Merge pull request #377 from pipex/latex-align
[Fix] Inline latex formula alignment
This commit is contained in:
bootstraponline
@@ -352,8 +352,8 @@ inline with regular text. For example:
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In order to get the mathematical equations rendering to work, you need the following binaries:
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* LaText, TeTex or MacTex/BasicTeX (latex, dvips)
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* ImageMagick (convert)
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* LaTex, TeTex or MacTex/BasicTeX (pdflatex)
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* Netpbm (pnmcrop, pnmpad, pnmscale, ppmtopgm, pnmgamma, pnmtopng)
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* Ghostscript (gs)
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## SEQUENCE DIAGRAMS
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@@ -530,4 +530,4 @@ your changes merged back into core is as follows:
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$ git clone https://github.com/github/gollum.git
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$ cd gollum
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gollum$ rake build
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gollum$ gem install pkg/gollum*.gem
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gollum$ gem install pkg/gollum*.gem
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+16
-1
@@ -146,7 +146,22 @@ module Gollum
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def process_tex(data)
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@texmap.each do |id, spec|
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type, tex = *spec
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out = %{<img src="#{::File.join(@wiki.base_path, '_tex.png')}?type=#{type}&data=#{Base64.encode64(tex).chomp}" alt="#{CGI.escapeHTML(tex)}">}
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# Obtain the formula with parameters
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out = nil
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begin
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width, height, align, base64 = Gollum::Tex.render_formula(tex, true)
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# TODO: Should we load the binary inside the html?
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#out = %{<img width="#{width}" height="#{height}" style="vertical-align: #{align}px;" src="data:image/png;base64,\n#{base64}" alt="#{CGI.escapeHTML(tex)}" />}
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# Use the alignment values from the formula rendering but still use the call to '_tex.png'. Although it will call render_formula()
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# again, it will use the already cached formula and it might have some advantages from the point of view of browser caching (really not sure here).
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out = %{<img width="#{width}" height="#{height}" style="vertical-align: #{align}px;" src="#{::File.join(@wiki.base_path, '_tex.png')}?type=#{type}&data=#{Base64.encode64(tex).chomp}" alt="#{CGI.escapeHTML(tex)}" />}
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rescue # In case of error
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out = CGI.escapeHTML(tex)
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end
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data.gsub!(id, out)
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end
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data
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+322
-45
@@ -2,6 +2,7 @@ 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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require 'base64'
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module Gollum
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module Tex
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@@ -10,80 +11,356 @@ module Gollum
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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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\\documentclass[11pt]{article}
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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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\\setlength{\\topskip}{0pt}
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\\setlength{\\parindent}{0pt}
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\\setlength{\\abovedisplayskip}{0pt}
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\\setlength{\\belowdisplayskip}{0pt}
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\\usepackage{geometry}
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\\usepackage{amsfonts}
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\\usepackage{amsmath}
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\\newsavebox{\\snippetbox}
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\\newlength{\\snippetwidth}
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\\newlength{\\snippetheight}
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\\newlength{\\snippetdepth}
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\\newlength{\\pagewidth}
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\\newlength{\\pageheight}
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\\newlength{\\pagemargin}
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\\begin{lrbox}{\\snippetbox}%
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\$%s\$
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\\end{lrbox}
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\\settowidth{\\snippetwidth}{\\usebox{\\snippetbox}}
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\\settoheight{\\snippetheight}{\\usebox{\\snippetbox}}
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\\settodepth{\\snippetdepth}{\\usebox{\\snippetbox}}
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\\setlength\\pagemargin{4pt}
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\\setlength\\pagewidth\\snippetwidth
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\\addtolength\\pagewidth\\pagemargin
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\\addtolength\\pagewidth\\pagemargin
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\\setlength\\pageheight\\snippetheight
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\\addtolength{\\pageheight}{\\snippetdepth}
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\\addtolength\\pageheight\\pagemargin
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\\addtolength\\pageheight\\pagemargin
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\\newwrite\\foo
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\\immediate\\openout\\foo=\\jobname.dimensions
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\\immediate\\write\\foo{snippetdepth = \\the\\snippetdepth}
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\\immediate\\write\\foo{snippetheight = \\the\\snippetheight}
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\\immediate\\write\\foo{snippetwidth = \\the\\snippetwidth}
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\\immediate\\write\\foo{pagewidth = \\the\\pagewidth}
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\\immediate\\write\\foo{pageheight = \\the\\pageheight}
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\\immediate\\write\\foo{pagemargin = \\the\\pagemargin}
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\\closeout\\foo
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\\geometry{paperwidth=\\pagewidth,paperheight=\\pageheight,margin=\\pagemargin}
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\\begin{document}%
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\\usebox{\\snippetbox}%
