Customizing the Appearance of R Markdown Documents with Shiny and HTML Document Outputs

In this article, we will explore how to customize the appearance of R Markdown documents when using the shiny package for runtime rendering. Specifically, we will focus on removing Bootstrap CSS from the rendered HTML document.

Introduction

R Markdown is a powerful tool for creating documents that combine text, images, and code. The rmarkdown::run() function allows us to render these documents with various output formats, including HTML. When using the shiny package for runtime rendering, we can further customize the appearance of our documents by setting the theme parameter in the YAML header.

Background

The Bootstrap CSS library is a popular front-end framework used for building responsive and mobile-first web applications. However, when working with R Markdown documents, it’s often necessary to remove or customize this CSS library to ensure that your document looks exactly as you want it to.

In this article, we’ll delve into the world of HTML documents, explore how to remove Bootstrap CSS from R Markdown documents rendered with shiny, and discuss some best practices for customizing the appearance of your documents.

Understanding the `render_args` Parameter

When using rmarkdown::run() with the shiny package, we can customize the output format by setting the render_args parameter. This parameter allows us to specify additional options that control how the document is rendered.

In this article, we’ll focus on using the output_format option within the render_args parameter to remove Bootstrap CSS from our HTML document outputs.

Setting the `theme` Parameter

Before we dive into removing Bootstrap CSS, let’s take a look at the theme parameter. This parameter allows us to set a custom theme for our document output.

When using the html_document format, you can set a custom theme by specifying it in the YAML header:

output:
  html_document:
    theme: null

By setting theme: null, we’re effectively disabling any default Bootstrap CSS that might be included with this output format.

Removing Bootstrap CSS with `render_args`

Now, let’s take a closer look at how to remove Bootstrap CSS from our HTML document outputs using the render_args parameter.

When running an R Markdown document with rmarkdown::run(), we can specify additional arguments in the shiny_args list. One of these arguments is render_args, which allows us to customize the output format.

To remove Bootstrap CSS, we need to set the output_format option within the render_args parameter:

rmarkdown::run(
  "test.Rmd", 
  shiny_args = list(
    port = 5050, host = "0.0.0.0", launch.browser = TRUE
  ), 
  render_args = list(
    output_format = rmarkdown::html_document(theme = NULL)
  )
)

By setting output_format = html_document(theme = NULL), we’re telling R Markdown to generate an HTML document without any default Bootstrap CSS.

Additional Options and Best Practices

There are several additional options you can use within the render_args parameter to customize your output format.

For example, you can set base_url to specify a custom base URL for your document:

rmarkdown::run(
  "test.Rmd", 
  shiny_args = list(
    port = 5050, host = "0.0.0.0", launch.browser = TRUE
  ), 
  render_args = list(
    output_format = rmarkdown::html_document(base_url = "https://example.com")
  )
)

You can also set index to specify an alternative index page for your document:

rmarkdown::run(
  "test.Rmd", 
  shiny_args = list(
    port = 5050, host = "0.0.0.0", launch.browser = TRUE
  ), 
  render_args = list(
    output_format = rmarkdown::html_document(index = "index.html")
  )
)

In addition to these options, it’s generally a good idea to use the default_file parameter to specify the main file that R Markdown should use for rendering:

rmarkdown::run(
  "test.Rmd", 
  default_file = "test.Rmd", 
  shiny_args = list(
    port = 5050, host = "0.0.0.0", launch.browser = TRUE
  ), 
  render_args = list(
    output_format = rmarkdown::html_document(theme = NULL)
  )
)

Conclusion

In this article, we explored how to customize the appearance of R Markdown documents when using the shiny package for runtime rendering. Specifically, we discussed how to remove Bootstrap CSS from our HTML document outputs by setting the theme parameter in the YAML header and using the render_args parameter to customize the output format.

By following these best practices and customizing your R Markdown documents accordingly, you can create high-quality, visually appealing documents that meet your specific needs.

Last modified on 2023-12-27