mirror of
https://github.com/rstudio/shiny.git
synced 2026-02-02 10:45:06 -05:00
101 lines
3.2 KiB
R
101 lines
3.2 KiB
R
% Generated by roxygen2 (4.0.0): do not edit by hand
|
|
\name{renderImage}
|
|
\alias{renderImage}
|
|
\title{Image file output}
|
|
\usage{
|
|
renderImage(expr, env = parent.frame(), quoted = FALSE, deleteFile = TRUE)
|
|
}
|
|
\arguments{
|
|
\item{expr}{An expression that returns a list.}
|
|
|
|
\item{env}{The environment in which to evaluate \code{expr}.}
|
|
|
|
\item{quoted}{Is \code{expr} a quoted expression (with \code{quote()})? This
|
|
is useful if you want to save an expression in a variable.}
|
|
|
|
\item{deleteFile}{Should the file in \code{func()$src} be deleted after
|
|
it is sent to the client browser? Generally speaking, if the image is a
|
|
temp file generated within \code{func}, then this should be \code{TRUE};
|
|
if the image is not a temp file, this should be \code{FALSE}.}
|
|
}
|
|
\description{
|
|
Renders a reactive image that is suitable for assigning to an \code{output}
|
|
slot.
|
|
}
|
|
\details{
|
|
The expression \code{expr} must return a list containing the attributes for
|
|
the \code{img} object on the client web page. For the image to display,
|
|
properly, the list must have at least one entry, \code{src}, which is the
|
|
path to the image file. It may also useful to have a \code{contentType}
|
|
entry specifying the MIME type of the image. If one is not provided,
|
|
\code{renderImage} will try to autodetect the type, based on the file
|
|
extension.
|
|
|
|
Other elements such as \code{width}, \code{height}, \code{class}, and
|
|
\code{alt}, can also be added to the list, and they will be used as
|
|
attributes in the \code{img} object.
|
|
|
|
The corresponding HTML output tag should be \code{div} or \code{img} and have
|
|
the CSS class name \code{shiny-image-output}.
|
|
}
|
|
\examples{
|
|
\dontrun{
|
|
|
|
shinyServer(function(input, output, clientData) {
|
|
|
|
# A plot of fixed size
|
|
output$plot1 <- renderImage({
|
|
# A temp file to save the output. It will be deleted after renderImage
|
|
# sends it, because deleteFile=TRUE.
|
|
outfile <- tempfile(fileext='.png')
|
|
|
|
# Generate a png
|
|
png(outfile, width=400, height=400)
|
|
hist(rnorm(input$n))
|
|
dev.off()
|
|
|
|
# Return a list
|
|
list(src = outfile,
|
|
alt = "This is alternate text")
|
|
}, deleteFile = TRUE)
|
|
|
|
# A dynamically-sized plot
|
|
output$plot2 <- renderImage({
|
|
# Read plot2's width and height. These are reactive values, so this
|
|
# expression will re-run whenever these values change.
|
|
width <- clientData$output_plot2_width
|
|
height <- clientData$output_plot2_height
|
|
|
|
# A temp file to save the output.
|
|
outfile <- tempfile(fileext='.png')
|
|
|
|
png(outfile, width=width, height=height)
|
|
hist(rnorm(input$obs))
|
|
dev.off()
|
|
|
|
# Return a list containing the filename
|
|
list(src = outfile,
|
|
width = width,
|
|
height = height,
|
|
alt = "This is alternate text")
|
|
}, deleteFile = TRUE)
|
|
|
|
# Send a pre-rendered image, and don't delete the image after sending it
|
|
output$plot3 <- renderImage({
|
|
# When input$n is 1, filename is ./images/image1.jpeg
|
|
filename <- normalizePath(file.path('./images',
|
|
paste('image', input$n, '.jpeg', sep='')))
|
|
|
|
# Return a list containing the filename
|
|
list(src = filename)
|
|
}, deleteFile = FALSE)
|
|
})
|
|
|
|
}
|
|
}
|
|
\seealso{
|
|
For more details on how the images are generated, and how to control
|
|
the output, see \code{\link{plotPNG}}.
|
|
}
|
|
|