helpers.js

/*

StackBlur - a fast almost Gaussian Blur For Canvas

Version:    0.5
Author:     Mario Klingemann
Contact:    mario@quasimondo.com
Website:    http://www.quasimondo.com/StackBlurForCanvas
Twitter:    @quasimondo

In case you find this class useful - especially in commercial projects -
I am not totally unhappy for a small donation to my PayPal account
mario@quasimondo.de

Or support me on flattr:
https://flattr.com/thing/72791/StackBlur-a-fast-almost-Gaussian-Blur-Effect-for-CanvasJavascript

Copyright (c) 2010 Mario Klingemann

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.
*/

var mul_table = [
        512,512,456,512,328,456,335,512,405,328,271,456,388,335,292,512,
        454,405,364,328,298,271,496,456,420,388,360,335,312,292,273,512,
        482,454,428,405,383,364,345,328,312,298,284,271,259,496,475,456,
        437,420,404,388,374,360,347,335,323,312,302,292,282,273,265,512,
        497,482,468,454,441,428,417,405,394,383,373,364,354,345,337,328,
        320,312,305,298,291,284,278,271,265,259,507,496,485,475,465,456,
        446,437,428,420,412,404,396,388,381,374,367,360,354,347,341,335,
        329,323,318,312,307,302,297,292,287,282,278,273,269,265,261,512,
        505,497,489,482,475,468,461,454,447,441,435,428,422,417,411,405,
        399,394,389,383,378,373,368,364,359,354,350,345,341,337,332,328,
        324,320,316,312,309,305,301,298,294,291,287,284,281,278,274,271,
        268,265,262,259,257,507,501,496,491,485,480,475,470,465,460,456,
        451,446,442,437,433,428,424,420,416,412,408,404,400,396,392,388,
        385,381,377,374,370,367,363,360,357,354,350,347,344,341,338,335,
        332,329,326,323,320,318,315,312,310,307,304,302,299,297,294,292,
        289,287,285,282,280,278,275,273,271,269,267,265,263,261,259];


var shg_table = [
         9, 11, 12, 13, 13, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17,
        17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 18, 18, 18, 19,
        19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 20, 20, 20,
        20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 21,
        21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21,
        21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22,
        22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22,
        22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 23,
        23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
        23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
        23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
        23, 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
        24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
        24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
        24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
        24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24 ];


function stackBlurCanvasRGB( context, top_x, top_y, width, height, radius )
{
    if ( isNaN(radius) || radius < 1 ) return;
    radius |= 0;

    var imageData;

    try {
      try {
        imageData = context.getImageData( top_x, top_y, width, height );
      } catch(e) {

        // NOTE: this part is supposedly only needed if you want to work with local files
        // so it might be okay to remove the whole try/catch block and just use
        // imageData = context.getImageData( top_x, top_y, width, height );
        try {
            netscape.security.PrivilegeManager.enablePrivilege("UniversalBrowserRead");
            imageData = context.getImageData( top_x, top_y, width, height );
        } catch(e) {
            alert("Cannot access local image");
            throw new Error("unable to access local image data: " + e);
            return;
        }
      }
    } catch(e) {
      alert("Cannot access image");
      throw new Error("unable to access image data: " + e);
    }

    var pixels = imageData.data;

    var x, y, i, p, yp, yi, yw, r_sum, g_sum, b_sum,
    r_out_sum, g_out_sum, b_out_sum,
    r_in_sum, g_in_sum, b_in_sum,
    pr, pg, pb, rbs;

    var div = radius + radius + 1;
    var w4 = width << 2;
    var widthMinus1  = width - 1;
    var heightMinus1 = height - 1;
    var radiusPlus1  = radius + 1;
    var sumFactor = radiusPlus1 * ( radiusPlus1 + 1 ) / 2;

    var stackStart = new BlurStack();
    var stack = stackStart;
    for ( i = 1; i < div; i++ )
    {
        stack = stack.next = new BlurStack();
        if ( i == radiusPlus1 ) var stackEnd = stack;
    }
    stack.next = stackStart;
    var stackIn = null;
    var stackOut = null;

    yw = yi = 0;

    var mul_sum = mul_table[radius];
    var shg_sum = shg_table[radius];

    for ( y = 0; y < height; y++ )
    {
        r_in_sum = g_in_sum = b_in_sum = r_sum = g_sum = b_sum = 0;

        r_out_sum = radiusPlus1 * ( pr = pixels[yi] );
        g_out_sum = radiusPlus1 * ( pg = pixels[yi+1] );
        b_out_sum = radiusPlus1 * ( pb = pixels[yi+2] );

        r_sum += sumFactor * pr;
        g_sum += sumFactor * pg;
        b_sum += sumFactor * pb;

        stack = stackStart;

        for( i = 0; i < radiusPlus1; i++ )
        {
            stack.r = pr;
            stack.g = pg;
            stack.b = pb;
            stack = stack.next;
        }

        for( i = 1; i < radiusPlus1; i++ )
        {
            p = yi + (( widthMinus1 < i ? widthMinus1 : i ) << 2 );
            r_sum += ( stack.r = ( pr = pixels[p])) * ( rbs = radiusPlus1 - i );
            g_sum += ( stack.g = ( pg = pixels[p+1])) * rbs;
            b_sum += ( stack.b = ( pb = pixels[p+2])) * rbs;

            r_in_sum += pr;
            g_in_sum += pg;
            b_in_sum += pb;

