Plotly 'Download as png' resizing image when used in RShiny application - r

Question

I'm using plotly package for R to display some large graphs in my shiny application, the graphs display nicely as intended. However, when I click the "Download as png" button, the downloaded .png has been resized. here is a demo of this behavior.
How can I specify the resolution for the exported plot?
Here is a minimal example that demonstates the issue by having a really long title that gets clipped on download
app.R
library(shiny)
library(ggplot2)
library(plotly)
ui <- fluidPage(titlePanel("Plotly Download demo"),
plotlyOutput("demoPlotly"))
server <- function(input, output) {
output$demoPlotly <- renderPlotly({
#make an arbritrary graph with a long title
p <- iris %>%
ggplot(aes(x = Petal.Length, y = Petal.Width, color = Species)) +
geom_point() +
labs(title = "This is a really long title to demo my problem of plotly resizing my downloaded output")
ggplotly(p)
})
}
# Run the application
shinyApp(ui = ui, server = server)
The downloaded graph looks like this:

Answer 1

Michael,
Take a look at plotly_IMAGE(). [Version 4.7.1]. The function does allow you to specify width and height for the saved image. For example 800 by 600.
Regarding your example, I have provided an example of how you might modify the layout to accommodate the title wrapping. Note the changes the margin and padding. I also inserted a call to plotly_IMAGE to provide a simplified example of its usage - it slows things down as it is in line with the plot generation. I'd recommend you add a button and separate out from image display.
Hope this helps
Take care
T.
Pre-requisite - Plotly Credentials:
To use this plotly example you need to register and obtain a plotly api key. Once obtained you need add these entries to your ~/.Renviron file.
Ref: https://plot.ly/r/getting-started/
Example .Renviron file entries
plotly_username="xxxxx"
plotly_api_key="xxxxxx"
Example Code
library(shiny)
library(ggplot2)
library(plotly)
wrapper <- function(x, ...) {
paste(strwrap(x, ...), collapse = "\n")
}
# Example usage wrapper(my_title, width = 20)
my_title <- "This is a really long title to demo my problem of plotly resizing my downloaded output"
ui <- fluidPage(titlePanel("Plotly Download demo"), plotlyOutput("demoPlotly"))
pal <- c("blue", "red", "green")
pal <- setNames(pal, c("virginica", "setosa", "versicolor"))
layout <- list(title = wrapper(my_title, width = 60),
xaxis = list(title = "Petal Length"),
yaxis = list(title = "Petal Width"),
margin = list(l = 50, r = 50, b = 100, t = 100, pad = 4))
server <- function(input, output) {
output$demoPlotly <- renderPlotly({
# make an arbitrary graph with a long title
p <- iris %>%
plot_ly(x = ~Sepal.Length,
y = ~Petal.Width,
color = ~Species,
colors = pal,
mode = "markers",
type = "scatter") %>%
layout(autosize = F,
title = layout$title,
xaxis = layout$xaxis,
yaxis = layout$yaxis,
margin = layout$margin)
p$elementId <- NULL
# Example usage of plotly image
plotly_IMAGE(p,
width = 800,
height = 600,
format = "png",
scale = 1,
out_file = "output.png")
p
})
}
# Run the application
shinyApp(ui = ui, server = server)
Screen Shot Image - screen capture
Plotly save - screen click
plotly_IMAGE() save image output 800 by 600