/**
* DD_belatedPNG: 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/DD_belatedPNG/
* Version: 0.0.8a
* Licensed under the MIT License: http://dillerdesign.com/experiment/DD_belatedPNG/#license
*
* Example usage:
* DD_belatedPNG.fix('.png_bg'); // argument is a CSS selector
* DD_belatedPNG.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 DD_belatedPNG = {
    ns: 'DD_belatedPNG',
    imgSize: {},
    delay: 10,
    nodesFixed: 0,
    createVmlNameSpace: function () { /* enable VML */
        if (document.namespaces && !document.namespaces[this.ns]) {
            document.namespaces.add(this.ns, 'urn:schemas-microsoft-com:vml');
        }
    },
    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 screenStyleSheet, printStyleSheet;
        screenStyleSheet = document.createElement('style');
        screenStyleSheet.setAttribute('media', 'screen');
        document.documentElement.firstChild.insertBefore(screenStyleSheet, document.documentElement.firstChild.firstChild);
        if (screenStyleSheet.styleSheet) {
            screenStyleSheet = screenStyleSheet.styleSheet;
            screenStyleSheet.addRule(this.ns + '\\:*', '{behavior:url(#default#VML)}');
            screenStyleSheet.addRule(this.ns + '\\:shape', 'position:absolute;');
            screenStyleSheet.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.screenStyleSheet = screenStyleSheet;

            /* Add a print-media stylesheet, for preventing VML artifacts from showing up in print (including preview). */
            /* Thanks to Rémi Prévost for automating this! */
            printStyleSheet = document.createElement('style');
            printStyleSheet.setAttribute('media', 'print');
            document.documentElement.firstChild.insertBefore(printStyleSheet, document.documentElement.firstChild.firstChild);
            printStyleSheet = printStyleSheet.styleSheet;
            printStyleSheet.addRule(this.ns + '\\:*', '{display: none !important;}');
            printStyleSheet.addRule('img.' + this.ns + '_sizeFinder', '{display: none !important;}');
        }
    },
    readPropertyChange: function () {
        var el, display, v;
        el = event.srcElement;
        if (!el.vmlInitiated) {
            return;
        }
        if (event.propertyName.search('background') != -1 || event.propertyName.search('border') != -1) {
            DD_belatedPNG.applyVML(el);
        }
        if (event.propertyName == 'style.display') {
            display = (el.currentStyle.display == 'none') ? 'none' : 'block';
            for (v in el.vml) {
                if (el.vml.hasOwnProperty(v)) {
                    el.vml[v].shape.style.display = display;
                }
            }
        }
        if (event.propertyName.search('filter') != -1) {
            DD_belatedPNG.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 */
            DD_belatedPNG.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) {
        if (this.screenStyleSheet) {
            var selectors, i;
            selectors = selector.split(','); /* multiple selectors supported, no need for multiple calls to this anymore */
            for (i=0; i<selectors.length; i++) {
                this.screenStyleSheet.addRule(selectors[i], 'behavior:expression(DD_belatedPNG.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, handlers, handler, moreForAs, a, h;
        self = this;
        handlers = {
            resize: 'vmlOffsets',
            move: 'vmlOffsets'
        };
        if (el.nodeName == 'A') {
            moreForAs = {
                mouseleave: 'handlePseudoHover',
                mouseenter: 'handlePseudoHover',
                focus: 'handlePseudoHover',
                blur: 'handlePseudoHover'
            };
            for (a in moreForAs) {
                if (moreForAs.hasOwnProperty(a)) {
                    handlers[a] = moreForAs[a];
                }
            }
        }
        for (h in handlers) {
            if (handlers.hasOwnProperty(h)) {
                handler = function () {
                    self[handlers[h]](el);
                };
                el.attachEvent('on' + h, handler);
            }
        }
        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, s;
        styles = {
            'borderStyle':true,
            'borderWidth':true,
            'borderColor':true
        };
        for (s in styles) {
            if (styles.hasOwnProperty(s)) {
                el.vml.color.shape.style[s] = el.currentStyle[s];
            }
        }
    },
    vmlFill: function (el) {