            stack = stack.next;
        }


        stackIn = stackStart;
        stackOut = stackEnd;
        for ( x = 0; x < width; x++ )
        {
            pixels[yi]   = (r_sum * mul_sum) >> shg_sum;
            pixels[yi+1] = (g_sum * mul_sum) >> shg_sum;
            pixels[yi+2] = (b_sum * mul_sum) >> shg_sum;

            r_sum -= r_out_sum;
            g_sum -= g_out_sum;
            b_sum -= b_out_sum;

            r_out_sum -= stackIn.r;
            g_out_sum -= stackIn.g;
            b_out_sum -= stackIn.b;

            p =  ( yw + ( ( p = x + radius + 1 ) < widthMinus1 ? p : widthMinus1 ) ) << 2;

            r_in_sum += ( stackIn.r = pixels[p]);
            g_in_sum += ( stackIn.g = pixels[p+1]);
            b_in_sum += ( stackIn.b = pixels[p+2]);

            r_sum += r_in_sum;
            g_sum += g_in_sum;
            b_sum += b_in_sum;

            stackIn = stackIn.next;

            r_out_sum += ( pr = stackOut.r );
            g_out_sum += ( pg = stackOut.g );
            b_out_sum += ( pb = stackOut.b );

            r_in_sum -= pr;
            g_in_sum -= pg;
            b_in_sum -= pb;

            stackOut = stackOut.next;

            yi += 4;
        }
        yw += width;
    }


    for ( x = 0; x < width; x++ )
    {
        g_in_sum = b_in_sum = r_in_sum = g_sum = b_sum = r_sum = 0;

        yi = x << 2;
        r_out_sum = radiusPlus1 * ( pr = pixels[yi]);
        g_out_sum = radiusPlus1 * ( pg = pixels[yi+1]);
        b_out_sum = radiusPlus1 * ( pb = pixels[yi+2]);

        r_sum += sumFactor * pr;
        g_sum += sumFactor * pg;
        b_sum += sumFactor * pb;

        stack = stackStart;

        for( i = 0; i < radiusPlus1; i++ )
        {
            stack.r = pr;
            stack.g = pg;
            stack.b = pb;
            stack = stack.next;
        }

        yp = width;

        for( i = 1; i <= radius; i++ )
        {
            yi = ( yp + x ) << 2;

            r_sum += ( stack.r = ( pr = pixels[yi])) * ( rbs = radiusPlus1 - i );
            g_sum += ( stack.g = ( pg = pixels[yi+1])) * rbs;
            b_sum += ( stack.b = ( pb = pixels[yi+2])) * rbs;

            r_in_sum += pr;
            g_in_sum += pg;
            b_in_sum += pb;

            stack = stack.next;

            if( i < heightMinus1 )
            {
                yp += width;
            }
        }

        yi = x;
        stackIn = stackStart;
        stackOut = stackEnd;
        for ( y = 0; y < height; y++ )
        {
            p = yi << 2;
            pixels[p]   = (r_sum * mul_sum) >> shg_sum;
            pixels[p+1] = (g_sum * mul_sum) >> shg_sum;
            pixels[p+2] = (b_sum * mul_sum) >> shg_sum;

            r_sum -= r_out_sum;
            g_sum -= g_out_sum;
            b_sum -= b_out_sum;

            r_out_sum -= stackIn.r;
            g_out_sum -= stackIn.g;
            b_out_sum -= stackIn.b;

            p = ( x + (( ( p = y + radiusPlus1) < heightMinus1 ? p : heightMinus1 ) * width )) << 2;

            r_sum += ( r_in_sum += ( stackIn.r = pixels[p]));
            g_sum += ( g_in_sum += ( stackIn.g = pixels[p+1]));
            b_sum += ( b_in_sum += ( stackIn.b = pixels[p+2]));

            stackIn = stackIn.next;

            r_out_sum += ( pr = stackOut.r );
            g_out_sum += ( pg = stackOut.g );
            b_out_sum += ( pb = stackOut.b );

            r_in_sum -= pr;
            g_in_sum -= pg;
            b_in_sum -= pb;

            stackOut = stackOut.next;

            yi += width;
        }
    }

    context.putImageData( imageData, top_x, top_y );

}

function BlurStack()
{
    this.r = 0;
    this.g = 0;
    this.b = 0;
    this.a = 0;
    this.next = null;
}

function dataURL2Blob(dataURL) {
    var BASE64_MARKER = ';base64,';
    if (dataURL.indexOf(BASE64_MARKER) == -1) {
      var parts = dataURL.split(',');
      var contentType = parts[0].split(':')[1];
      var raw = decodeURIComponent(parts[1]);

      return new Blob([raw], {type: contentType});
    }

    var parts = dataURL.split(BASE64_MARKER);
    var contentType = parts[0].split(':')[1];
    var raw = window.atob(parts[1]);
    var rawLength = raw.length;

    var uInt8Array = new Uint8Array(rawLength);

    for (var i = 0; i < rawLength; ++i) {
      uInt8Array[i] = raw.charCodeAt(i);
    }

    return new Blob([uInt8Array], {type: contentType});
}

function blob2dataURL(blob, callback) {
  var fr = new FileReader();
  fr.readAsDataURL(blob);
  fr.onloadend = function() {
    callback(fr.result);
  }

}


/**
 * marked - a markdown parser
 * Copyright (c) 2011-2014, Christopher Jeffrey. (MIT Licensed)
 * https://github.com/chjj/marked
 */

