Ghost + LaTex

[rainyear]

Ghost v0.7.0

LaTex - MathJax v2.6.1

1. Code Injection

Add following codes to {{ghost_foot}} tag:

<script type="text/x-mathjax-config">
MathJax.Hub.Config({
  jax: ["input/TeX", "output/SVG"],
  tex2jax: {inlineMath: [['$$', '$$']],displayMath : [['$$$$','$$$$']]},
});
</script>
<script src="//cdn.bootcss.com/mathjax/2.6.1/MathJax.js?config=TeX-AMS_HTML"></script>

2. Escape a_i, b_i

$a_i, b_i$ like LaTex equations might be parsed into $a<em>i, b</em>i. We need a custom extension of Showdown to escape this transition:

cd $BLOG/core/server/models

# create new file
vim ghostLatex.js

(function () {
    var ghostLatex = function(){
        return [
            {
                type    : 'lang',
                filter : function (text) {
                    return text.replace(/([^\\\\])~D([^$]+[^\\])~D/g,  function(match, g1, g2) {
                        res = g1 + '~D' + g2.replace(/\\([^\d\w\s])/g, function (match, g) {
                            if (g == '\\')
                                g = '\\\\'
                            return '\\\\' + g;
                        }).replace(/_/g, '\\_').replace(/\*/g, '\\*') + '~D';
                        return res;
                    });
                }
            }
        ]
    };
    // Server-side export
    if (typeof module !== 'undefined') {
        module.exports = ghostLatex;
    }
}());

Edit $BLOG/core/server/models/post.js:

/* Add to the top */
var ghostLatex = require('./ghostLatex');
/* 
Update 
    converter      = new Showdown.converter({extensions: ['ghostgfm', 'footnotes', 'highlight']}),
to
*/
converter      = new Showdown.converter({extensions: [ghostLatex, 'ghostgfm', 'footnotes', 'highlight']}),

Only new posts will be affected after Ghost server is restarted, if you want to update all your published posts, you might need to edit and update them.

[rainyear]

Update:

This change could cause:

export PATH=$PATH:$JAVA_HOME

rendered as:

export PATH=$PATH:$JAVA\_HOME

So we should change code block back, add another filter:

{
        type: 'lang',
        filter: function(text) {
                return text.replace(/```([\s\S]*?\n)```/gim, function(match, g){
                        return "```" + g.replace(/\\_/g, '_') + "```";
                })
        }
}