We can flexibly add a local image (i.e., an image residing on disk) inside of
a table with local_image() function. The function provides a convenient way
to generate an HTML fragment using an on-disk PNG or SVG. 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 local_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 local_image() within the html() helper function.
local_image(filename, height = 30)
Arguments
| filename | A path 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 with an image URI embedded
within. We can easily experiment with a local PNG or SVG image that's
available in the gt package using the test_image() function. Using
that, the call local_image(file = test_image(type = "png")) evaluates to:
<img cid=<random CID> src=<data URI> 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
8-2
See also
Other Image Addition Functions:
ggplot_image(),
test_image(),
web_image()
Examples
# 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 # a local test image (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) { local_image( filename = test_image(type = "png"), height = as.numeric(x) ) } )