;(function() {

/**
 * Block-Level Grammar
 */

var block = {
  newline: /^\n+/,
  code: /^( {4}[^\n]+\n*)+/,
  fences: noop,
  hr: /^( *[-*_]){3,} *(?:\n+|$)/,
  heading: /^ *(#{1,6}) *([^\n]+?) *#* *(?:\n+|$)/,
  nptable: noop,
  lheading: /^([^\n]+)\n *(=|-){2,} *(?:\n+|$)/,
  blockquote: /^( *>[^\n]+(\n(?!def)[^\n]+)*\n*)+/,
  list: /^( *)(bull) [\s\S]+?(?:hr|def|\n{2,}(?! )(?!\1bull )\n*|\s*$)/,
  html: /^ *(?:comment *(?:\n|\s*$)|closed *(?:\n{2,}|\s*$)|closing *(?:\n{2,}|\s*$))/,
  def: /^ *\[([^\]]+)\]: *<?([^\s>]+)>?(?: +["(]([^\n]+)[")])? *(?:\n+|$)/,
  table: noop,
  paragraph: /^((?:[^\n]+\n?(?!hr|heading|lheading|blockquote|tag|def))+)\n*/,
  text: /^[^\n]+/
};

block.bullet = /(?:[*+-]|\d+\.)/;
block.item = /^( *)(bull) [^\n]*(?:\n(?!\1bull )[^\n]*)*/;
block.item = replace(block.item, 'gm')
  (/bull/g, block.bullet)
  ();

block.list = replace(block.list)
  (/bull/g, block.bullet)
  ('hr', '\\n+(?=\\1?(?:[-*_] *){3,}(?:\\n+|$))')
  ('def', '\\n+(?=' + block.def.source + ')')
  ();

block.blockquote = replace(block.blockquote)
  ('def', block.def)
  ();

block._tag = '(?!(?:'
  + 'a|em|strong|small|s|cite|q|dfn|abbr|data|time|code'
  + '|var|samp|kbd|sub|sup|i|b|u|mark|ruby|rt|rp|bdi|bdo'
  + '|span|br|wbr|ins|del|img)\\b)\\w+(?!:/|[^\\w\\s@]*@)\\b';

block.html = replace(block.html)
  ('comment', /<!--[\s\S]*?-->/)
  ('closed', /<(tag)[\s\S]+?<\/\1>/)
  ('closing', /<tag(?:"[^"]*"|'[^']*'|[^'">])*?>/)
  (/tag/g, block._tag)
  ();

block.paragraph = replace(block.paragraph)
  ('hr', block.hr)
  ('heading', block.heading)
  ('lheading', block.lheading)
  ('blockquote', block.blockquote)
  ('tag', '<' + block._tag)
  ('def', block.def)
  ();

/**
 * Normal Block Grammar
 */

block.normal = merge({}, block);

/**
 * GFM Block Grammar
 */

block.gfm = merge({}, block.normal, {
  fences: /^ *(`{3,}|~{3,}) *(\S+)? *\n([\s\S]+?)\s*\1 *(?:\n+|$)/,
  paragraph: /^/
});

block.gfm.paragraph = replace(block.paragraph)
  ('(?!', '(?!'
    + block.gfm.fences.source.replace('\\1', '\\2') + '|'
    + block.list.source.replace('\\1', '\\3') + '|')
  ();

/**
 * GFM + Tables Block Grammar
 */

block.tables = merge({}, block.gfm, {
  nptable: /^ *(\S.*\|.*)\n *([-:]+ *\|[-| :]*)\n((?:.*\|.*(?:\n|$))*)\n*/,
  table: /^ *\|(.+)\n *\|( *[-:]+[-| :]*)\n((?: *\|.*(?:\n|$))*)\n*/
});

/**
 * Block Lexer
 */

function Lexer(options) {
  this.tokens = [];
  this.tokens.links = {};
  this.options = options || marked.defaults;
  this.rules = block.normal;

  if (this.options.gfm) {
    if (this.options.tables) {
      this.rules = block.tables;
    } else {
      this.rules = block.gfm;
    }
  }
}

/**
 * Expose Block Rules
 */

Lexer.rules = block;

/**
 * Static Lex Method
 */

Lexer.lex = function(src, options) {
  var lexer = new Lexer(options);
  return lexer.lex(src);
};

/**
 * Preprocessing
 */

Lexer.prototype.lex = function(src) {
  src = src
    .replace(/\r\n|\r/g, '\n')
    .replace(/\t/g, '    ')
    .replace(/\u00a0/g, ' ')
    .replace(/\u2424/g, '\n');

  return this.token(src, true);
};

/**
 * Lexing
 */

Lexer.prototype.token = function(src, top, bq) {
  var src = src.replace(/^ +$/gm, '')
    , next
    , loose
    , cap
    , bull
    , b
    , item
    , space
    , i
    , l;

  while (src) {
    // newline
    if (cap = this.rules.newline.exec(src)) {
      src = src.substring(cap[0].length);
      if (cap[0].length > 1) {
        this.tokens.push({
          type: 'space'
        });
      }
    }

    // code
    if (cap = this.rules.code.exec(src)) {
      src = src.substring(cap[0].length);
      cap = cap[0].replace(/^ {4}/gm, '');
      this.tokens.push({
        type: 'code',
        text: !this.options.pedantic
          ? cap.replace(/\n+$/, '')
          : cap
      });
      continue;
    }

    // fences (gfm)
    if (cap = this.rules.fences.exec(src)) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'code',
        lang: cap[2],
        text: cap[3]
      });
      continue;
    }

    // heading
    if (cap = this.rules.heading.exec(src)) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'heading',
        depth: cap[1].length,
        text: cap[2]
      });
      continue;
    }

