// IXF1.11 :: Image cross-fade 
// *****************************************************
// DOM scripting by brothercake -- http://www.brothercake.com/
/*****************************************************************************
*****************************************************************************/
ixf.imgsLen = ixf.imgs.length;
cacheNextImage(1);
//crossfade setup function
function crossfade() {
    //if the timer is not already going
    if (ixf.clock == null) {
        //copy the image object 
        ixf.obj = arguments[0];
        //copy the image src argument 
        ixf.src = arguments[1][0];
        //store the supported form of opacity
        if (typeof ixf.obj.style.opacity != 'undefined') {
            ixf.type = 'w3c';
        }
        else if (typeof ixf.obj.style.MozOpacity != 'undefined') {
            ixf.type = 'moz';
        }
        else if (typeof ixf.obj.style.KhtmlOpacity != 'undefined') {
            ixf.type = 'khtml';
        }
        else if (typeof ixf.obj.filters == 'object') {
            //weed out win/ie5.0 by testing the length of the filters collection (where filters is an object with no data);
            //then weed out mac/ie5 by testing first the existence of the alpha object (to prevent errors in win/ie5.0);
            //then the returned value type, which should be a number, but in mac/ie5 is an empty string
            ixf.type = (ixf.obj.filters.length > 0 && typeof ixf.obj.filters.alpha == 'object' && typeof ixf.obj.filters.alpha.opacity == 'number') ? 'ie' : 'none';
        }
        else {
            ixf.type = 'none';
        }
        //change the image alt text if defined
        if (typeof arguments[3] != 'undefined' && arguments[3] != '') {
            ixf.obj.alt = arguments[3];
        }
        ixf.obj.alt = arguments[1][1];
        //if any kind of opacity is supported
        if (ixf.type != 'none') {
            //create a new image object and append it to body
            //detecting support for namespaced element creation, in case we're in the XML DOM
            ixf.newimg = document.getElementsByTagName('body')[0].appendChild((typeof document.createElementNS != 'undefined') ? document.createElementNS('http://www.w3.org/1999/xhtml', 'img') : document.createElement('img'));
            //set positioning classname
            ixf.newimg.className = 'idupe';
            //set src to new image src
            ixf.newimg.src = ixf.src
            //move it to superimpose original image
            ixf.newimg.style.left = ixf.getRealPosition(ixf.obj, 'x'); +'px';
            ixf.newimg.style.top = ixf.getRealPosition(ixf.obj, 'y'); +'px';
            //copy and convert fade duration argument 
            ixf.length = parseInt(arguments[2], 10) * 1000;
            //create fade resolution argument as 20 steps per transition
            ixf.resolution = parseInt(arguments[2], 10) * 20;
            //start the timer
            ixf.clock = setInterval('ixf.crossfade()', ixf.length / ixf.resolution);
        }
        //otherwise if opacity is not supported
        else {
            //just do the image swap
            ixf.obj.src = ixf.src;
        }
    }
};

//crossfade timer function
ixf.crossfade = function() {
    //decrease the counter on a linear scale
    ixf.count -= (1 / ixf.resolution); ;
    //if the counter has reached the bottom
    if (ixf.count < (1 / ixf.resolution)) {
        //clear the timer
        clearInterval(ixf.clock);
        ixf.clock = null;
        //reset the counter
        ixf.count = 1;
        //set the original image to the src of the new image
        ixf.obj.src = ixf.src;
    }
    //set new opacity value on both elements
    //using whatever method is supported
    switch (ixf.type) {
        case 'ie':
            ixf.obj.filters.alpha.opacity = ixf.count * 100;
            ixf.newimg.filters.alpha.opacity = (1 - ixf.count) * 100;
            break;
        case 'khtml':
            ixf.obj.style.KhtmlOpacity = ixf.count;
            ixf.newimg.style.KhtmlOpacity = (1 - ixf.count);
            break;
        case 'moz':
            //restrict max opacity to prevent a visual popping effect in firefox
            ixf.obj.style.MozOpacity = (ixf.count == 1 ? 0.9999999 : ixf.count);
            ixf.newimg.style.MozOpacity = (1 - ixf.count);
            break;
        default:
            //restrict max opacity to prevent a visual popping effect in firefox
            ixf.obj.style.opacity = (ixf.count == 1 ? 0.9999999 : ixf.count);
            ixf.newimg.style.opacity = (1 - ixf.count);
    }
    //now that we've gone through one fade iteration 
    //we can show the image that's fading in
    ixf.newimg.style.visibility = 'visible';
    //keep new image in position with original image
    //in case text size changes mid transition or something
    ixf.newimg.style.left = ixf.getRealPosition(ixf.obj, 'x') + 'px';
    ixf.newimg.style.top = ixf.getRealPosition(ixf.obj, 'y') + 'px';
    //if the counter is at the top, which is just after the timer has finished
    if (ixf.count == 1) {
        //remove the duplicate image
        ixf.newimg.parentNode.removeChild(ixf.newimg);
        document.getElementById('toprightcontenttitle').innerHTML = ixf.obj.alt;
    }
};
//get real position method
ixf.getRealPosition = function() {
    this.pos = (arguments[1] == 'x') ? arguments[0].offsetLeft : arguments[0].offsetTop;
    this.tmp = arguments[0].offsetParent;
    while (this.tmp != null) {
        this.pos += (arguments[1] == 'x') ? this.tmp.offsetLeft : this.tmp.offsetTop;
        this.tmp = this.tmp.offsetParent;
    }
    return this.pos;
};

function getImg(x) {
    if (x == 'prev') {
        if (current_img == 0) {
            current_img = ixf.imgsLen - 1;
        } else {
            current_img--;
        }
    } else {
        if (current_img == ixf.imgsLen - 1) {
            current_img = 0;
        } else {
            current_img++;
            cacheNextImage(current_img + 1);
        }
    }
    return ixf.imgs[current_img];
}

//preload next image
function cacheNextImage(nextImgIndex) {
    if (nextImgIndex >= ixf.imgs.length) return;
    if (!ixf.cache) ixf.cache = [];
    if (!ixf.cache[nextImgIndex]) {
        ixf.cache[nextImgIndex] = new Image;
        ixf.cache[nextImgIndex].src = ixf.imgs[nextImgIndex][0];
        ixf.cache[nextImgIndex].alt = ixf.imgs[nextImgIndex][1];
    }
}