Joshua Peek
90 lines
2.1 KiB
Ruby
90 lines
2.1 KiB
Ruby
require 'fileutils'
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require 'shellwords'
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require 'tmpdir'
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require 'posix/spawn'
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module Gollum
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module Tex
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class Error < StandardError; end
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extend POSIX::Spawn
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Template = <<-EOS
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\\documentclass[12pt]{article}
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\\usepackage{color}
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\\usepackage[dvips]{graphicx}
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\\pagestyle{empty}
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\\pagecolor{white}
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\\begin{document}
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{\\color{black}
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\\begin{eqnarray*}
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%s
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\\end{eqnarray*}}
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\\end{document}
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EOS
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class << self
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attr_accessor :latex_path, :dvips_path, :convert_path
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end
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self.latex_path = 'latex'
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self.dvips_path = 'dvips'
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self.convert_path = 'convert'
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def self.check_dependencies!
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return if @dependencies_available
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if `which latex` == ""
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raise Error, "`latex` command not found"
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end
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if `which dvips` == ""
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raise Error, "`dvips` command not found"
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end
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if `which convert` == ""
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raise Error, "`convert` command not found"
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end
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if `which gs` == ""
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raise Error, "`gs` command not found"
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end
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@dependencies_available = true
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end
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def self.render_formula(formula)
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check_dependencies!
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Dir.mktmpdir('tex') do |path|
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tex_path = ::File.join(path, 'formula.tex')
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dvi_path = ::File.join(path, 'formula.dvi')
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eps_path = ::File.join(path, 'formula.eps')
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png_path = ::File.join(path, 'formula.png')
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::File.open(tex_path, 'w') { |f| f.write(Template % formula) }
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result = sh latex_path, '-interaction=batchmode', 'formula.tex', :chdir => path
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raise Error, "`latex` command failed: #{result}" unless ::File.exist?(dvi_path)
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result = sh dvips_path, '-o', eps_path, '-E', dvi_path
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raise Error, "`dvips` command failed: #{result}" unless ::File.exist?(eps_path)
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result = sh convert_path, '+adjoin',
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'-antialias',
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'-transparent', 'white',
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'-density', '150x150',
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eps_path, png_path
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raise Error, "`convert` command failed: #{result}" unless ::File.exist?(png_path)
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::File.read(png_path)
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end
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end
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private
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def self.sh(*args)
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pid = spawn *args
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Process::waitpid(pid)
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end
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end
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end
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