    // table no leading pipe (gfm)
    if (top && (cap = this.rules.nptable.exec(src))) {
      src = src.substring(cap[0].length);

      item = {
        type: 'table',
        header: cap[1].replace(/^ *| *\| *$/g, '').split(/ *\| */),
        align: cap[2].replace(/^ *|\| *$/g, '').split(/ *\| */),
        cells: cap[3].replace(/\n$/, '').split('\n')
      };

      for (i = 0; i < item.align.length; i++) {
        if (/^ *-+: *$/.test(item.align[i])) {
          item.align[i] = 'right';
        } else if (/^ *:-+: *$/.test(item.align[i])) {
          item.align[i] = 'center';
        } else if (/^ *:-+ *$/.test(item.align[i])) {
          item.align[i] = 'left';
        } else {
          item.align[i] = null;
        }
      }

      for (i = 0; i < item.cells.length; i++) {
        item.cells[i] = item.cells[i].split(/ *\| */);
      }

      this.tokens.push(item);

      continue;
    }

    // lheading
    if (cap = this.rules.lheading.exec(src)) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'heading',
        depth: cap[2] === '=' ? 1 : 2,
        text: cap[1]
      });
      continue;
    }

    // hr
    if (cap = this.rules.hr.exec(src)) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'hr'
      });
      continue;
    }

    // blockquote
    if (cap = this.rules.blockquote.exec(src)) {
      src = src.substring(cap[0].length);

      this.tokens.push({
        type: 'blockquote_start'
      });

      cap = cap[0].replace(/^ *> ?/gm, '');

      // Pass `top` to keep the current
      // "toplevel" state. This is exactly
      // how markdown.pl works.
      this.token(cap, top, true);

      this.tokens.push({
        type: 'blockquote_end'
      });

      continue;
    }

    // list
    if (cap = this.rules.list.exec(src)) {
      src = src.substring(cap[0].length);
      bull = cap[2];

      this.tokens.push({
        type: 'list_start',
        ordered: bull.length > 1
      });

      // Get each top-level item.
      cap = cap[0].match(this.rules.item);

      next = false;
      l = cap.length;
      i = 0;

      for (; i < l; i++) {
        item = cap[i];

        // Remove the list item's bullet
        // so it is seen as the next token.
        space = item.length;
        item = item.replace(/^ *([*+-]|\d+\.) +/, '');

        // Outdent whatever the
        // list item contains. Hacky.
        if (~item.indexOf('\n ')) {
          space -= item.length;
          item = !this.options.pedantic
            ? item.replace(new RegExp('^ {1,' + space + '}', 'gm'), '')
            : item.replace(/^ {1,4}/gm, '');
        }

        // Determine whether the next list item belongs here.
        // Backpedal if it does not belong in this list.
        if (this.options.smartLists && i !== l - 1) {
          b = block.bullet.exec(cap[i + 1])[0];
          if (bull !== b && !(bull.length > 1 && b.length > 1)) {
            src = cap.slice(i + 1).join('\n') + src;
            i = l - 1;
          }
        }

        // Determine whether item is loose or not.
        // Use: /(^|\n)(?! )[^\n]+\n\n(?!\s*$)/
        // for discount behavior.
        loose = next || /\n\n(?!\s*$)/.test(item);
        if (i !== l - 1) {
          next = item.charAt(item.length - 1) === '\n';
          if (!loose) loose = next;
        }

        this.tokens.push({
          type: loose
            ? 'loose_item_start'
            : 'list_item_start'
        });

        // Recurse.
        this.token(item, false, bq);

        this.tokens.push({
          type: 'list_item_end'
        });
      }

      this.tokens.push({
        type: 'list_end'
      });

      continue;
    }

    // html
    if (cap = this.rules.html.exec(src)) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: this.options.sanitize
          ? 'paragraph'
          : 'html',
        pre: cap[1] === 'pre' || cap[1] === 'script' || cap[1] === 'style',
        text: cap[0]
      });
      continue;
    }

    // def
    if ((!bq && top) && (cap = this.rules.def.exec(src))) {
      src = src.substring(cap[0].length);
      this.tokens.links[cap[1].toLowerCase()] = {
        href: cap[2],
        title: cap[3]
      };
      continue;
    }

    // table (gfm)
    if (top && (cap = this.rules.table.exec(src))) {
      src = src.substring(cap[0].length);

      item = {
        type: 'table',
        header: cap[1].replace(/^ *| *\| *$/g, '').split(/ *\| */),
        align: cap[2].replace(/^ *|\| *$/g, '').split(/ *\| */),
        cells: cap[3].replace(/(?: *\| *)?\n$/, '').split('\n')
      };

      for (i = 0; i < item.align.length; i++) {
        if (/^ *-+: *$/.test(item.align[i])) {
          item.align[i] = 'right';
        } else if (/^ *:-+: *$/.test(item.align[i])) {
          item.align[i] = 'center';
        } else if (/^ *:-+ *$/.test(item.align[i])) {
          item.align[i] = 'left';
        } else {
          item.align[i] = null;
        }
      }

      for (i = 0; i < item.cells.length; i++) {
        item.cells[i] = item.cells[i]
          .replace(/^ *\| *| *\| *$/g, '')
          .split(/ *\| */);
      }

      this.tokens.push(item);

      continue;
    }

    // top-level paragraph
    if (top && (cap = this.rules.paragraph.exec(src))) {
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'paragraph',
        text: cap[1].charAt(cap[1].length - 1) === '\n'
          ? cap[1].slice(0, -1)
          : cap[1]
      });
      continue;
    }

    // text
    if (cap = this.rules.text.exec(src)) {
      // Top-level should never reach here.
      src = src.substring(cap[0].length);
      this.tokens.push({
        type: 'text',
        text: cap[0]
      });
      continue;
    }

    if (src) {
      throw new
        Error('Infinite loop on byte: ' + src.charCodeAt(0));
    }
  }

  return this.tokens;
};