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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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attr_accessor :latex_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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self.latex_path = 'pdflatex'
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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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if `which pdflatex` == ""
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raise Error, "`pdflatex` 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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if `which pnmcrop` == ""
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raise Error, "`pnmcrop` command not found"
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end
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if `which pnmpad` == ""
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raise Error, "`pnmpad` command not found"
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end
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if `which pnmscale` == ""
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raise Error, "`pnmscale` command not found"
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end
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if `which ppmtopgm` == ""
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raise Error, "`ppmtopgm` command not found"
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end
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if `which pnmgamma` == ""
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raise Error, "`pnmgamma` command not found"
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end
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if `which pnmtopng` == ""
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raise Error, "`pnmtopng` 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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# Render the formula and calculate the correct alignment
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# for the image in the html.
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#
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# This is a ruby implementation of the Perl version described
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# at http://tex.stackexchange.com/questions/44486/pixel-perfect-vertical-alignment-of-image-rendered-tex-snippets
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#
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# The main caveat is that rendering takes quite a bit of processing power,
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# which can make the page load slowly if it has to render each time.
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# For this reason, the method caches the rendered formula in `/tmp` for reduced
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# loading time in subsequent loads.
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#
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# @param formula the tex formula to render
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# @param with_properties, if true it returns an array with a base64
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# string with the image, and the alignment values for the image.
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# Otherwise it returns the binary image.
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def self.render_formula(formula, with_properties=false)
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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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render_antialias_bits = 4
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render_oversample = 4
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display_oversample = 4
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gamma = 0.3
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if !with_properties
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display_oversample = 1
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gamma = 0.5
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end
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::File.open(tex_path, 'w') { |f| f.write(Template % formula) }
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oversample = render_oversample * display_oversample
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render_dpi = 96*1.2 * 72.27/72 * oversample # This is 1850.112 dpi.
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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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# Cache rendered formula and returned cached version if it exists
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::File.read(png_path)
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end
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# First look for the .cache directory in the home folder
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cache_dir = ::File.expand_path("~/.cache")
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if not ::File.exists?(cache_dir) or not ::File.directory?(cache_dir)
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::Dir.mkdir(cache_dir)
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end
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# Check that the gollum directory exists inside the cache dir
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cache_dir = ::File.join(cache_dir, "gollum")
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if not ::File.exists?(cache_dir) or not ::File.directory?(cache_dir)
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::Dir.mkdir(cache_dir)
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end
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# Check for the formula in the cache dir
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hash = Digest::SHA1.hexdigest(formula)
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cache_file = ::File.join(cache_dir, "tex-#{hash}")
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if ::File.exists?(cache_file)
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width, height, align, base64 = ::File.open(cache_file, 'rb') { |io| io.read }.split(",")
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if with_properties
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return width, height, align, base64
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else
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return Base64.decode64(base64)
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end
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end
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Dir.mktmpdir('tex') do |path|
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file = ::File.join(path, "formula")
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# --- Write TeX source and compile to PDF.Write snippet into template
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::File.open(file + ".tex", 'w') { |f| f.write(Template % formula) }
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result = sh_chdir path, "pdflatex",
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"-halt-on-error",
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"-output-directory=#{path}",
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"-output-format=pdf",
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"#{file}.tex",
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">#{file}.err 2>&1"
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# --- Convert PDF to PNM using Ghostscript.
