Can we bind three plots using rbind_gtable in shiny dashboard to download all the plots together? - ggplot2

Question

Trouble combining multiple shiny plots and downloading through a single click.
Code below is from the answer here: Solution
I tried this solution. It works fine for two plots but as soon as I add another plot it only returns the graph information but not the graph themselves.
Combining two plots works fine.
I also tried other solutions but both of the solutions when implemented returns a text file instead of pdf or pdf file that is corrupted.
Solution1
Solution2
Any suggestion would be really appreciated. Thank you!
Code
library(ggplot2)
ui <- shinyUI(fluidPage(
titlePanel("Test app"),
fluidRow(
column(4,
wellPanel(
downloadButton('download',label="Download plot as png")
)
),
column(8,
plotOutput("plot")
)
)
))
server <- function(input,output) {
plotting<- reactive({
data1=data.frame(x=rnorm(50),y=rnorm(50))
data2=data.frame(x=rexp(50),y=rexp(50))
data3=data.frame(x=rexp(50),y=rexp(50))
plot1=ggplot(data1,aes(x,y))+geom_point()
plot2=ggplot(data2,aes(x,y))+geom_point()
plot3=ggplot(data3,aes(x,y))+geom_point()
gb1=ggplot_build(plot1)
gb2=ggplot_build(plot2)
gb3=ggplot_build(plot3)
gA <- ggplot_gtable(gb1)
gB <- ggplot_gtable(gb2)
gC <- ggplot_gtable(gb3)
both <- gtable:::rbind_gtable(gA, gB, "last")
all <- gtable:::rbind_gtable(both, gC, "last")
return(all)
})
output$plot <- renderPlot({
grid.newpage()
grid.draw(plotting())
})
output$download <- downloadHandler(
filename <- "shinytestplot.png",
# Changes:
content <- function(file){ ## file = NULL --> file
png(file) # filename --> file
grid.newpage()
grid.draw(plotting())
dev.off()
}
)
}
shinyApp(server=server,ui=ui)

Answer 1

Your example works just fine for me. However, I'd recommend against rbinding plots. Use the patchwork package instead.
library(ggplot2)
library(shiny)
library(patchwork)
ui <- shinyUI(fluidPage(
titlePanel("Test app"),
fluidRow(
column(4,
wellPanel(
downloadButton('download',label="Download plot as png")
)
),
column(8,
plotOutput("plot")
)
)
))
server <- function(input,output) {
plotting<- reactive({
data1=data.frame(x=rnorm(50),y=rnorm(50))
data2=data.frame(x=rexp(50),y=rexp(50))
data3=data.frame(x=rexp(50),y=rexp(50))
plot1=ggplot(data1,aes(x,y))+geom_point()
plot2=ggplot(data2,aes(x,y))+geom_point()
plot3=ggplot(data3,aes(x,y))+geom_point()
# stack the plots on top of one another with patchwork
plot1 / plot2 / plot3
})
output$plot <- renderPlot({
print(plotting())
})
output$download <- downloadHandler(
filename <- "shinytestplot.png",
# Changes:
content <- function(file){
ggsave(file, plotting())
}
)
}
shinyApp(server=server,ui=ui)