Helper function for adding an image from the web

We can flexibly add a web image inside of a table with web_image() function. The function provides a convenient way to generate an HTML fragment with an image URL. Because this function is currently HTML-based, it is only useful for HTML table output. To use this function inside of data cells, it is recommended that the text_transform() function is used. With that function, we can specify which data cells to target and then include a web_image() call within the required user-defined function (for the fn argument). If we want to include an image in other places (e.g., in the header, within footnote text, etc.) we need to use web_image() within the html() helper function.

web_image(url, height = 30)

Arguments

url	A url that resolves to an image file.
height	The absolute height (px) of the image in the table cell.

Value

A character object with an HTML fragment that can be placed inside of a cell.

Details

By itself, the function creates an HTML image tag, so, the call web_image("http://some.web.site/image.png") evaluates to:

<img src=\"http://some.web.site/image.png\" style=\"height:30px;\">

where a height of 30px is a default height chosen to work well within the heights of most table rows.

Figures

Function ID

8-1

See also

Other Image Addition Functions: ggplot_image(), local_image(), test_image()

Examples

# Get the PNG-based logo for the R
# Project from an image URL
r_png_url <-
  "https://www.r-project.org/logo/Rlogo.png"

# Create a tibble that contains heights
# of an image in pixels (one column as a
# string, the other as numerical values),
# then, create a gt table; use the
# `text_transform()` function to insert
# the R logo PNG image with the various
# sizes
tab_1 <-
  dplyr::tibble(
    pixels = px(seq(10, 35, 5)),
    image = seq(10, 35, 5)
  ) %>%
  gt() %>%
  text_transform(
    locations = cells_body(vars(image)),
    fn = function(x) {
      web_image(
        url = r_png_url,
        height = as.numeric(x)
      )
    }
  )

# Get the SVG-based logo for the R
# Project from an image URL
r_svg_url <-
  "https://www.r-project.org/logo/Rlogo.svg"

# Create a tibble that contains heights
# of an image in pixels (one column as a
# string, the other as numerical values),
# then, create a gt table; use the
# `tab_header()` function to insert
# the R logo SVG image once in the title
# and five times in the subtitle
tab_2 <-
  dplyr::tibble(
    pixels = px(seq(10, 35, 5)),
    image = seq(10, 35, 5)
  ) %>%
  gt() %>%
  tab_header(
    title = html(
      "<strong>R Logo</strong>",
      web_image(
        url = r_svg_url,
        height = px(50)
      )
    ),
    subtitle = html(
      web_image(
        url = r_svg_url,
        height = px(12)
      ) %>%
        rep(5)
    )
  )