Download multiple plotly plots to PDF Shiny

Question

My Shiny App displays a plotly plot for whatever input the user selects. I want a download button that saves ALL the plots inside a PDF file on the user\'s system. I\'m using R

Answer 1

I think @Stanislaus Stadlmann is on point. For some reason, plotly::export does not work inside a loop of a rmarkdown file. I suspect it is for the same reason knitr::include_graphic does not work inside a loop. A workaround is to use the markdown syntax to insert your images. Here is the rmarkdown file that works:

---
title: "Report"
output: pdf_document
always_allow_html: yes
params:
  n: NA
---

```{r,echo=FALSE,warning=FALSE, results="asis"}
library(plotly)

for (item in params$n) {
  tmpFile <- tempfile(fileext = ".png")
  export(item, file = tmpFile)
  cat("![](",tmpFile,")\n")
}
```

And this is my downloadplot1 function:

  output$downloadplot1 <-  downloadHandler(
    filename = "plots.pdf",
    content = function(file){

      tempReport <- file.path(tempdir(), "report1.Rmd")
      file.copy("download_content.Rmd", tempReport, overwrite = TRUE)

      list.of.measurands <- c("Measurand1", "Measurand2") #....all my measurands

      plots.gen <- lapply(list.of.measurands, function(msrnd){
        plot_ly(dummy.df, x = c(1:nrow(dummy.df)), y = ~get(msrnd), type = 'scatter', mode = 'markers')
      })

      params <- list(n = plots.gen)

      rmarkdown::render(tempReport, output_file = file,
                        params = params,
                        envir = new.env(parent = globalenv())
      )
    }
  )