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sh "gs",
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"-q -dNOPAUSE -dBATCH",
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"-dTextAlphaBits=#{render_antialias_bits}",
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"-dGraphicsAlphaBits=#{render_antialias_bits}",
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"-r#{render_dpi}",
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"-sDEVICE=pnmraw",
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"-sOutputFile=#{file}.pnm",
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"#{file}.pdf"
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img_width, img_height = pnm_width_height(file + ".pnm")
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# --- Read dimensions file written by TeX during processing.
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#
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# Example of file contents:
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# snippetdepth = 6.50009pt
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# snippetheight = 13.53899pt
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# snippetwidth = 145.4777pt
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# pagewidth = 153.4777pt
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# pageheight = 28.03908pt
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# pagemargin = 4.0pt
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dimensions = {}
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::File.open(file + ".dimensions").readlines.each_with_index do |line, i|
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if line =~ /^(\S+)\s+=\s+(-?[0-9\.]+)pt$/
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dimensions[$1] = Float($2) / 72.27 * render_dpi
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else
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raise Error, "#{file}.dimensions: invalid line: #{i}"
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end
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end
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# --- Crop bottom, then measure how much was cropped.
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sh "pnmcrop -white -bottom #{file}.pnm >#{file}.bottomcrop.pnm"
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#raise Error, "`pnmcrop` command failed: #{result}" unless ::File.exist?(file + ".bottomcrop.pnm")
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img_width_bottomcrop, img_height_bottomcrop = pnm_width_height("#{file}.bottomcrop.pnm")
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bottomcrop = img_height - img_height_bottomcrop
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# --- Crop top and sides, then measure how much was cropped from the top.
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sh "pnmcrop -white #{file}.bottomcrop.pnm > #{file}.crop.pnm"
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#raise Error, "`pnmcrop` command failed: #{result}" unless ::File.exist?(file + ".crop.pnm")
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cropped_img_width, cropped_img_height = pnm_width_height("#{file}.crop.pnm")
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topcrop = img_height_bottomcrop - cropped_img_height
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# --- Pad image with specific values on all four sides, in preparation for
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# downsampling.
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# Calculate bottom padding.
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snippet_depth = Integer(dimensions["snippetdepth"] + dimensions["pagemargin"] + 0.5) - bottomcrop
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padded_snippet_depth = round_up(snippet_depth, oversample)
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increase_snippet_depth = padded_snippet_depth - snippet_depth
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bottom_padding = increase_snippet_depth
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# --- Next calculate top padding, which depends on bottom padding.
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padded_img_height = round_up(cropped_img_height + bottom_padding,
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oversample)
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top_padding = padded_img_height - (cropped_img_height + bottom_padding)
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# --- Calculate left and right side padding. Distribute padding evenly.
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padded_img_width = round_up(cropped_img_width, oversample)
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left_padding = Integer((padded_img_width - cropped_img_width) / 2.0)
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right_padding = (padded_img_width - cropped_img_width) - left_padding
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# --- Pad the final image.
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result = sh "pnmpad",
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"-white",
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"-bottom=#{bottom_padding}",
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"-top=#{top_padding}",
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"-left=#{left_padding}",
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"-right=#{right_padding}",
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"#{file}.crop.pnm",
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">#{file}.pad.pnm"
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# --- Sanity check of final size.
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final_pnm_width, final_pnm_height = pnm_width_height(file + ".pad.pnm")
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raise Error, "#{final_pnm_width} is not a multiple of #{oversample}" unless final_pnm_width % oversample == 0
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raise "#{final_pnm_height} is not a multiple of #{oversample}" unless final_pnm_height % oversample == 0
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# --- Convert PNM to PNG.