/**
 * Inline-Level Grammar
 */

var inline = {
  escape: /^\\([\\`*{}\[\]()#+\-.!_>])/,
  autolink: /^<([^ >]+(@|:\/)[^ >]+)>/,
  url: noop,
  tag: /^<!--[\s\S]*?-->|^<\/?\w+(?:"[^"]*"|'[^']*'|[^'">])*?>/,
  link: /^!?\[(inside)\]\(href\)/,
  reflink: /^!?\[(inside)\]\s*\[([^\]]*)\]/,
  nolink: /^!?\[((?:\[[^\]]*\]|[^\[\]])*)\]/,
  strong: /^__([\s\S]+?)__(?!_)|^\*\*([\s\S]+?)\*\*(?!\*)/,
  em: /^\b_((?:__|[\s\S])+?)_\b|^\*((?:\*\*|[\s\S])+?)\*(?!\*)/,
  code: /^(`+)\s*([\s\S]*?[^`])\s*\1(?!`)/,
  br: /^ {2,}\n(?!\s*$)/,
  del: noop,
  text: /^[\s\S]+?(?=[\\<!\[_*`]| {2,}\n|$)/
};

inline._inside = /(?:\[[^\]]*\]|[^\[\]]|\](?=[^\[]*\]))*/;
inline._href = /\s*<?([\s\S]*?)>?(?:\s+['"]([\s\S]*?)['"])?\s*/;

inline.link = replace(inline.link)
  ('inside', inline._inside)
  ('href', inline._href)
  ();

inline.reflink = replace(inline.reflink)
  ('inside', inline._inside)
  ();

/**
 * Normal Inline Grammar
 */

inline.normal = merge({}, inline);

/**
 * Pedantic Inline Grammar
 */

inline.pedantic = merge({}, inline.normal, {
  strong: /^__(?=\S)([\s\S]*?\S)__(?!_)|^\*\*(?=\S)([\s\S]*?\S)\*\*(?!\*)/,
  em: /^_(?=\S)([\s\S]*?\S)_(?!_)|^\*(?=\S)([\s\S]*?\S)\*(?!\*)/
});

/**
 * GFM Inline Grammar
 */

inline.gfm = merge({}, inline.normal, {
  escape: replace(inline.escape)('])', '~|])')(),
  url: /^(https?:\/\/[^\s<]+[^<.,:;"')\]\s])/,
  del: /^~~(?=\S)([\s\S]*?\S)~~/,
  text: replace(inline.text)
    (']|', '~]|')
    ('|', '|https?://|')
    ()
});

/**
 * GFM + Line Breaks Inline Grammar
 */

inline.breaks = merge({}, inline.gfm, {
  br: replace(inline.br)('{2,}', '*')(),
  text: replace(inline.gfm.text)('{2,}', '*')()
});

/**
 * Inline Lexer & Compiler
 */

function InlineLexer(links, options) {
  this.options = options || marked.defaults;
  this.links = links;
  this.rules = inline.normal;
  this.renderer = this.options.renderer || new Renderer;
  this.renderer.options = this.options;

  if (!this.links) {
    throw new
      Error('Tokens array requires a `links` property.');
  }

  if (this.options.gfm) {
    if (this.options.breaks) {
      this.rules = inline.breaks;
    } else {
      this.rules = inline.gfm;
    }
  } else if (this.options.pedantic) {
    this.rules = inline.pedantic;
  }
}

/**
 * Expose Inline Rules
 */

InlineLexer.rules = inline;

/**
 * Static Lexing/Compiling Method
 */

InlineLexer.output = function(src, links, options) {
  var inline = new InlineLexer(links, options);
  return inline.output(src);
};

/**
 * Lexing/Compiling
 */

InlineLexer.prototype.output = function(src) {
  var out = ''
    , link
    , text
    , href
    , cap;

  while (src) {
    // escape
    if (cap = this.rules.escape.exec(src)) {
      src = src.substring(cap[0].length);
      out += cap[1];
      continue;
    }

    // autolink
    if (cap = this.rules.autolink.exec(src)) {
      src = src.substring(cap[0].length);
      if (cap[2] === '@') {
        text = cap[1].charAt(6) === ':'
          ? this.mangle(cap[1].substring(7))
          : this.mangle(cap[1]);
        href = this.mangle('mailto:') + text;
      } else {
        text = escape(cap[1]);
        href = text;
      }
      out += this.renderer.link(href, null, text);
      continue;
    }

    // url (gfm)
    if (!this.inLink && (cap = this.rules.url.exec(src))) {
      src = src.substring(cap[0].length);
      text = escape(cap[1]);
      href = text;
      out += this.renderer.link(href, null, text);
      continue;
    }

    // tag
    if (cap = this.rules.tag.exec(src)) {
      if (!this.inLink && /^<a /i.test(cap[0])) {
        this.inLink = true;
      } else if (this.inLink && /^<\/a>/i.test(cap[0])) {
        this.inLink = false;
      }
      src = src.substring(cap[0].length);
      out += this.options.sanitize
        ? escape(cap[0])
        : cap[0];
      continue;
    }

    // link
    if (cap = this.rules.link.exec(src)) {
      src = src.substring(cap[0].length);
      this.inLink = true;
      out += this.outputLink(cap, {
        href: cap[2],
        title: cap[3]
      });
      this.inLink = false;
      continue;
    }

