在 pdf 输出shiny 的标题中渲染 logo.png Rmarkdown

这是一个后续问题，或者是对这个问题的简化

通过这个Rmarkdown代码，我可以实现我想要的:

logo.png

report.Rmd

---
geometry: margin=20truemm
fontfamily: mathpazo
fontsize: 11pt
documentclass: article
classoption: a4paper
urlcolor: blue
output: 
    pdf_document:
header-includes:
   - \usepackage{fancyhdr}
   - \pagestyle{fancy}
   - \rhead{\includegraphics[width = .05\textwidth]{logo.png}}
params: 
    scores: NA
---
<!-- ```{r, echo=FALSE} -->
<!-- hist(params$scores) -->
<!-- ``` -->

```{r}
hist(runif(100))
```

Getting desired output: The R logo is in the header:

现在我想在一个shiny 的应用程序上做同样的事情

For this I pass the plot as a parameter and uncomment the relevant part in the report.Rmd file

report.Rmd文件中的相关部分:

```{r, echo=FALSE}
hist(params$scores)
```

app.R

# Global variables can go here
n <- 200


# Define the UI
ui <- bootstrapPage(
  numericInput('n', 'Number of obs', n),
  plotOutput('plot'),
  downloadButton('report', 'Generate Report')
)


# Define the server code
server <- function(input, output) {
  output$plot <- renderPlot({
    hist(runif(input$n))
  })
  
  # create markdown report  ----------------------------------
  
  output$report <- downloadHandler(
    filename = "report.pdf",
    content = function(file) {
      tempReport <- file.path(tempdir(), "report.Rmd")
      file.copy("report.Rmd", tempReport, overwrite = TRUE)
      
      params <- list(scores = input$n)
      
      rmarkdown::render(tempReport, output_file = file,
                        params = params,
                        envir = new.env(parent = globalenv())
      )
    }
  )
  
}

# Return a Shiny app object
shinyApp(ui = ui, server = server)

Error:

! Package pdftex.def Error: File `logo.png' not found: using draft setting.

我怀疑是因为它在本地起作用.在保存临时报告的临时文件中找不到png

但我不知道为什么这在markdown上编织时有效，而在shiny应用程序上调用时无效.