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final_png_width = final_pnm_width / render_oversample
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final_png_height = final_pnm_height / render_oversample
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result = sh "cat #{file}.pad.pnm",
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"| ppmtopgm",
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"| pnmscale -reduce #{render_oversample}",
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"| pnmgamma #{gamma}",
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"| pnmtopng -compression 9",
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"> #{file}.png"
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raise Error, "Conversion to png failed: #{result}" unless ::File.exist?(file + ".png")
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# Calculate html properties
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html_img_width = final_png_width / display_oversample
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html_img_height = final_png_height / display_oversample
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html_img_vertical_align = sprintf("%.0f", -padded_snippet_depth / oversample)
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png_data_base64 = Base64.encode64(::File.open("#{file}.png") { |io| io.read }).chomp
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::File.open(cache_file, 'w') { |f| f.write(%{#{html_img_width},#{html_img_height},#{html_img_vertical_align},#{png_data_base64}}) }
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if with_properties
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return html_img_width, html_img_height, html_img_vertical_align, png_data_base64
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else
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::File.read(file + ".png")
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end
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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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def self.sh_chdir(path, *args)
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origcommand = args * " "
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return if origcommand == ""
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command = origcommand
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command.gsub! /(["\\])/, "\\$1"
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command = %{/bin/sh -c "(#{command}) 2>&1"}
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pid = spawn command, :chdir => path
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result = Process::waitpid(pid)
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exit_value = Integer($? >> 8), signal_num = Integer($? & 127), dumped_core = Integer($? & 128)
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raise Error, "Failed #{result}: #{origcommand}. Exit value = #{exit_value}. Signal Num = #{signal_num}. Dumped core = #{dumped_core}" unless $?.success?
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return result
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end
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def self.sh(*args)
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origcommand = args * " "
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return if origcommand == ""
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command = origcommand
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command.gsub! /(["\\])/, "\\$1"
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command = %{/bin/sh -c "(#{command}) 2>&1"}
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pid = spawn command
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#pid = spawn *args
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result = Process::waitpid(pid)
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exit_value = $? >> 8, signal_num = $? & 127, dumped_core = $? & 128
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raise Error, "Failed #{result}: #{origcommand}. Exit value = #{exit_value}. Signal Num = #{signal_num}. Dumped core = #{dumped_core}" unless $?.success?
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return result
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end
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def self.round_up(num, mod)
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num + (num % mod == 0 ? 0 : (mod - (num % mod)))
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end
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def self.pnm_width_height(filename)
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raise Error, "#{filename} is not a .pnm file" if filename !~ /\.pnm$/
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width = nil, height = nil
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::File.open(filename) do |file|
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# Read first line
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line = file.gets
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begin
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line = file.gets # Read next line, skipping comments
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end while line && line =~ /^#/
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if line =~ /^(\d+)\s+(\d+)$/
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width = Integer($1)
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height = Integer($2)
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else
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raise Error, "#{filename}: couldn't read image size"
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end
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end
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raise Error, "#{filename}: couldn't read image size" unless width && height
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return width, height
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end
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end
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end
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+2
-2
@@ -605,13 +605,13 @@ end
|
||||
|
||||
test "TeX block syntax" do
|
||||
content = 'a \[ a^2 \] b'
|
||||
output = "<p>a<imgsrc=\"/_tex.png?type=block&data=YV4y\"alt=\"a^2\">b</p>"
|
||||
output = "<p>a<imgwidth=\"15\"height=\"16\"style=\"vertical-align:-1px;\"src=\"/_tex.png?type=block&data=YV4y\"alt=\"a^2\"/>b</p>"
|
||||
compare(content, output, 'md')
|
||||
end
|
||||
|
||||
test "TeX inline syntax" do
|
||||
content = 'a \( a^2 \) b'
|
||||
output = "<p>a<imgsrc=\"/_tex.png?type=inline&data=YV4y\"alt=\"a^2\">b</p>"
|
||||
output = "<p>a<imgwidth=\"15\"height=\"16\"style=\"vertical-align:-1px;\"src=\"/_tex.png?type=inline&data=YV4y\"alt=\"a^2\"/>b</p>"
|
||||
compare(content, output, 'md')
|
||||
end
|
||||
|
||||
|
||||
Reference in New Issue
Block a user