    // reflink, nolink
    if ((cap = this.rules.reflink.exec(src))
        || (cap = this.rules.nolink.exec(src))) {
      src = src.substring(cap[0].length);
      link = (cap[2] || cap[1]).replace(/\s+/g, ' ');
      link = this.links[link.toLowerCase()];
      if (!link || !link.href) {
        out += cap[0].charAt(0);
        src = cap[0].substring(1) + src;
        continue;
      }
      this.inLink = true;
      out += this.outputLink(cap, link);
      this.inLink = false;
      continue;
    }

    // strong
    if (cap = this.rules.strong.exec(src)) {
      src = src.substring(cap[0].length);
      out += this.renderer.strong(this.output(cap[2] || cap[1]));
      continue;
    }

    // em
    if (cap = this.rules.em.exec(src)) {
      src = src.substring(cap[0].length);
      out += this.renderer.em(this.output(cap[2] || cap[1]));
      continue;
    }

    // code
    if (cap = this.rules.code.exec(src)) {
      src = src.substring(cap[0].length);
      out += this.renderer.codespan(escape(cap[2], true));
      continue;
    }

    // br
    if (cap = this.rules.br.exec(src)) {
      src = src.substring(cap[0].length);
      out += this.renderer.br();
      continue;
    }

    // del (gfm)
    if (cap = this.rules.del.exec(src)) {
      src = src.substring(cap[0].length);
      out += this.renderer.del(this.output(cap[1]));
      continue;
    }

    // text
    if (cap = this.rules.text.exec(src)) {
      src = src.substring(cap[0].length);
      out += escape(this.smartypants(cap[0]));
      continue;
    }

    if (src) {
      throw new
        Error('Infinite loop on byte: ' + src.charCodeAt(0));
    }
  }

  return out;
};

/**
 * Compile Link
 */

InlineLexer.prototype.outputLink = function(cap, link) {
  var href = escape(link.href)
    , title = link.title ? escape(link.title) : null;

  return cap[0].charAt(0) !== '!'
    ? this.renderer.link(href, title, this.output(cap[1]))
    : this.renderer.image(href, title, escape(cap[1]));
};

/**
 * Smartypants Transformations
 */

InlineLexer.prototype.smartypants = function(text) {
  if (!this.options.smartypants) return text;
  return text
    // em-dashes
    .replace(/--/g, '\u2014')
    // opening singles
    .replace(/(^|[-\u2014/(\[{"\s])'/g, '$1\u2018')
    // closing singles & apostrophes
    .replace(/'/g, '\u2019')
    // opening doubles
    .replace(/(^|[-\u2014/(\[{\u2018\s])"/g, '$1\u201c')
    // closing doubles
    .replace(/"/g, '\u201d')
    // ellipses
    .replace(/\.{3}/g, '\u2026');
};

/**
 * Mangle Links
 */

InlineLexer.prototype.mangle = function(text) {
  var out = ''
    , l = text.length
    , i = 0
    , ch;

  for (; i < l; i++) {
    ch = text.charCodeAt(i);
    if (Math.random() > 0.5) {
      ch = 'x' + ch.toString(16);
    }
    out += '&#' + ch + ';';
  }

  return out;
};

/**
 * Renderer
 */

function Renderer(options) {
  this.options = options || {};
}

Renderer.prototype.code = function(code, lang, escaped) {
  if (this.options.highlight) {
    var out = this.options.highlight(code, lang);
    if (out != null && out !== code) {
      escaped = true;
      code = out;
    }
  }

  if (!lang) {
    return '<pre><code>'
      + (escaped ? code : escape(code, true))
      + '\n</code></pre>';
  }

  return '<pre><code class="'
    + this.options.langPrefix
    + escape(lang, true)
    + '">'
    + (escaped ? code : escape(code, true))
    + '\n</code></pre>\n';
};

Renderer.prototype.blockquote = function(quote) {
  return '<blockquote>\n' + quote + '</blockquote>\n';
};

Renderer.prototype.html = function(html) {
  return html;
};

Renderer.prototype.heading = function(text, level, raw) {
  return '<h'
    + level
    + ' id="'
    + this.options.headerPrefix
    + raw.toLowerCase().replace(/[^\w]+/g, '-')
    + '">'
    + text
    + '</h'
    + level
    + '>\n';
};

Renderer.prototype.hr = function() {
  return this.options.xhtml ? '<hr/>\n' : '<hr>\n';
};

Renderer.prototype.list = function(body, ordered) {
  var type = ordered ? 'ol' : 'ul';
  return '<' + type + '>\n' + body + '</' + type + '>\n';
};

Renderer.prototype.listitem = function(text) {
  return '<li>' + text + '</li>\n';
};

Renderer.prototype.paragraph = function(text) {
  return '<p>' + text + '</p>\n';
};

Renderer.prototype.table = function(header, body) {
  return '<table>\n'
    + '<thead>\n'
    + header
    + '</thead>\n'
    + '<tbody>\n'
    + body
    + '</tbody>\n'
    + '</table>\n';
};

Renderer.prototype.tablerow = function(content) {
  return '<tr>\n' + content + '</tr>\n';
};

Renderer.prototype.tablecell = function(content, flags) {
  var type = flags.header ? 'th' : 'td';
  var tag = flags.align
    ? '<' + type + ' style="text-align:' + flags.align + '">'
    : '<' + type + '>';
  return tag + content + '</' + type + '>\n';
};

// span level renderer
Renderer.prototype.strong = function(text) {
  return '<strong>' + text + '</strong>';
};

Renderer.prototype.em = function(text) {
  return '<em>' + text + '</em>';
};

Renderer.prototype.codespan = function(text) {
  return '<code>' + text + '</code>';
};

