// JavaScript Document

/**

* PNG: Adds IE6 support: PNG images for CSS background-image and HTML <IMG/>.

* Author: Drew Diller

* Email: drew.diller@gmail.com

* URL: http://www.dillerdesign.com/experiment/PNG/

* Version: 0.0.7a

* Licensed under the MIT License: http://dillerdesign.com/experiment/PNG/#license

*

* Example usage:

* PNG.fix('.png_bg'); // argument is a CSS selector

* PNG.fixPng( someNode ); // argument is an HTMLDomElement

**/

 

/*

PLEASE READ:

Absolutely everything in this script is SILLY.  I know this.  IE's rendering of certain pixels doesn't make sense, so neither does this code!

*/

 

var PNG = {

 

 ns: 'PNG',

 imgSize: {},

 

 createVmlNameSpace: function() { /* enable VML */

  if (document.namespaces && !document.namespaces[this.ns]) {

    document.namespaces.add(this.ns, 'urn:schemas-microsoft-com:vml');

  }

  if (window.attachEvent) {

   window.attachEvent('onbeforeunload', function() {

    PNG = null;

   });

  }

 },

 

 createVmlStyleSheet: function() { /* style VML, enable behaviors */

  /*

   Just in case lots of other developers have added

   lots of other stylesheets using document.createStyleSheet

   and hit the 31-limit mark, let's not use that method!

   further reading: http://msdn.microsoft.com/en-us/library/ms531194(VS.85).aspx

  */

  var style = document.createElement('style');

  document.documentElement.firstChild.insertBefore(style, document.documentElement.firstChild.firstChild);

  var styleSheet = style.styleSheet;
  
  styleSheet.addRule(this.ns + '\\:*', '{behavior:url(#default#VML)}');

  styleSheet.addRule(this.ns + '\\:shape', 'position:absolute;');

  styleSheet.addRule('img.' + this.ns + '_sizeFinder', 'behavior:none; border:none; position:absolute; z-index:-1; top:-10000px; visibility:hidden;'); /* large negative top value for avoiding vertical scrollbars for large images, suggested by James O'Brien, http://www.thanatopsic.org/hendrik/ */

  this.styleSheet = styleSheet;

 },

 

 readPropertyChange: function() {

  var el = event.srcElement;

  if (event.propertyName.search('background') != -1 || event.propertyName.search('border') != -1) {

   PNG.applyVML(el);

  }

  if (event.propertyName == 'style.display') {

   var display = (el.currentStyle.display == 'none') ? 'none' : 'block';

   for (var v in el.vml) {

    el.vml[v].shape.style.display = display;

   }

  }

  if (event.propertyName.search('filter') != -1) {

   PNG.vmlOpacity(el);

  }

 },

 

 vmlOpacity: function(el) {

  if (el.currentStyle.filter.search('lpha') != -1) {

   var trans = el.currentStyle.filter;

   trans = parseInt(trans.substring(trans.lastIndexOf('=')+1, trans.lastIndexOf(')')), 10)/100;

   el.vml.color.shape.style.filter = el.currentStyle.filter; /* complete guesswork */

   el.vml.image.fill.opacity = trans; /* complete guesswork */

  }

 },

 

 handlePseudoHover: function(el) {

  setTimeout(function() { /* wouldn't work as intended without setTimeout */

   PNG.applyVML(el);

  }, 1);

 },

 

 /**

 * This is the method to use in a document.

 * @param {String} selector - REQUIRED - a CSS selector, such as '#doc .container'

 **/

 fix: function(selector) {

  var selectors = selector.split(','); /* multiple selectors supported, no need for multiple calls to this anymore */

  for (var i=0; i<selectors.length; i++) {

   this.styleSheet.addRule(selectors[i], 'behavior:expression(PNG.fixPng(this))'); /* seems to execute the function without adding it to the stylesheet - interesting... */

  }

 },

 

 applyVML: function(el) {

  el.runtimeStyle.cssText = '';

  this.vmlFill(el);

  this.vmlOffsets(el);

  this.vmlOpacity(el);

  if (el.isImg) {

   this.copyImageBorders(el);

