tex_preview {texPreview}

Render and Preview snippets of TeX in R Viewer

Description

input TeX script into the function and it renders a pdf and converts it an image which is sent to Viewer.

Usage

tex_preview(
  obj,
  tex_lines = NULL,
  stem = "tex_temp",
  overwrite = TRUE,
  keep_pdf = FALSE,
  tex_message = FALSE,
  fileDir = tex_opts$get("fileDir"),
  margin = tex_opts$get("margin"),
  imgFormat = tex_opts$get("imgFormat"),
  returnType = tex_opts$get("returnType"),
  resizebox = tex_opts$get("resizebox"),
  usrPackages = tex_opts$get("usrPackages"),
  engine = tex_opts$get("engine"),
  cleanup = tex_opts$get("cleanup"),
  density = tex_opts$get("density"),
  svg_max = tex_opts$get("svg_max"),
  print.xtable.opts = tex_opts$get("print.xtable.opts"),
  opts.html = tex_opts$get("opts.html"),
  markers = interactive(),
  ...
)

Arguments

obj

object to convert to TeX script

tex_lines

vector of character, in case of special needs, instead of asking texPreview to build up, you may choose to pass in the contents of the complete LaTeX file directly. It should be a vector of character with each element as a line of raw TeX code.

stem

character, name to use in output files, Default: "tex_temp"

overwrite

logical, controls if overwriting of output stem* files given their existences, Default: TRUE

keep_pdf

logical, controls if the rendered pdf file should be kept or deleted, Default: FALSE

tex_message

logical, controls if latex executing messages are displayed in console. Default: FALSE

fileDir

character, output destination. If NULL a temp.dir() will be used and no output will be saved, Default: tex_opts$get('fileDir')

margin

table margin for pdflatex call, Default: tex_opts$get('margin')

imgFormat

character, defines the type of image the PDF is converted to Default: tex_opts$get('imgFormat')

returnType

character, one of "viewer", "html", or "tex" determining appropriate return type for the rendering process, Default: tex_opts$get('returnType')

resizebox

logical, forces a tabular tex object to be constrained on the margins of the document, Default: tex_opts$get('resizebox')

usrPackages

character, vector of usepackage commands, see details for string format

engine

character, specifies which latex to pdf engine to use ('pdflatex','xelatex','lualatex'), Default: tex_opts$get('engine')

cleanup

character, vector of file extensions to clean up after building pdf, Default: tex_opts$get('cleanup')

density

numeric, controls the density of the image. Default is 150: tex_opts$get('density)

svg_max

numeric, maximum svg file size allowable to preview, Default: tex_opts$get('svg_max')

print.xtable.opts

list, contains arguments to pass to print.table, relevant only if xtable is used as the input, Default: tex_opts$get('print.xtable.opts')

opts.html

list, html options, Default: tex_opts$get('opts.html')

markers

logical, if TRUE then RStudio markers will be invoked to create links for the log file on rendering errors, Default: interactive()

...

passed to system2

Details

tex_preview is an ⁠S3 method⁠ that can be used to preview TeX output from different object classes.

Built-in support includes:

• character (tex lines)

• knitr_kable (kable/kableExtra)

• xtable

• texreg

• equatiomatic

System Requirements

The function assumes the system has pdflatex installed and it is defined in the PATH.

TeX Packages

To add packages to the tex file on render there are two options

• Use build_usepackage and use the input argument usrPackages.

• Append to the input object ⁠\\usepackage{...}⁠ calls, they will be parsed and added the to rendering.

Images

• An image file of the name stem with the extension specified in imgFormat.

• The default extension is png.

Side effects

• The function writes two files to disk in the fileDir

  • Image file

  • TeX script

• The rendering files are removed up from the fileDir. This can be controlled using the cleanup argument or tex_opts$get('cleanup')

Value

The output of the function is dependent on the value of returnType:

• viewer: NULL

  • magick image is printed in the internal viewer

• tex:

  • character, TeX lines

  • printed 'asis' in RMarkdown

• input: character

  • path to the file containing the tex wrapped in an input call

  • printed 'asis' in RMarkdown

• html: magick image

  • Printed as an HTML document in the internal viewer

  • Printed as an image in RMarkdown

Examples

data('iris')
if(interactive()){

# Raw TeX

tex <- '\\begin{tabular}{llr}
\\hline
\\multicolumn{2}{c}{Item} \\\\
\\cline{1-2}
Animal    & Description & Price (\\$) \\\\
\\hline
Gnat      & per gram    & 13.65      \\\\
& each        & 0.01       \\\\
Gnu       & stuffed     & 92.50      \\\\
Emu       & stuffed     & 33.33      \\\\
Armadillo & frozen      & 8.99       \\\\
\\hline
\\end{tabular}'

# knitr kable

 mtcars |>
   head() |>
   knitr::kable("latex") |>
   tex_preview()

# with svg output pan/zoom is enabled in the internal viewer

tex_preview(obj = tex,stem = 'eq',imgFormat = 'svg')

# use tex_lines parameter to pass full document

tikz_path <- system.file(
                  'examples/tikz/credit_rationing.tex',
                  package = 'texPreview'
                  )

tex_preview(tex_lines = readLines(tikz_path))

}