Renderer.prototype.br = function() {
  return this.options.xhtml ? '<br/>' : '<br>';
};

Renderer.prototype.del = function(text) {
  return '<del>' + text + '</del>';
};

Renderer.prototype.link = function(href, title, text) {
  if (this.options.sanitize) {
    try {
      var prot = decodeURIComponent(unescape(href))
        .replace(/[^\w:]/g, '')
        .toLowerCase();
    } catch (e) {
      return '';
    }
    if (prot.indexOf('javascript:') === 0) {
      return '';
    }
  }
  var out = '<a href="' + href + '"';
  if (title) {
    out += ' title="' + title + '"';
  }
  out += '>' + text + '</a>';
  return out;
};

Renderer.prototype.image = function(href, title, text) {
  var out = '<img src="' + href + '" alt="' + text + '"';
  if (title) {
    out += ' title="' + title + '"';
  }
  out += this.options.xhtml ? '/>' : '>';
  return out;
};

/**
 * Parsing & Compiling
 */

function Parser(options) {
  this.tokens = [];
  this.token = null;
  this.options = options || marked.defaults;
  this.options.renderer = this.options.renderer || new Renderer;
  this.renderer = this.options.renderer;
  this.renderer.options = this.options;
}

/**
 * Static Parse Method
 */

Parser.parse = function(src, options, renderer) {
  var parser = new Parser(options, renderer);
  return parser.parse(src);
};

/**
 * Parse Loop
 */

Parser.prototype.parse = function(src) {
  this.inline = new InlineLexer(src.links, this.options, this.renderer);
  this.tokens = src.reverse();

  var out = '';
  while (this.next()) {
    out += this.tok();
  }

  return out;
};

/**
 * Next Token
 */

Parser.prototype.next = function() {
  return this.token = this.tokens.pop();
};

/**
 * Preview Next Token
 */

Parser.prototype.peek = function() {
  return this.tokens[this.tokens.length - 1] || 0;
};

/**
 * Parse Text Tokens
 */

Parser.prototype.parseText = function() {
  var body = this.token.text;

  while (this.peek().type === 'text') {
    body += '\n' + this.next().text;
  }

  return this.inline.output(body);
};

/**
 * Parse Current Token
 */

Parser.prototype.tok = function() {
  switch (this.token.type) {
    case 'space': {
      return '';
    }
    case 'hr': {
      return this.renderer.hr();
    }
    case 'heading': {
      return this.renderer.heading(
        this.inline.output(this.token.text),
        this.token.depth,
        this.token.text);
    }
    case 'code': {
      return this.renderer.code(this.token.text,
        this.token.lang,
        this.token.escaped);
    }
    case 'table': {
      var header = ''
        , body = ''
        , i
        , row
        , cell
        , flags
        , j;

      // header
      cell = '';
      for (i = 0; i < this.token.header.length; i++) {
        flags = { header: true, align: this.token.align[i] };
        cell += this.renderer.tablecell(
          this.inline.output(this.token.header[i]),
          { header: true, align: this.token.align[i] }
        );
      }
      header += this.renderer.tablerow(cell);

      for (i = 0; i < this.token.cells.length; i++) {
        row = this.token.cells[i];

        cell = '';
        for (j = 0; j < row.length; j++) {
          cell += this.renderer.tablecell(
            this.inline.output(row[j]),
            { header: false, align: this.token.align[j] }
          );
        }

        body += this.renderer.tablerow(cell);
      }
      return this.renderer.table(header, body);
    }
    case 'blockquote_start': {
      var body = '';

      while (this.next().type !== 'blockquote_end') {
        body += this.tok();
      }

      return this.renderer.blockquote(body);
    }
    case 'list_start': {
      var body = ''
        , ordered = this.token.ordered;

      while (this.next().type !== 'list_end') {
        body += this.tok();
      }

      return this.renderer.list(body, ordered);
    }
    case 'list_item_start': {
      var body = '';

      while (this.next().type !== 'list_item_end') {
        body += this.token.type === 'text'
          ? this.parseText()
          : this.tok();
      }

      return this.renderer.listitem(body);
    }
    case 'loose_item_start': {
      var body = '';

      while (this.next().type !== 'list_item_end') {
        body += this.tok();
      }

      return this.renderer.listitem(body);
    }
    case 'html': {
      var html = !this.token.pre && !this.options.pedantic
        ? this.inline.output(this.token.text)
        : this.token.text;
      return this.renderer.html(html);
    }
    case 'paragraph': {
      return this.renderer.paragraph(this.inline.output(this.token.text));
    }
    case 'text': {
      return this.renderer.paragraph(this.parseText());
    }
  }
};

/**
 * Helpers
 */

function escape(html, encode) {
  return html
    .replace(!encode ? /&(?!#?\w+;)/g : /&/g, '&amp;')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;')
    .replace(/'/g, '&#39;');
}

function unescape(html) {
  return html.replace(/&([#\w]+);/g, function(_, n) {
    n = n.toLowerCase();
    if (n === 'colon') return ':';
    if (n.charAt(0) === '#') {
      return n.charAt(1) === 'x'
        ? String.fromCharCode(parseInt(n.substring(2), 16))
        : String.fromCharCode(+n.substring(1));
    }
    return '';
  });
}

function replace(regex, opt) {
  regex = regex.source;
  opt = opt || '';
  return function self(name, val) {
    if (!name) return new RegExp(regex, opt);
    val = val.source || val;
    val = val.replace(/(^|[^\[])\^/g, '$1');
    regex = regex.replace(name, val);
    return self;
  };
}

function noop() {}
noop.exec = noop;

