codeslinger · July 25, 2010 23:13
diff --git a/formula_editor.rb b/formula_editor.rb
 #!/usr/bin/env ruby
 # vim:set ts=4 sw=4 et ai:
 #############################################################################
 # Copyright (c) 2007, Toby DiPasquale
 #
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without 
 # modification, are permitted provided that the following conditions are met:
 #
 #    * Redistributions of source code must retain the above copyright notice, 
 #      this list of conditions and the following disclaimer.
 #    * Redistributions in binary form must reproduce the above copyright 
 #      notice, this list of conditions and the following disclaimer in the 
 #      documentation and/or other materials provided with the distribution.
 #    * Neither the name of the Toby DiPasquale nor the names of his 
 #      contributors may be used to endorse or promote products derived from 
 #      this software without specific prior written permission.
 #
 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER 
 # OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 # PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 # PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 # LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #############################################################################
 #
 # Fancy Pants Formula Generator
 #
 # Web-based wrapper around LaTeX tools for easy creation of images with
 # mathematical equations in them for use with any app that supports images 
 # but does not natively have an equation editor (e.g. Apple Pages, 
 # SocialText, etc).
 # 
 # Last Modified: 2007.04.01
 #
 # Requires:
 #   Ruby            >= 1.8.2
 #   Ghostscript     >= 6.52
 #   NetPBM          >= 9.24
 #   teTeX           >= 3.0
 #
 # Inspired by John Walker's textogif 
 #  <http://www.fourmilab.ch/webtools/textogif/textogif.html>
 # 
 require 'webrick'
 require 'cgi'

 CLEANUP = "rm -f *.png"

 P = { :dpi => 150, :res => 1.0, :background => '', :transparent => 'ff/ff/ff' }

 CONVERT = [
    "echo x | latex %s",
    "dvips -f %s > %s",
    "echo quit | gs -q -dNOPAUSE -r%dx%d -sOutputFile=- -sDEVICE=pbmraw %s | pnmcrop -white | pnmdepth 255 | %s pnmscale %.3f | pnmtopng -interlace -transparent rgb:%s > %s",
    "rm -f *.tex *.dvi *.aux *.log *.ps",
    "pngtopnm %s | pnmfile"
 ]

 TEX_TEMPLATE = <<EOF
 \\documentclass[12pt]{article}
 \\pagestyle{empty}
 \\begin{document}

 \\begin{displaymath}
 %s
 \\end{displaymath}

 \\end{document}
 EOF

 FORM_TEMPLATE = <<EOF
 <html><head></head><body>
 <h2>Fancy Pants Formula Generator</h2>
 %s
 <form method="POST" action="/formula">
 <span>Enter LaTeX to convert to image of equation. <a href="http://cs.wlu.edu/~necaise/refs/latex2e/" target="_blank">LaTeX? Huh?</a></span><br/>
 <textarea id="formula" name="formula" cols="60" rows="10" />%s</textarea>
 <br/>
 <label for="dpi">DPI</label>
 %s
 <input id="submit" name="submit" type="submit" value="Generate" />
 </form>
 </body></html>
 EOF

 class FormulaService < WEBrick::HTTPServlet::AbstractServlet
 private
    def run_system cmd
        r = `#{cmd}`
        raise "command failed with status #{$?.exitstatus}: #{cmd}" unless $?.exitstatus.zero?
        r
    end
    
    def tempnam
        "#{Time.now.to_i}#{rand(1000000)}"
    end
    
    def generate_dpi_select default
        str = "<select id=\"dpi\" name=\"dpi\">\n"
        (50..1000).step(25) { |x| 
            str << "<option value=\"%d\" %s>%d</option>\n" % [x, (x == default) ? "selected" : "", x]
        }
        str << "</select>\n"
        str
    end

    def generate_image formula, dpi=P[:dpi]
        tmp = tempnam
        ps = tmp + ".ps"
        imgfile = tmp + ".png"
        File.open(tmp + ".tex", 'w') { |f| f.write(TEX_TEMPLATE % [formula]) }
        
        scale = (dpi / P[:res]).to_i
        run_system(CONVERT[0] % tmp)
        run_system(CONVERT[1] % [tmp, ps])
        run_system(CONVERT[2] % [scale, scale, ps, P[:background], P[:res], P[:transparent], imgfile])
        run_system(CONVERT[3])
        rv = run_system(CONVERT[4] % [imgfile])
        rv =~ /(\d+) by (\d+)/m
        width, height = $1, $2

        "<img src=\"%s\" height=\"%d\" width=\"%d\"/><br/><br/>" % [imgfile, height, width]
    end

    def generate_page dpi=P[:dpi], formula='', img=''
        FORM_TEMPLATE % [img, formula, generate_dpi_select(dpi)]
    end

 public
    def do_GET req, resp
        resp.body = generate_page
    end

    def do_POST req, resp
        if req.body.nil?
            resp.body = generate_page
        else
            parts = CGI.parse req.body
            formula, dpi = parts['formula'][0], parts['dpi'][0].to_i
            unless formula and dpi
                raise "invalid form submission; missing parameter!"
            end
            img = generate_image formula, dpi
            resp.body = generate_page dpi, formula, img
        end
    end
 end

 def start_webrick config={}
    config.update :Port => 10000
    server = WEBrick::HTTPServer.new config
    yield server if block_given?
    [ 'INT', 'TERM' ].each { |signal| 
        trap(signal) { 
            server.shutdown
            system(CLEANUP)
        } 
    }
    server.start
 end

