// IXF1.0 :: Image cross-fade
// *****************************************************
// DOM scripting by brothercake -- http://www.brothercake.com/
//******************************************************
//global object
var ixw = { 'clock' : null, 'count' : 1 }
/*******************************************************


/*****************************************************************************
 List the images that need to be cached
*****************************************************************************/
/* --- NBC $$ 08-11-2008 $$
ixw.imgs = [
    'buttons/udm4-greenbutton88x31.gif',
    'buttons/udm4-whitebutton88x31.gif',
    'buttons/udm4-bluebutton88x31.gif',
    'buttons/udm4-redbutton88x31.gif',
    'buttons/udm4-purplebutton88x31.gif',
    'buttons/udm4-blackbutton88x31.gif',
    ];
*/
/*****************************************************************************
*****************************************************************************/



//cache the images
/* ---- NBC $$ 08-11-2008 $$
ixw.imgsLen = ixw.imgs.length;
ixw.cache = [];
for(var i=0; i<ixw.imgsLen; i++)
{
    ixw.cache[i] = new Image;
    ixw.cache[i].src = ixw.imgs[i];
}

*/
//crosswipe setup function
function crosswipe()
{
    //if the timer is not already going
    if(ixw.clock == null)
    {
        //copy the image object
        ixw.obj = arguments[0];

        //get its dimensions
        ixw.size = { 'w' : ixw.obj.width, 'h' : ixw.obj.height };

        //copy the image src argument
        ixw.src = arguments[1];

        //change the image alt text if defined
        if(typeof arguments[4] != 'undefined' && arguments[4] != '')
        {
            ixw.obj.alt = arguments[4];
        }

        //if dynamic element creation is supported
        if(typeof document.createElementNS != 'undefined' || typeof document.createElement != 'undefined')
        {
            //create a new image object and append it to body
            //detecting support for namespaced element creation, in case we're in the XML DOM
            ixw.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
            ixw.newimg.className = 'idupe';

            //set src to new image src
            ixw.newimg.src = ixw.src

            //move it to superimpose original image
            ixw.newimg.style.left = ixw.getRealPosition(ixw.obj, 'x') + 'px';
            ixw.newimg.style.top = ixw.getRealPosition(ixw.obj, 'y') + 'px';

            //set it to be completely hidden with clip
            ixw.newimg.style.clip = 'rect(0, 0, 0, 0)';

            //show the image
            ixw.newimg.style.visibility = 'visible';

            //copy and convert fade duration argument
            ixw.length = parseInt(arguments[2], 10) * 1000;

            //create fade resolution argument as 20 steps per transition
            ixw.resolution = parseInt(arguments[2], 10) * 20;

            //copy slide direction argument
            ixw.dir = arguments[3];

            //start the timer
            ixw.clock = setInterval('ixw.crosswipe()', ixw.length/ixw.resolution);
        }

        //otherwise if dynamic element creation is not supported
        else
        {
            //just do the image swap
            ixw.obj.src = ixw.src;
        }

    }
};


//crosswipe timer function
ixw.crosswipe = function()
{
    //decrease the counter on a linear scale
    ixw.count -= (1 / ixw.resolution);

    //if the counter has reached the bottom
    if(ixw.count < (1 / ixw.resolution))
    {
        //clear the timer
        clearInterval(ixw.clock);
        ixw.clock = null;

        //reset the counter
        ixw.count = 1;

        //set the original image to the src of the new image
        ixw.obj.src = ixw.src;
    }

    //animate the clip of the new image
    //using the width and height properties we saved earlier
    ixw.newimg.style.clip = 'rect('
        + ( (/bt|bltr|brtl/.test(ixw.dir)) ? (ixw.size.h * ixw.count) : (/che|cc/.test(ixw.dir)) ? ((ixw.size.h * ixw.count) / 2) : (0) )
        + 'px, '
        + ( (/lr|tlbr|bltr/.test(ixw.dir)) ? (ixw.size.w - (ixw.size.w * ixw.count)) : (/cve|cc/.test(ixw.dir)) ? (ixw.size.w - ((ixw.size.w * ixw.count) / 2)) : (ixw.size.w) )
        + 'px, '
        + ( (/tb|tlbr|trbl/.test(ixw.dir)) ? (ixw.size.h - (ixw.size.h * ixw.count)) : (/che|cc/.test(ixw.dir)) ? (ixw.size.h - ((ixw.size.h * ixw.count) / 2)) : (ixw.size.h) )
        + 'px, '
        + ( (/lr|tlbr|bltr/.test(ixw.dir)) ? (0) : (/tb|bt|che/.test(ixw.dir)) ? (0) : (/cve|cc/.test(ixw.dir)) ? ((ixw.size.w * ixw.count) / 2) : (ixw.size.w * ixw.count) )
        + 'px)';

    //keep new image in position with original image
    //in case text size changes mid transition or something
    ixw.newimg.style.left = ixw.getRealPosition(ixw.obj, 'x') + 'px';
    ixw.newimg.style.top = ixw.getRealPosition(ixw.obj, 'y') + 'px';

    //if the counter is at the top, which is just after the timer has finished
    if(ixw.count == 1)
    {
        //remove the duplicate image
        ixw.newimg.parentNode.removeChild(ixw.newimg);
    }
};



//get real position method
ixw.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;
};