  }

 },

 

 attachHandlers: function(el) {

  var self = this;

  var handlers = {resize: 'vmlOffsets', move: 'vmlOffsets'};

  if (el.nodeName == 'A') {

   var moreForAs = {mouseleave: 'handlePseudoHover', mouseenter: 'handlePseudoHover', focus: 'handlePseudoHover', blur: 'handlePseudoHover'};

   for (var a in moreForAs) {

    handlers[a] = moreForAs[a];

   }

  }

  for (var h in handlers) {

   el.attachEvent('on' + h, function() {

    self[handlers[h]](el);

   });

  }

  el.attachEvent('onpropertychange', this.readPropertyChange);

 },

 

 giveLayout: function(el) {

  el.style.zoom = 1;

  if (el.currentStyle.position == 'static') {

   el.style.position = 'relative';

  }

 },

 

 copyImageBorders: function(el) {

  var styles = {'borderStyle':true, 'borderWidth':true, 'borderColor':true};

  for (var s in styles) {

   el.vml.color.shape.style[s] = el.currentStyle[s];

  }

 },

 

 vmlFill: function(el) {

  if (!el.currentStyle) {

   return;

  } else {

   var elStyle = el.currentStyle;

  }

  for (var v in el.vml) {

   el.vml[v].shape.style.zIndex = elStyle.zIndex;

  }

  el.runtimeStyle.backgroundColor = '';

  el.runtimeStyle.backgroundImage = '';

  var noColor = (elStyle.backgroundColor == 'transparent');

  var noImg = true;

  if (elStyle.backgroundImage != 'none' || el.isImg) {

   if (!el.isImg) {

    el.vmlBg = elStyle.backgroundImage;

    el.vmlBg = el.vmlBg.substr(5, el.vmlBg.lastIndexOf('")')-5);

   }

   else {

    el.vmlBg = el.src;

   }

   var lib = this;

   if (!lib.imgSize[el.vmlBg]) { /* determine size of loaded image */

    var img = document.createElement('img');

    lib.imgSize[el.vmlBg] = img;

    img.className = lib.ns + '_sizeFinder';

    img.runtimeStyle.cssText = 'behavior:none; position:absolute; left:-10000px; top:-10000px; border:none;'; /* make sure to set behavior to none to prevent accidental matching of the helper elements! */

    img.attachEvent('onload', function() {

     this.width = this.offsetWidth; /* weird cache-busting requirement! */

     this.height = this.offsetHeight;

     lib.vmlOffsets(el);

    });
 
    img.src = el.vmlBg;

    img.removeAttribute('width');

    img.removeAttribute('height');

    document.body.insertBefore(img, document.body.firstChild);

   }

   el.vml.image.fill.src = el.vmlBg;

   noImg = false;

  }

  el.vml.image.fill.on = !noImg;

  el.vml.image.fill.color = 'none';

  el.vml.color.shape.style.backgroundColor = elStyle.backgroundColor;

  el.runtimeStyle.backgroundImage = 'none';

  el.runtimeStyle.backgroundColor = 'transparent';

 },

 

 /* IE can't figure out what do when the offsetLeft and the clientLeft add up to 1, and the VML ends up getting fuzzy... so we have to push/enlarge things by 1 pixel and then clip off the excess */

 vmlOffsets: function(el) {

  var thisStyle = el.currentStyle;

  var size = {'W':el.clientWidth+1, 'H':el.clientHeight+1, 'w':this.imgSize[el.vmlBg].width, 'h':this.imgSize[el.vmlBg].height, 'L':el.offsetLeft, 'T':el.offsetTop, 'bLW':el.clientLeft, 'bTW':el.clientTop};

  var fudge = (size.L + size.bLW == 1) ? 1 : 0;

  

  /* vml shape, left, top, width, height, origin */

  var makeVisible = function(vml, l, t, w, h, o) {

   vml.coordsize = w+','+h;

   vml.coordorigin = o+','+o;

   vml.path = 'm0,0l'+w+',0l'+w+','+h+'l0,'+h+' xe';

   vml.style.width = w + 'px';

   vml.style.height = h + 'px';

   vml.style.left = l + 'px';

   vml.style.top = t + 'px';

  };

  makeVisible(el.vml.color.shape, (size.L + (el.isImg ? 0 : size.bLW)), (size.T + (el.isImg ? 0 : size.bTW)), (size.W-1), (size.H-1), 0);

  makeVisible(el.vml.image.shape, (size.L + size.bLW), (size.T + size.bTW), (size.W), (size.H), 1);

