R:快速反应图像显示
我正在尝试在我的闪亮应用程序中显示图像。我已在服务器.R的脚本中成功地完成了这项工作:R:快速反应图像显示,r,image,shiny,reactive-programming,R,Image,Shiny,Reactive Programming,我正在尝试在我的闪亮应用程序中显示图像。我已在服务器.R的脚本中成功地完成了这项工作: output$display.image <- renderImage({ image_file <- paste("www/",input$image.type,".jpeg",sep="") return(list( src = image_file, filetype = "image/jpeg", height = 520,
output$display.image <- renderImage({
image_file <- paste("www/",input$image.type,".jpeg",sep="")
return(list(
src = image_file,
filetype = "image/jpeg",
height = 520,
width = 696
))
}, deleteFile = FALSE)
为什么会有这样的差异?有没有办法使反应图像显示得更快?您好,您可以使用
conditionalPanel
来执行此操作,它会嵌入您的所有图像,但只有符合TRUE
条件的图像才会显示:
tabPanel("Live Images",
conditionalPanel(condition = "input.image_type == 'img_type1'",
img(src = "img_type1.jpeg")
),
conditionalPanel(condition = "input.image_type == 'img_type2'",
img(src = "img_type2.jpeg")
)
)
并将输入的名称从image.type
更改为image\u type
,因为
在Javascript中有特殊含义(介于input
和image\u type
之间)
如果你有很多图像,你总是可以这样做:
tabPanel("Live Images",
lapply(X = seq_len(10), FUN = function(i) {
conditionalPanel(condition = paste0("input.image_type == 'img_type", i, "'"),
img(src = paste0("img_type", i, ".jpeg"))
)
})
)
例如,对于来自此by的图像(您也可以在rbloggers上找到),您可以执行以下操作:
library("shiny")
ui <- fluidPage(
tabsetPanel(
tabPanel("Live Images",
# 50 images to display
lapply(X = seq_len(50), FUN = function(i) {
# condition on the slider value
conditionalPanel(condition = paste0("input.slider == ", i),
# images are on github
img(src = paste0("https://raw.githubusercontent.com/pvictor/images/master/",
sprintf("%04d", i), "plot.png"))
)
}),
sliderInput(inputId = "slider", label = "Value", min = 1, max = 50, value = 1,
animate = animationOptions(interval = 100, loop = TRUE))
)
)
)
server <- function(input, output) {
}
shinyApp(ui = ui, server = server)
库(“闪亮”)
ui当您从反应式服务器发送图像URL时,您正在通过JavaScript从服务器传输到客户端。这些数据需要由客户端解包并用于转换文档,这一切都需要时间。你的要求是什么?图像是否需要动态加载?是否有一组有限的图像可以加载?@sdgfsdh需要根据用户输入(input$image.type)动态加载图像,是的,有一组有限的图像可以加载。
library("shiny")
ui <- fluidPage(
tabsetPanel(
tabPanel("Live Images",
# 50 images to display
lapply(X = seq_len(50), FUN = function(i) {
# condition on the slider value
conditionalPanel(condition = paste0("input.slider == ", i),
# images are on github
img(src = paste0("https://raw.githubusercontent.com/pvictor/images/master/",
sprintf("%04d", i), "plot.png"))
)
}),
sliderInput(inputId = "slider", label = "Value", min = 1, max = 50, value = 1,
animate = animationOptions(interval = 100, loop = TRUE))
)
)
)
server <- function(input, output) {
}
shinyApp(ui = ui, server = server)