function openNewImage(src, imgWidth, imgHeight) {
    var dividr = document.getElementById("gallerydiv");
    var divido = document.getElementById("gallerydivoveral");
    var imageid = document.getElementById("galleryimg");
    var loading = document.getElementById("gallery_preloader");
    var imgLoading = document.getElementById("gallery_preloader_img");

    loading.style.display = 'block';
    imageid.style.visibility = 'hidden';
    dividr.style.visibility = 'hidden';
    divido.style.display = 'block';
    dividr.style.display = 'block';

    var str = '<img id="galleryimg" onclick="closeImg()" class="galleryimg" onload="finishedDownload()" ';


    var imageid = document.getElementById("galleryimg");

    // pro next a previous pocitani velikosti
    if (!imgWidth) {
        var m_img = new Image();
        m_img.src = src;

        imgWidth = m_img.width;
        imgHeight = m_img.height;

        var t = setTimeout("openNewImage( '" + src + "', " + imgWidth + ", " +
        imgHeight + ")", 250);

        return false;
    }

    winW = pageWidth();
    winH = pageHeight();

    limitwinW = winW*0.8;
    limitwinH = winH*0.8;

    if (imgWidth>limitwinW || imgHeight > limitwinH) {
        rw = imgWidth/limitwinW;
        rh = imgHeight/limitwinH;
        if (rw>rh) {
            imgWidth = limitwinW;
            imgHeight /= rw;
        } else {
            imgHeight = limitwinH;
            imgWidth /= rh;
        }
    }

    browser = navigator.appName;

    divido.style.visibility = 'visible';
    divido.style.width  = winW + 'px';
    divido.style.height = winH + 'px';
    dividr.style.left = winW/2-imgWidth/2;

    if (browser != "Microsoft Internet Explorer") {
        dividr.style.top = winH/2-imgHeight/2 + 'px';

        loading.style.top = winH/2-imgLoading.height/2 + 'px';
    }

    str += 'width="' + imgWidth + '" ';
    str += 'height"' + imgHeight + '" ';

    str += 'src="' + src + '" ';
    str += 'alt="' + src + '">';

    document.getElementById("galleryimgput").innerHTML = str;

    return false;
}


function finishedDownload() {
    var imageid = document.getElementById("galleryimg");
    var dividr = document.getElementById("gallerydiv");
    var loading = document.getElementById("gallery_preloader");

    loading.style.display = 'none';
    imageid.style.visibility = 'visible';
    dividr.style.visibility = 'visible';
}


function nextImg() {
    var imageid = document.getElementById("galleryimg");
    var actimg = imageid.alt;
    var test = false;

    for (img in pictures) {
        if (test) break;
        if (pictures[img] == actimg) {
            test = true;
        }
    }

    if (test) {
        openNewImage(pictures[img], 0, 0);
    }
}


function prevImg() {
    var imageid = document.getElementById("galleryimg");
    var actimg = imageid.alt;
    var old;
    var test = false;

    for (img in pictures) {
        if (pictures[img] == actimg) {
            test = true;
            break;
        }
        old = pictures[img];
    }

    if (test && (old) ) {
        openNewImage(old,0,0);
    }
}


function calculateTopWidthImage(id) {
    var imageid = document.getElementById(id);

    topScreen = document.documentElement.scrollTop ?
    document.documentElement.scrollTop : document.body.scrollTop;

    constant = (pageHeight()/2 - imageid.height/2);

    result = topScreen + constant;

    return result;
}


function putImage(src, imgWidth, imgHeight, maxw, maxh) {
    var dividr = document.getElementById("divgalleryimg");
    var divout = document.getElementById("usedivout");

    if (imgWidth > maxw || imgHeight > maxh) {
        rw = imgWidth/maxw;
        rh = imgHeight/maxh;
        if (rw>rh) {
            imgWidth = maxw;
            imgHeight /= rw;
        } else {
            imgHeight = maxh;
            imgWidth /= rh;
        }
    }

    dividr.width = Math.round(imgWidth);
    dividr.height = Math.round(imgHeight);
    dividr.src = src;

    return false;
}


function closeImg() {
    var dividr = document.getElementById("gallerydiv");
    var divido = document.getElementById("gallerydivoveral");
    var imageid = document.getElementById("galleryimg");

    imageid.style.visibility = 'hidden';
    divido.style.display = 'none';
    dividr.style.display = 'none';
}


// Browser Window Size and Position
// copyright Stephen Chapman, 3rd Jan 2005, 8th Dec 2005
function pageWidth() {
    return window.innerWidth != null ? window.innerWidth : document.documentElement &&
    document.documentElement.clientWidth ? document.documentElement.clientWidth : document.body != null ?
    document.body.clientWidth : null;
}


function pageHeight() {
    return  window.innerHeight != null? window.innerHeight : document.documentElement &&
    document.documentElement.clientHeight ? document.documentElement.clientHeight : document.body != null ?
    document.body.clientHeight : null;} function posLeft() {return typeof window.pageXOffset != 'undefined' ?
    window.pageXOffset :document.documentElement && document.documentElement.scrollLeft ?
    document.documentElement.scrollLeft : document.body.scrollLeft ? document.body.scrollLeft : 0;
}


function posTop() {
    return typeof window.pageYOffset != 'undefined' ?
    window.pageYOffset : document.documentElement &&
    document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop ?
    document.body.scrollTop : 0;
}


function posRight() {
    return posLeft()+pageWidth();
}


function posBottom() {
    return posTop()+pageHeight();
}