 start_webrick do |server|
    server.mount '/', WEBrick::HTTPServlet::FileHandler, Dir.pwd
    server.mount '/formula', FormulaService
 end
	#!/usr/bin/env ruby
	# vim:set ts=4 sw=4 et ai:
	#############################################################################
	# Copyright (c) 2007, Toby DiPasquale
	#
	# All rights reserved.
	#
	# Redistribution and use in source and binary forms, with or without
	# modification, are permitted provided that the following conditions are met:
	#
	# * Redistributions of source code must retain the above copyright notice,
	# this list of conditions and the following disclaimer.
	# * Redistributions in binary form must reproduce the above copyright
	# notice, this list of conditions and the following disclaimer in the
	# documentation and/or other materials provided with the distribution.
	# * Neither the name of the Toby DiPasquale nor the names of his
	# contributors may be used to endorse or promote products derived from
	# this software without specific prior written permission.
	#
	# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
	# OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
	# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
	# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
	# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	#############################################################################
	#
	# Fancy Pants Formula Generator
	#
	# Web-based wrapper around LaTeX tools for easy creation of images with
	# mathematical equations in them for use with any app that supports images
	# but does not natively have an equation editor (e.g. Apple Pages,
	# SocialText, etc).
	#
	# Last Modified: 2007.04.01
	#
	# Requires:
	# Ruby >= 1.8.2
	# Ghostscript >= 6.52
	# NetPBM >= 9.24
	# teTeX >= 3.0
	#
	# Inspired by John Walker's textogif
	# <http://www.fourmilab.ch/webtools/textogif/textogif.html>
	#
	require 'webrick'
	require 'cgi'

	CLEANUP = "rm -f *.png"

	P = { :dpi => 150, :res => 1.0, :background => '', :transparent => 'ff/ff/ff' }

	CONVERT = [
	"echo x \| latex %s",
	"dvips -f %s > %s",
	"echo quit \| gs -q -dNOPAUSE -r%dx%d -sOutputFile=- -sDEVICE=pbmraw %s \| pnmcrop -white \| pnmdepth 255 \| %s pnmscale %.3f \| pnmtopng -interlace -transparent rgb:%s > %s",
	"rm -f .tex .dvi .aux .log *.ps",
	"pngtopnm %s \| pnmfile"
	]

	TEX_TEMPLATE = <<EOF
	\\documentclass[12pt]{article}
	\\pagestyle{empty}
	\\begin{document}

	\\begin{displaymath}
	%s
	\\end{displaymath}

	\\end{document}
	EOF

	FORM_TEMPLATE = <<EOF
	<html><head></head><body>
	<h2>Fancy Pants Formula Generator</h2>
	%s
	<form method="POST" action="/formula">
	<span>Enter LaTeX to convert to image of equation. <a href="http://cs.wlu.edu/~necaise/refs/latex2e/" target="_blank">LaTeX? Huh?</a></span><br/>
	<textarea id="formula" name="formula" cols="60" rows="10" />%s</textarea>
	<br/>
	<label for="dpi">DPI</label>
	%s
	<input id="submit" name="submit" type="submit" value="Generate" />
	</form>
	</body></html>
	EOF

	class FormulaService < WEBrick::HTTPServlet::AbstractServlet
	private
	def run_system cmd
	r = `#{cmd}`
	raise "command failed with status #{$?.exitstatus}: #{cmd}" unless $?.exitstatus.zero?
	r
	end

	def tempnam
	"#{Time.now.to_i}#{rand(1000000)}"
	end

	def generate_dpi_select default
	str = "<select id=\"dpi\" name=\"dpi\">\n"
	(50..1000).step(25) { \|x\|
	str << "<option value=\"%d\" %s>%d</option>\n" % [x, (x == default) ? "selected" : "", x]
	}
	str << "</select>\n"
	str
	end

	def generate_image formula, dpi=P[:dpi]
	tmp = tempnam
	ps = tmp + ".ps"
	imgfile = tmp + ".png"
	File.open(tmp + ".tex", 'w') { \|f\| f.write(TEX_TEMPLATE % [formula]) }

	scale = (dpi / P[:res]).to_i
	run_system(CONVERT[0] % tmp)
	run_system(CONVERT[1] % [tmp, ps])
	run_system(CONVERT[2] % [scale, scale, ps, P[:background], P[:res], P[:transparent], imgfile])
	run_system(CONVERT[3])
	rv = run_system(CONVERT[4] % [imgfile])
	rv =~ /(\d+) by (\d+)/m
	width, height = $1, $2

	"<img src=\"%s\" height=\"%d\" width=\"%d\"/><br/><br/>" % [imgfile, height, width]
	end

	def generate_page dpi=P[:dpi], formula='', img=''
	FORM_TEMPLATE % [img, formula, generate_dpi_select(dpi)]
	end

	public
	def do_GET req, resp
	resp.body = generate_page
	end

	def do_POST req, resp
	if req.body.nil?
	resp.body = generate_page
	else
	parts = CGI.parse req.body
	formula, dpi = parts['formula'][0], parts['dpi'][0].to_i
	unless formula and dpi
	raise "invalid form submission; missing parameter!"
	end
	img = generate_image formula, dpi
	resp.body = generate_page dpi, formula, img
	end
	end
	end

	def start_webrick config={}
	config.update :Port => 10000
	server = WEBrick::HTTPServer.new config
	yield server if block_given?
	[ 'INT', 'TERM' ].each { \|signal\|
	trap(signal) {
	server.shutdown
	system(CLEANUP)
	}
	}
	server.start
	end

	start_webrick do \|server\|
	server.mount '/', WEBrick::HTTPServlet::FileHandler, Dir.pwd
	server.mount '/formula', FormulaService
	end