Wrapper of knitr::include_graphics to Deal with URLs and Invalid File Types

Deals with URL paths and invalid file types passed to path of include_graphics. When the output format of the R Markdown is PDF, and an URL is passed to path, the figure is automatically downloaded from the URL and included using the local relative path. If a figure has an invalid file extension for PDF output (e.g. .gif, .svg), the function passed to handler is used to override the default behavior: inserting figures with knitr::include_graphics.

include_graphics2(path, alt_path = NULL, handler = function(path)
  knitr::asis_output(paste("View", tools::file_ext(path), "at", path)),
  ...)

Arguments

path	String. Path to a figure to be included. Can be either an URL or a local path.
alt_path	String. An alternative figure path for path with invalid extensions. In the case of PDF ('LaTeX') output, invalid extensions are .gif, .svg.
handler	Function. A function with a single argument path. Used to insert alternative contents, such as a piece of text, when the figure cannot be inserted.
...	Other arguments to pass to include_graphics.

Details

Read more about using the function at http://bit.ly/include_graphics2.

Examples

# NOT RUN {
png_url <- 'https://commonmark.org/images/markdown-mark.png'
gif_url <- 'https://media.giphy.com/media/k3dcUPvxuNpK/giphy.gif'

# }# NOT RUN {
include_graphics2(gif_url, alt_path = png_url)
# }# NOT RUN {
# }