function merge(obj) {
  var i = 1
    , target
    , key;

  for (; i < arguments.length; i++) {
    target = arguments[i];
    for (key in target) {
      if (Object.prototype.hasOwnProperty.call(target, key)) {
        obj[key] = target[key];
      }
    }
  }

  return obj;
}


/**
 * Marked
 */

function marked(src, opt, callback) {
  if (callback || typeof opt === 'function') {
    if (!callback) {
      callback = opt;
      opt = null;
    }

    opt = merge({}, marked.defaults, opt || {});

    var highlight = opt.highlight
      , tokens
      , pending
      , i = 0;

    try {
      tokens = Lexer.lex(src, opt)
    } catch (e) {
      return callback(e);
    }

    pending = tokens.length;

    var done = function(err) {
      if (err) {
        opt.highlight = highlight;
        return callback(err);
      }

      var out;

      try {
        out = Parser.parse(tokens, opt);
      } catch (e) {
        err = e;
      }

      opt.highlight = highlight;

      return err
        ? callback(err)
        : callback(null, out);
    };

    if (!highlight || highlight.length < 3) {
      return done();
    }

    delete opt.highlight;

    if (!pending) return done();

    for (; i < tokens.length; i++) {
      (function(token) {
        if (token.type !== 'code') {
          return --pending || done();
        }
        return highlight(token.text, token.lang, function(err, code) {
          if (err) return done(err);
          if (code == null || code === token.text) {
            return --pending || done();
          }
          token.text = code;
          token.escaped = true;
          --pending || done();
        });
      })(tokens[i]);
    }

    return;
  }
  try {
    if (opt) opt = merge({}, marked.defaults, opt);
    return Parser.parse(Lexer.lex(src, opt), opt);
  } catch (e) {
    e.message += '\nPlease report this to https://github.com/chjj/marked.';
    if ((opt || marked.defaults).silent) {
      return '<p>An error occured:</p><pre>'
        + escape(e.message + '', true)
        + '</pre>';
    }
    throw e;
  }
}

/**
 * Options
 */

marked.options =
marked.setOptions = function(opt) {
  merge(marked.defaults, opt);
  return marked;
};

marked.defaults = {
  gfm: true,
  tables: true,
  breaks: true,
  pedantic: false,
  sanitize: false,
  smartLists: false,
  silent: false,
  highlight: null,
  langPrefix: 'lang-',
  smartypants: false,
  headerPrefix: '',
  renderer: new Renderer,
  xhtml: false
};

/**
 * Expose
 */

marked.Parser = Parser;
marked.parser = Parser.parse;

marked.Renderer = Renderer;

marked.Lexer = Lexer;
marked.lexer = Lexer.lex;

marked.InlineLexer = InlineLexer;
marked.inlineLexer = InlineLexer.output;

marked.parse = marked;

if (typeof module !== 'undefined' && typeof exports === 'object') {
  module.exports = marked;
} else if (typeof define === 'function' && define.amd) {
  define(function() { return marked; });
} else {
  this.marked = marked;
}

}).call(function() {
  return this || (typeof window !== 'undefined' ? window : global);
}());


/**
  * Grascale
  */
  
function convertToGrayscale(context, top_x, top_y, width, height){
        //here we are creating a imagedata array same size of the argument array.
	var nimg = context.getImageData( top_x, top_y, width, height );

    var d = nimg.data;

    for (var i=0; i<d.length; i+=4) {
        var r = d[i];
        var g = d[i+1];
        var b = d[i+2];
        // CIE luminance for the RGB
        // The human eye is bad at seeing red and blue, so we de-emphasize them.
        var v = 0.2126*r + 0.7152*g + 0.0722*b;
        d[i] = d[i+1] = d[i+2] = v
      }

    context.putImageData( nimg, top_x, top_y );
}

/**
  * Get flickr photo
  */
  
function getPicture(tags, cb) {
    var apiKey = "fa214b1215cd1a537018cfbdfa7fb9a6"; // replace this with your API key

    var xhr = new XMLHttpRequest(),
        xhr1 = new XMLHttpRequest();
    xhr.onreadystatechange = function() {
        if (xhr.readyState == 4) {
            var data = JSON.parse(xhr.responseText.substring(14,xhr.responseText.length - 1));
            if (data.stat == 'ok') {
                // get a random id from the array
                if(!data.photos.photo.length) {
                    cb("We couldn't find a photo for this. Seperate keywords with commas.");
                }
                else {
                    var photo = data.photos.photo[Math.floor(Math.random() * data.photos.photo.length)];
    
                    // now call the flickr API and get the picture with a nice size
                    xhr1.onreadystatechange = function() {
                        if (xhr1.readyState == 4) {
                            var response = JSON.parse(xhr1.responseText.substring(14,xhr1.responseText.length - 1));
                            if (response.stat == 'ok') {
                                var the_url = response.sizes.size[5].source;
                                cb(null, the_url);
                            } else {
                                 cb("This didn't work out. Try other keywords.");
                            }
                        }
                    }
                    xhr1.open('GET', 'https://api.flickr.com/services/rest/?method=flickr.photos.getSizes&photo_id=' + photo.id + '&api_key=' + apiKey + '&format=json', true);
                    xhr1.send(null);
                }
            } else {
                cb("Flickr seems down?!");
            }
        }
    }
    xhr.open('GET', 'https://api.flickr.com/services/rest/?method=flickr.photos.search&tags=' + encodeURIComponent(tags) + '&api_key=' + apiKey + '&format=json&safe_search=1&content_type=1&sort=relevance&per_page=10', true);
    xhr.send(null);
};