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Convert a ggplot2 object to a base64-encoded PNG string

Source: R/utils.R
rdesk_plot_to_base64.Rd

Renders a ggplot2 object to a temporary PNG file and returns the result as a Base64-encoded data URI string (data:image/png;base64,...). This format can be assigned directly to an <img> tag src attribute in the JavaScript frontend via app$send().

If ggplot2 is not installed, the function stops with a helpful message. If rendering fails, a fallback error plot is returned instead of NULL.

Usage

rdesk_plot_to_base64(plot, width = 6, height = 4, dpi = 96)

Arguments

plot

A ggplot2 object to render.

width

Width of the rendered image in inches. Default 6.

height

Height of the rendered image in inches. Default 4.

dpi

Dots per inch resolution. Default 96.

Value

A single-element character string containing the data URI, or the output of rdesk_error_plot() if rendering fails.

See also

rdesk_error_plot() for the fallback error plot.

Examples

if (requireNamespace("ggplot2", quietly = TRUE)) {
  p <- ggplot2::ggplot(mtcars, ggplot2::aes(wt, mpg)) +
       ggplot2::geom_point()
  b64 <- rdesk_plot_to_base64(p)
  stopifnot(grepl("^data:image/png;base64,", b64))
}