOutput(varselect1),
uiOutput(varselect2),
downloadButton('
mainPanel(
h4(这是你的散点图),
plotOutput(plot1 )
)
))
)
server.R
library(foreign)
ShinyServer(function(session,input,output)){
DataInput< --active({
infile< - input $ datafile
if(is.null(infile)){
return(NULL)
}
read.csv(infile $ datapath)
})
输出$ varselect1 < - renderUI({
if(identical(DataInput(),'')||相同(DataInput(),data.frame()))return(NULL)
cols< - 名称(DataInput())
selectInput(var1,选择一个变量: ,choices = c(---,cols [3:length(cols)]),selected =(---))
})
输出$ varselect2< - renderUI({
if(identical(DataInput(),'')|| same(DataInput(),data.frame()))return(NULL)
cols< - names(DataInput())
selectInput(var2,选择一个变量:,choices = c(---,cols [3:length )]),selected =(---))
})
plotInput< - reactive({
a < - which(names(DataInput())== input $ var1)
x_lab< - as.numeric(DataInput()[,a])
b< - 其中(name(DataInput())==输入$ var2)
y_lab< - as.numeric(DataInput()[,b])
main .text< - paste(Scatterplot of the variables,colnames(DataInput())[a],and,colnames(DataInput())[b],sep =,collapse = NULL )
plot(x_lab,y_lab,main = main.text,xlab = colnames(DataInput())[a],ylab = colnames(DataInput())[b],xlim = c (x_lab),max(x_lab)* 1.05),ylim = c(min(y_lab),max(y_lab)* 1.05))
观察< - DataInput()[,1]
文本(x_lab,y_lab,labels = observations,pos = 3)
})
输出$ plot1< - renderPlot {
print(plotInput())
})
输出$ downloadPlot< - downloadHandler(
filename =Shinyplot.png,
content = function(file){
png(file)
print(plotInput())
dev.off()
})
})
已经讨论了这个奇怪场景的解决方法在闪亮讨论的Google群组。您可以做的只是将您的反应性 plotInput
语句更改为正常的功能。不确定为什么 downloadHandler
对于反应对象不会很好。
#change
plotInput< - reactive({...})
#into this
plotInput< - function(){...}
您还可以删除 downloadHandler
调用中的print语句:
输出$ downloadPlot< - downloadHandler(
filename =Shinyplot.png,
content = function (文件){
png(file)
plotInput()
dev.off()
})
I am pretty new to Shiny (and R) and struggling with exporting the plot I make in Shiny to a png-file.
I looked at these two threads but could not figure it out:
Save plots made in a shiny app Shiny downloadHandler doesn't save PNG files
I manage to create the download button in the ui and the server seems to be doing everything I want it to do, too. When I hit the download button in the preview window, a pop up window asks me to specify the file location and name but no file is saved. When I do the same in a browser window, a png file is created but it is empty.
Any insight is much appreciated!
ui.R
library(shiny)
shinyUI(fluidPage(
titlePanel("This is a scatterplot"),
sidebarLayout(
sidebarPanel(
fileInput('datafile', 'Choose CSV file',
accept=c('text/csv', 'text/comma-separated-values,text/plain')),
uiOutput("varselect1"),
uiOutput("varselect2"),
downloadButton('downloadPlot', 'Download Plot')
),
mainPanel(
h4("Here is your scatterplot"),
plotOutput("plot1")
)
))
)
server.R
library(foreign)
shinyServer(function(session,input, output) {
DataInput <- reactive({
infile <- input$datafile
if (is.null(infile)) {
return(NULL)
}
read.csv(infile$datapath)
})
output$varselect1 <- renderUI({
if (identical(DataInput(), '') || identical(DataInput(),data.frame())) return(NULL)
cols <- names(DataInput())
selectInput("var1", "Select a variable:",choices=c("---",cols[3:length(cols)]), selected=("---"))
})
output$varselect2 <- renderUI({
if (identical(DataInput(), '') || identical(DataInput(),data.frame())) return(NULL)
cols <- names(DataInput())
selectInput("var2", "Select a variable:",choices=c("---",cols[3:length(cols)]), selected=("---"))
})
plotInput <- reactive({
a <- which(names(DataInput())==input$var1)
x_lab <- as.numeric(DataInput()[,a])
b <- which(names(DataInput())==input$var2)
y_lab <- as.numeric(DataInput()[,b])
main.text <- paste("Scatterplot of the variables",colnames(DataInput())[a],"and", colnames(DataInput())[b],sep = " ", collapse = NULL)
plot(x_lab, y_lab, main=main.text, xlab=colnames(DataInput())[a], ylab=colnames(DataInput())[b], xlim=c(min(x_lab),max(x_lab)*1.05), ylim=c(min(y_lab), max(y_lab)*1.05))
observations <- DataInput()[,1]
text(x_lab, y_lab, labels=observations, pos=3)
})
output$plot1 <- renderPlot({
print(plotInput())
})
output$downloadPlot <- downloadHandler(
filename = "Shinyplot.png",
content = function(file) {
png(file)
print(plotInput())
dev.off()
})
})
A workaround for this strange scenario was discussed on the shiny-discuss google group. What you can do is simply change your reactive plotInput
statement into a normal function. Not sure why downloadHandler
doesn't play nice with reactive objects.
# change
plotInput <- reactive({...})
# into this
plotInput <- function(){...}
You can also remove the print statement in the downloadHandler
call:
output$downloadPlot <- downloadHandler(
filename = "Shinyplot.png",
content = function(file) {
png(file)
plotInput()
dev.off()
})
这篇关于从Shiny(R)下载png的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!