Plot a mermaid diagram — mermaid • airGRiwrm

These functions download the diagram from https://mermaid.ink which generates the image.

mermaid(
  diagram,
  format = "png",
  theme = "default",
  dir.dest = tempdir(),
  file.dest = paste0(rlang::hash(link), ".", format),
  server = Sys.getenv("MERMAID_URL", "https://mermaid.ink"),
  link = mermaid_gen_link(diagram, theme = theme, format = format, server = server)
)

mermaid_gen_link(
  diagram,
  theme = "default",
  format = "png",
  server = Sys.getenv("MERMAID_URL", "https://mermaid.ink")
)

# S3 method for class 'mermaid'
plot(x, add = FALSE, ...)

Arguments

diagram: Diagram in mermaid markdown-like language or file (as a connection or file name) containing a diagram specification
format: Image format (either "jpg", or "png", or "svg")
theme: Mermaid theme (See available themes in Mermaid documentation)
dir.dest: Destination folder for the downloaded image. This parameter is ignored if file.dest contains a folder path.
file.dest: Path to the downloaded image. It's combined with dir.dest if it only contains the name of the file without a folder path.
server: URL of the server used to generate the link
link: Link generated by mermaid_gen_link
x: character mermaid diagram dialect
add: logical to add the diagram on the existing plot
...: Other argument passed to mermaid

Value

mermaid returns the path to the downloaded image or NA if the download failed. In this latter case, get the error message in the attribute "error".
mermaid_gen_link returns the link to the web service which generates the diagram
plot.mermaid produces a R plot with the mermaid diagram

Nothing, used for side effect.

Details

Compared to the diagrammeR::mermaid function, the generated image or plot is not a HTMLwidget and can be knit in pdf through latex and moreover, its size can be controlled with fig.width and fig.height.

If the generation failed (due to internet connection failure or syntax error in mermaid script), the functions raises no error (see mermaid returned value).

By default, mermaid uses the service https://mermaid.ink. One can define an alternative server to use with the environment variable MERMAID_URL.

Examples

diagram <- "flowchart LR\n  A --> B"
mermaid_gen_link(diagram)
#> [1] "https://mermaid.ink/img/pako:eNqrVkrOT0lVslJKy8kvT85ILCpR8AmKyVNQcFTQ1bVTcFLSUcpNLcpNzExRsqpWKslIzQUpTklNSyzNKVGqrQUAjIcUfg?type=png"
# \dontrun{
f <- mermaid(diagram)
#> Warning: URL 'https://mermaid.ink/img/pako:eNqrVkrOT0lVslJKy8kvT85ILCpR8AmKyVNQcFTQ1bVTcFLSUcpNLcpNzExRsqpWKslIzQUpTklNSyzNKVGqrQUAjIcUfg?type=png': Timeout of 60 seconds was reached
f
#> [1] NA
#> attr(,"error")
#> [1] "cannot open URL 'https://mermaid.ink/img/pako:eNqrVkrOT0lVslJKy8kvT85ILCpR8AmKyVNQcFTQ1bVTcFLSUcpNLcpNzExRsqpWKslIzQUpTklNSyzNKVGqrQUAjIcUfg?type=png'"

# For displaying the diagram in Rmarkdown document
knitr::include_graphics(mermaid(diagram))
#> Warning: URL 'https://mermaid.ink/img/pako:eNqrVkrOT0lVslJKy8kvT85ILCpR8AmKyVNQcFTQ1bVTcFLSUcpNLcpNzExRsqpWKslIzQUpTklNSyzNKVGqrQUAjIcUfg?type=png': Timeout of 60 seconds was reached
#> Error in Encoding(x): a character vector argument expected

# Clean temporary folder
unlink(f)
# }

# \dontrun{
s <- "flowchart LR
A --> B"
class(s) <- c("mermaid", class(s))
plot(s)
#> Warning: URL 'https://mermaid.ink/img/pako:eNqrVkrOT0lVslJKy8kvT85ILCpR8AmKyXNU0NW1U3BS0lHKTS3KTcxMUbKqVirJSM0FKU1JTUsszSlRqq0FAHJVFD4?type=png': Timeout of 60 seconds was reached
#> Warning: Mermaid diagram generation failed with error:
#> cannot open URL 'https://mermaid.ink/img/pako:eNqrVkrOT0lVslJKy8kvT85ILCpR8AmKyXNU0NW1U3BS0lHKTS3KTcxMUbKqVirJSM0FKU1JTUsszSlRqq0FAHJVFD4?type=png'
# }