How to create and display an animated GIF in Shiny? - shiny

Question

I'm able to load a saved file as an image but unable to use gganimate to do it directly. Alternate ways of rendering GIFs would be nice to know but knowing how to render gganimate specifically would really solve my problem.
library(gapminder)
library(ggplot2)
library(shiny)
library(gganimate)
theme_set(theme_bw())
ui <- basicPage(
plotOutput("plot1")
)
server <- function(input, output) {
output$plot1 <- renderPlot({
p = ggplot(gapminder, aes(gdpPercap, lifeExp, size = pop, color = continent, frame = year)) +
geom_point() +
scale_x_log10()
gg_animate(p)
})
}
shinyApp(ui, server)

Answer 1

Now that there's a newer breaking version of gganimate, #kt.leap's answer is deprecated. Here's what worked for me with the new gganimate:
library(gapminder)
library(ggplot2)
library(shiny)
library(gganimate)
theme_set(theme_bw())
ui <- basicPage(
imageOutput("plot1"))
server <- function(input, output) {
output$plot1 <- renderImage({
# A temp file to save the output.
# This file will be removed later by renderImage
outfile <- tempfile(fileext='.gif')
# now make the animation
p = ggplot(gapminder, aes(gdpPercap, lifeExp, size = pop,
color = continent)) + geom_point() + scale_x_log10() +
transition_time(year) # New
anim_save("outfile.gif", animate(p)) # New
# Return a list containing the filename
list(src = "outfile.gif",
contentType = 'image/gif'
# width = 400,
# height = 300,
# alt = "This is alternate text"
)}, deleteFile = TRUE)}
shinyApp(ui, server)

Answer 2

I was dealing with the same issue and found only your question and no answers... But the way you phrased it reminded me that renderPlot is finicky:
it won’t send just any image file to the browser – the image must be generated by code that uses R’s graphical output device system. Other methods of creating images can’t be sent by renderPlot()... The solution in these cases is the renderImage() function. source
Modifying the code from that article gives you the following:
library(gapminder)
library(ggplot2)
library(shiny)
library(gganimate)
theme_set(theme_bw())
ui <- basicPage(
imageOutput("plot1"))
server <- function(input, output) {
output$plot1 <- renderImage({
# A temp file to save the output.
# This file will be removed later by renderImage
outfile <- tempfile(fileext='.gif')
# now make the animation
p = ggplot(gapminder, aes(gdpPercap, lifeExp, size = pop,
color = continent, frame = year)) + geom_point() + scale_x_log10()
gg_animate(p,"outfile.gif")
# Return a list containing the filename
list(src = "outfile.gif",
contentType = 'image/gif'
# width = 400,
# height = 300,
# alt = "This is alternate text"
)}, deleteFile = TRUE)}
shinyApp(ui, server)