Class: LatexToPdf

Inherits:
Object
  • Object
show all
Defined in:
lib/rails-latex/latex_to_pdf.rb

Class Method Summary collapse

Class Method Details

.config ⇒ Object 



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# File 'lib/rails-latex/latex_to_pdf.rb', line 3

def self.config
  @config||={:command => 'pdflatex', :arguments => ['-halt-on-error'], :parse_twice => false, :parse_runs => 1}
end

.escape_latex(text) ⇒ Object

Escapes LaTex special characters in text so that they wont be interpreted as LaTex commands.

This method will use RedCloth to do the escaping if available.



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# File 'lib/rails-latex/latex_to_pdf.rb', line 61

def self.escape_latex(text)
  # :stopdoc:
  unless @latex_escaper
    if defined?(RedCloth::Formatters::LATEX)
      class << (@latex_escaper=RedCloth.new(''))
        include RedCloth::Formatters::LATEX
      end
    else
      class << (@latex_escaper=Object.new)
        ESCAPE_RE=/([{}_$&%#])|([\\^~|<>])/
        ESC_MAP={
          '\\' => 'backslash',
          '^' => 'asciicircum',
          '~' => 'asciitilde',
          '|' => 'bar',
          '<' => 'less',
          '>' => 'greater',
        }

        def latex_esc(text)   # :nodoc:
          text.gsub(ESCAPE_RE) {|m|
            if $1
              "\\#{m}"
            else
              "\\text#{ESC_MAP[m]}{}"
            end
          }
        end
      end
    end
    # :startdoc:
  end

  @latex_escaper.latex_esc(text.to_s).html_safe
end

.generate_pdf(code, config, parse_twice = nil) ⇒ Object

Converts a string of LaTeX code into a binary string of PDF.

pdflatex is used to convert the file and creates the directory #{Rails.root}/tmp/rails-latex/ to store intermediate files.

The config argument defaults to LatexToPdf.config but can be overridden using @latex_config.

The parse_twice argument and using config is deprecated in favor of using config instead.



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# File 'lib/rails-latex/latex_to_pdf.rb', line 15

def self.generate_pdf(code,config,parse_twice=nil)
  config=self.config.merge(config)
  parse_twice=config[:parse_twice] if parse_twice.nil? # deprecated
  parse_runs=[config[:parse_runs], (parse_twice ? 2 : config[:parse_runs])].max
  Rails.logger.info "Running Latex #{parse_runs} times..."
  dir=File.join(Rails.root,'tmp','rails-latex',"#{Process.pid}-#{Thread.current.hash}")
  input=File.join(dir,'input.tex')
  FileUtils.mkdir_p(dir)
  # copy any additional supporting files (.cls, .sty, ...)
  supporting = config[:supporting]
  if supporting.kind_of?(String) or supporting.kind_of?(Pathname) or (supporting.kind_of?(Array) and supporting.length > 0)
    FileUtils.cp_r(supporting, dir)
  end
  File.open(input,'wb') {|io| io.write(code) }
  Process.waitpid(
    fork do
      begin
        Dir.chdir dir
        args=config[:arguments] + %w[-shell-escape -interaction batchmode input.tex]
        kwargs={:out => ["input.log","a"]}
        (parse_runs-1).times do
          system config[:command],'-draftmode',*args,**kwargs
        end
        exec config[:command],*args,**kwargs
      rescue
        File.open("input.log",'a') {|io|
          io.write("#{$!.message}:\n#{$!.backtrace.join("\n")}\n")
        }
      ensure
        Process.exit! 1
      end
    end)
  if File.exist?(pdf_file=input.sub(/\.tex$/,'.pdf'))
    FileUtils.mv(input,File.join(dir,'..','input.tex'))
    FileUtils.mv(input.sub(/\.tex$/,'.log'),File.join(dir,'..','input.log'))
    result=File.read(pdf_file)
    FileUtils.rm_rf(dir)
  else
    raise "pdflatex failed: See #{input.sub(/\.tex$/,'.log')} for details"
  end
  result
end