showdown/src/subParsers/images.js

/**
 * Created by Estevao on 11-01-2015.
 */


/**
 * Turn Markdown image shortcuts into <img> tags.
 */
showdown.subParser('images', function (text, options, globals) {
    'use strict';

    var writeImageTag = function (wholeMatch, m1, m2, m3, m4, m5, m6, m7) {

        wholeMatch = m1;
        var altText = m2,
            linkId = m3.toLowerCase(),
            url = m4,
            title = m7,
            gUrls = globals.gUrls,
            gTitles = globals.gTitles;

        if (!title) {
            title = '';
        }

        if (url === '' || url === null) {
            if (linkId === '' || linkId === null) {
                // lower-case and turn embedded newlines into spaces
                linkId = altText.toLowerCase().replace(/ ?\n/g, ' ');
            }
            url = '#' + linkId;

            if (typeof gUrls[linkId] !== 'undefined') {
                url = gUrls[linkId];
                if (typeof gTitles[linkId] !== 'undefined') {
                    title = gTitles[linkId];
                }
            }
            else {
                return wholeMatch;
            }
        }

        altText = altText.replace(/"/g, '&quot;');
        url = showdown.helper.escapeCharacters(url, '*_');
        var result = '<img src="' + url + '" alt="' + altText + '"';

        // attacklab: Markdown.pl adds empty title attributes to images.
        // Replicate this bug.

        //if (title != "") {
        title = title.replace(/"/g, '&quot;');
        title = escapeCharacters(title, '*_');
        result += ' title="' + title + '"';
        //}

        result += ' />';

        return result;
    };


    // First, handle reference-style labeled images: ![alt text][id]
    /*
     text = text.replace(/
     (						// wrap whole match in $1
     !\[
     (.*?)				// alt text = $2
     \]

     [ ]?				// one optional space
     (?:\n[ ]*)?			// one optional newline followed by spaces

     \[
     (.*?)				// id = $3
     \]
     )()()()()				// pad rest of backreferences
     /g,writeImageTag);
     */
    text = text.replace(/(!\[(.*?)\][ ]?(?:\n[ ]*)?\[(.*?)\])()()()()/g, writeImageTag);

    // Next, handle inline images:  ![alt text](url "optional title")
    // Don't forget: encode * and _
    /*
     text = text.replace(/
     (						// wrap whole match in $1
     !\[
     (.*?)				// alt text = $2
     \]
     \s?					// One optional whitespace character
     \(					// literal paren
     [ \t]*
     ()					// no id, so leave $3 empty
     <?(\S+?)>?			// src url = $4
     [ \t]*
     (					// $5
     (['"])			// quote char = $6
     (.*?)			// title = $7
     \6				// matching quote
     [ \t]*
     )?					// title is optional
     \)
     )
     /g,writeImageTag);
     */
    text = text.replace(/(!\[(.*?)\]\s?\([ \t]*()<?(\S+?)>?[ \t]*((['"])(.*?)\6[ \t]*)?\))/g, writeImageTag);

    return text;
});