Turn R scripts into terminal screencasts
asciicast takes an R script and turns it into an asciinema cast. It can simulate typing, and records all terminal output in real time as it happens.
- Input is an R script, output is a v2 asciicast recording.
- Record all terminal output in real time, as it happens.
- Simulate typing in the commands, with a configurable, randomized speed.
- Alternatively, whole comment blocks or expressions can just appear on the screen.
- Convert casts to SVG images using svg-term. The package comes with its own svg-term bundle, no external dependencies are needed.
- Render a single frame of a cast as an SVG image.
- Configurable delay at the beginning, at the end and between paragraphs.
- HTML widget, to be used in Rmarkdown documents, e.g. in vignettes.
- Read casts from asciinema JSON files (version 2), or from https://asciinema.org directly.
- Special knitr engine to create R markdown files with ascii casts. See
the
asciicast-demovignette. - Create ascii casts in GitHub READMEs via animated SVG files. See an
example in
inst/examplesor theREADME.Rmdsource of the README file you are reading.
- asciicast works best in an UTF-8 locale. It also works well if all output is ASCII, but non-ASCII output might cause problems (#36).
You can install the released version of asciicast from CRAN:
install.packages("asciicast")See the inst/examples
directory
for these examples.
The input script:
print("Hello world!")The result:
Input script that uses asciicast itself:
#' Title: asciicast example recorded in asciicast
#' Empty_wait: 3
#' End_wait: 20
# An example for using asciicast, recorded in asciicast itself! #!
# First, save the R code you want to run, in a script file. #!
# The file can contain any code, including interactive code, #!
# as long as it is a syntactically valid R file. #!
# Second, perform the recording with the `record()` function. #!
# We are recording an example file now, that comes with the package. #!
src <- system.file("examples", "hello.R", package = "asciicast")
cast <- asciicast::record(src)
# `cast` is an `asciicast` object, which has some metadata and the #!
# recording itself: #!
cast
# You can write `cast` to a JSON file that can be played by any #!
# asciinema player. Or you can write it to an SVG file that can #!
# be embedded into a web page, or a GitHub README. #!
svg <- tempfile(fileext = ".svg")
asciicast::write_svg(cast, svg, window = TRUE)
Input script with errors:
#' End_wait: 20
# Demonstrate that errors are handled well
# Base R error
library("not-this-really")
traceback()
# callr errors are saved to `.Last.error`, including a stack trace
library(cli)
callr::r(function() library("another-failure"))
.Last.error
- asciinema: https://asciinema.org/
- The original terminal session recorder: https://github.com/asciinema/asciinema
- svg-term: https://github.com/marionebl/svg-term, https://github.com/marionebl/svg-term-cli
MIT @ RStudio