R/zzz.R

In cameronbracken/pgfSweave: Quality speedy graphics compilation and caching with Sweave

.onLoad <- function(lib, pkg) {
  req.version <- "2.10"  
  installed.version <- getOption('pgfversion')
  
  if(!is.null(installed.version))
    comparePGFVersions(installed.version, req.version)
  else
    requirePGFVersion(req.version) 
}

requirePGFVersion <- function(req.version="2.10"){
  
  texDir <- tempdir()
  cwd <- getwd()
  texFile <- 'test-for-pgf.tex'
  logFile <- 'test-for-pgf.log'
  
  dummy <- file.copy(
    system.file('misc',texFile,package='pgfSweave'),
    file.path(texDir,texFile))
  
  setwd(texDir)
  
    # requires tikzDevice to be loaded
  latexCmd <- getOption('tikzLatex')

  # Append the batchmode flag to increase LaTeX 
  # efficiency.
  latexCmd <- paste( latexCmd, '-interaction=batchmode',
    '-output-directory', texDir, texFile)

  # Run that
  silence <- system( latexCmd, intern=T, ignore.stderr=T)
  
  logContents <- readLines( logFile )

  # Recover width by finding the line containing
  # tikzTeXWidth in the logfile.
  match <- logContents[ grep('PGFVersion=', logContents) ]

  # if pgf is not available, compilation will stop before printing anything 
  # out and there will be no matches. 
  if( length(match) == 0 ) stop(paste("PGF >=",req.version,"is required to use pgfSweave"))

  # Remove all parts of the string besides the
  # number.
  version <- gsub('[=A-Za-z-]','',match)
  
  match <- strsplit(match,'=')[[1]][2]
  
  setwd(cwd)
  
  comparePGFVersions(version, req.version, match)

  options(pgfversion = version) 
}

comparePGFVersions <- function(version,req.version, alttxt = NULL){
  
  if(is.null(alttxt)) alttxt <- version
  
  if(compareVersion(version,req.version) < 0)
    packageStartupMessage(paste("PGF >=",req.version,
        "is required to use pgfSweave, you are using version",alttxt,
        "\n\tYou can use pgfSweave but you may not be able to compile",
        "\n\tdocuments produced by pgfSweave, please update if possible."))
  else
    packageStartupMessage(paste('pgfSweave: Using PGF Version',alttxt))
}