        if (!el.currentStyle) {
            return;
        } else {
            var elStyle, noImg, lib, v, img, imgLoaded;
            elStyle = el.currentStyle;
        }
        for (v in el.vml) {
            if (el.vml.hasOwnProperty(v)) {
                el.vml[v].shape.style.zIndex = elStyle.zIndex;
            }
        }
        el.runtimeStyle.backgroundColor = '';
        el.runtimeStyle.backgroundImage = '';
        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;
            }
            lib = this;
            if (!lib.imgSize[el.vmlBg]) { /* determine size of loaded image */
                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; margin:0; padding:0;'; /* make sure to set behavior to none to prevent accidental matching of the helper elements! */
                imgLoaded = function () {
                    this.width = this.offsetWidth; /* weird cache-busting requirement! */
                    this.height = this.offsetHeight;
                    lib.vmlOffsets(el);
                };
                img.attachEvent('onload', imgLoaded);
                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, size, fudge, makeVisible, bg, bgR, dC, altC, b, c, v;
        thisStyle = el.currentStyle;
        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
            };
        fudge = (size.L + size.bLW == 1) ? 1 : 0;
        /* vml shape, left, top, width, height, origin */
        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 );
        bg = {
            'X':0,
            'Y':0
        };
        if (el.isImg) {
            bg.X = parseInt(thisStyle.paddingLeft, 10) + 1;
            bg.Y = parseInt(thisStyle.paddingTop, 10) + 1;
        }
        else {
            for (b in bg) {
                if (bg.hasOwnProperty(b)) {
                    this.figurePercentage(bg, size, b, thisStyle['backgroundPosition'+b]);
                }
            }
        }
        el.vml.image.fill.position = (bg.X/size.W) + ',' + (bg.Y/size.H);
        bgR = thisStyle.backgroundRepeat;
        dC = {
            'T':1,
            'R':size.W+fudge,
            'B':size.H,
            'L':1+fudge
            }; /* these are defaults for repeat of any kind */
        altC = {
            'X': {
                'b1': 'L',
                'b2': 'R',
                'd': 'W'
            },
            'Y': {
                'b1': 'T',
                'b2': 'B',
                'd': 'H'
            }
        };
    if (bgR != 'repeat' || el.isImg) {
        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 */
            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)';
    }
},
figurePercentage: function (bg, size, axis, position) {
    var horizontal, fraction;
    fraction = true;
    horizontal = (axis == 'X');
    switch(position) {
        case 'left':
        case 'top':
            bg[axis] = 0;
            break;
        case 'center':
            bg[axis] = 0.5;
            break;
        case 'right':
        case 'bottom':
            bg[axis] = 1;
            break;
        default:
            if (position.search('%') != -1) {
                bg[axis] = parseInt(position, 10) / 100;
            }
            else {
                fraction = false;
            }
    }
    bg[axis] = Math.ceil(  fraction ? ( (size[horizontal?'W': 'H'] * bg[axis]) - (size[horizontal?'w': 'h'] * bg[axis]) ) : parseInt(position, 10)  );
    if (bg[axis] % 2 === 0) {
        bg[axis]++;
    }
    return bg[axis];
},
fixPng: function (el) {
    el.style.behavior = 'none';
    var lib, els, nodeStr, v, e;
    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;
    }
    lib = DD_belatedPNG;
    el.vml = {
        color: {},
        image: {}
};
els = {
    shape: {},
    fill: {}
};
for (v in el.vml) {
    if (el.vml.hasOwnProperty(v)) {
        for (e in els) {
            if (els.hasOwnProperty(e)) {
                nodeStr = lib.ns + ':' + e;
                el.vml[v][e] = document.createElement(nodeStr);
            }
        }
        el.vml[v].shape.stroked = false;
        el.vml[v].shape.appendChild(el.vml[v].fill);
        el.parentNode.insertBefore(el.vml[v].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'; /* 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);
el.vmlInitiated = true;
lib.applyVML(el); /* Render! */
}
};
try {
    document.execCommand("BackgroundImageCache", false, true); /* TredoSoft Multiple IE doesn't like this, so try{} it */
} catch(r) {}
DD_belatedPNG.createVmlNameSpace();
DD_belatedPNG.createVmlStyleSheet();