  

  var bg = {'X':0, 'Y':0};

  var figurePercentage = function(axis, position) {

   var fraction = true;

   switch(position) {

    case 'left':

    case 'top':

     bg[axis] = 0;

     break;

    case 'center':

     bg[axis] = .5;

     break;

    case 'right':

    case 'bottom':

     bg[axis] = 1;

     break;

    default:

     if (position.search('%') != -1) {

      bg[axis] = parseInt(position)*.01;

     }

     else {

      fraction = false;

     }

   }

   var horz = (axis == 'X');

   bg[axis] = Math.ceil(fraction ? ( (size[horz?'W': 'H'] * bg[axis]) - (size[horz?'w': 'h'] * bg[axis]) ) : parseInt(position));

   if (bg[axis] == 0) {

    bg[axis]++;

   }

  };

  for (var b in bg) {

   figurePercentage(b, thisStyle['backgroundPosition'+b]);

  }

  

  el.vml.image.fill.position = (bg.X/size.W) + ',' + (bg.Y/size.H);

  

  var bgR = thisStyle.backgroundRepeat;

  var dC = {'T':1, 'R':size.W+fudge, 'B':size.H, 'L':1+fudge}; /* these are defaults for repeat of any kind */

  var altC = { 'X': {'b1': 'L', 'b2': 'R', 'd': 'W'}, 'Y': {'b1': 'T', 'b2': 'B', 'd': 'H'} };

  if (bgR != 'repeat') {

   var c = {'T':(bg.Y), 'R':(bg.X+size.w), 'B':(bg.Y+size.h), 'L':(bg.X)}; /* these are defaults for no-repeat - clips down to the image location */

   if (bgR.search('repeat-') != -1) { /* now let's revert to dC for repeat-x or repeat-y */

    var v = bgR.split('repeat-')[1].toUpperCase();

    c[altC[v].b1] = 1;

    c[altC[v].b2] = size[altC[v].d];

   }

   if (c.B > size.H) {

    c.B = size.H;

   }

   el.vml.image.shape.style.clip = 'rect('+c.T+'px '+(c.R+fudge)+'px '+c.B+'px '+(c.L+fudge)+'px)';

  }

  else {

   el.vml.image.shape.style.clip = 'rect('+dC.T+'px '+dC.R+'px '+dC.B+'px '+dC.L+'px)';

  }

 },

 

 fixPng: function(el) {

  el.style.behavior = 'none';

  if (el.nodeName == 'BODY' || el.nodeName == 'TD' || el.nodeName == 'TR') { /* elements not supported yet */

   return;

  }

  el.isImg = false;

  if (el.nodeName == 'IMG') {

   if(el.src.toLowerCase().search(/\.png$/) != -1) {

    el.isImg = true;

    el.style.visibility = 'hidden';

   }

   else {

    return;

   }

  }

  else if (el.currentStyle.backgroundImage.toLowerCase().search('.png') == -1) {

   return;

  }

  var lib = PNG;

  el.vml = {color: {}, image: {}};

  var els = {shape: {}, fill: {}};

  for (var r in el.vml) {

   for (var e in els) {

    var nodeStr = lib.ns + ':' + e;

    el.vml[r][e] = document.createElement(nodeStr);

   }

   el.vml[r].shape.stroked = false;

   el.vml[r].shape.appendChild(el.vml[r].fill);

   el.parentNode.insertBefore(el.vml[r].shape, el);

  }

  el.vml.image.shape.fillcolor = 'none'; /* Don't show blank white shapeangle when waiting for image to load. */

  el.vml.image.fill.type = 'tile'; /* Ze magic!! Makes image show up. */

  el.vml.color.fill.on = false; /* Actually going to apply vml element's style.backgroundColor, so hide the whiteness. */

  

  lib.attachHandlers(el);

  

  lib.giveLayout(el);

  lib.giveLayout(el.offsetParent);

  

  /* set up element */

  lib.applyVML(el);

 }

 

};

try {

 document.execCommand("BackgroundImageCache", false, true); /* TredoSoft Multiple IE doesn't like this, so try{} it */

} catch(r) {}

PNG.createVmlNameSpace();

PNG.createVmlStyleSheet();