// Thumbnail expansion and reduction animation
//use expandthumb(

exid = 0;
exstep = 0;
exwdth = 0;
exht = 0;
extp = 0;
exlft = 0;
extot = 0;
//extotst = 15;
extotst =15;

function expandthumb(thumbid, fullwidth, fullheight) {
    if (extot != 0) {
        clearTimeout(extot);
    }
    if (exid > 0 && exid != thumbid) {
        restorethumb();
    }
    if (exid != thumbid) {
        img = document.getElementById("screen" + thumbid);
        img.style.display = 'block';
        exid = thumbid;
        exstep = 1;
        exwdth = fullwidth;
        exht = fullheight;
        extp = img.offsetTop;
        exlft = img.offsetLeft;
    } else if (exstep < 1) {
        exstep = 1;
    }
    expandstep();
}

function doexpand() {
    img = document.getElementById("screen" + exid);
    thumb = document.getElementById("thumb" + exid);
    myscroll = getScroll();
    if (extp + thumb.height > myscroll.top + myscroll.height) {
        finaltop = myscroll.top + myscroll.height - exht;
    } else {
        finaltop = extp + thumb.height - exht;
    }
    if (finaltop < myscroll.top) { finaltop = myscroll.top; }
    img.style.top = finaltop + ((extp - finaltop) * (extotst - exstep) / extotst) + 'px';

    if (exlft + thumb.width > myscroll.left + myscroll.width) {
        finalleft = myscroll.left + myscroll.width - exwdth;
    } else {
        finalleft = exlft + thumb.width - exwdth;
    }
    if (finalleft < myscroll.left) { finalleft = myscroll.left; }
   // img.style.left = finalleft + ((exlft - finalleft) * (extotst - exstep) / extotst) + 'px';

    img.width = thumb.width + ((exwdth - thumb.width) * exstep / extotst);
    img.height = thumb.height + ((exht - thumb.height) * exstep / extotst);
}

function restorethumb() {
    img = document.getElementById("screen" + exid);
    img.style.top = '';
    img.style.left = '';
    img.style.display = 'none';
    exid = 0;
}

function expandstep() {
    extot = 0;
    doexpand();
    if (exstep < extotst) {
       // exstep += .5;
        exstep += 1;
       // extot = setTimeout("expandstep()", 20);
        extot = setTimeout("expandstep()", 20);
        
    }
}

function reducestep() {
    extot = 0;
    doexpand();
    if (exstep > 0) {
       // exstep -= .5;
        exstep -= 1;
       // extot = setTimeout("reducestep()", 20);
       extot = setTimeout("reducestep()", 20);

    } else {
        restorethumb();
    }
}

function reducethumb(thumbid) {
    if (extot != 0) {
        clearTimeout(extot);
    }
    if (exstep > 0) {
        reducestep();
    }
}

// returns the scroll position and size of the browser
function getScroll() {
    if (document.all && typeof document.body.scrollTop != "undefined") {
        // IE model
        var ieBox = document.compatMode != "CSS1Compat";
        var cont = ieBox ? document.body : document.documentElement;
        return {
            left: cont.scrollLeft,
            //top: cont.scrollTop,
            width: cont.clientWidth,
            height: cont.clientHeight
        };
    } else {
        return {
           left: window.pageXOffset,
            //top: window.pageYOffset,
            width: window.innerWidth,
            height: window.innerHeight
        };
    }
}