source: branches/dev/html/products/lightbox.js @ 8

/*
    Lightbox JS: Fullsize Image Overlays 
    by Lokesh Dhakar - http://www.huddletogether.com

    For more information on this script, visit:
    http://huddletogether.com/projects/lightbox/

    Licensed under the Creative Commons Attribution 2.5 License - http://creativecommons.org/licenses/by/2.5/
    (basically, do anything you want, just leave my name and link)
    
    Table of Contents
    -----------------
    Configuration
    
    Functions
    - getPageScroll()
    - getPageSize()
    - pause()
    - getKey()
    - listenKey()
    - showLightbox()
    - hideLightbox()
    - initLightbox()
    - addLoadEvent()
    
    Function Calls
    - addLoadEvent(initLightbox)

*/



//
// Configuration
//

// If you would like to use a custom loading image or close button reference them in the next two lines.
var loadingImage = 'loading.gif';       
var closeButton = 'close.gif';      





//
// getPageScroll()
// Returns array with x,y page scroll values.
// Core code from - quirksmode.org
//
function getPageScroll(){

    var yScroll;

    if (self.pageYOffset) {
        yScroll = self.pageYOffset;
    } else if (document.documentElement && document.documentElement.scrollTop){  // Explorer 6 Strict
        yScroll = document.documentElement.scrollTop;
    } else if (document.body) {// all other Explorers
        yScroll = document.body.scrollTop;
    }

    arrayPageScroll = new Array('',yScroll) 
    return arrayPageScroll;
}



//
// getPageSize()
// Returns array with page width, height and window width, height
// Core code from - quirksmode.org
// Edit for Firefox by pHaez
//
function getPageSize(){
    
    var xScroll, yScroll;
    
    if (window.innerHeight && window.scrollMaxY) {  
        xScroll = document.body.scrollWidth;
        yScroll = window.innerHeight + window.scrollMaxY;
    } else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
        xScroll = document.body.scrollWidth;
        yScroll = document.body.scrollHeight;
    } else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
        xScroll = document.body.offsetWidth;
        yScroll = document.body.offsetHeight;
    }
    
    var windowWidth, windowHeight;
    if (self.innerHeight) { // all except Explorer
        windowWidth = self.innerWidth;
        windowHeight = self.innerHeight;
    } else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
        windowWidth = document.documentElement.clientWidth;
        windowHeight = document.documentElement.clientHeight;
    } else if (document.body) { // other Explorers
        windowWidth = document.body.clientWidth;
        windowHeight = document.body.clientHeight;
    }   
    
    // for small pages with total height less then height of the viewport
    if(yScroll < windowHeight){
        pageHeight = windowHeight;
    } else { 
        pageHeight = yScroll;
    }

    // for small pages with total width less then width of the viewport
    if(xScroll < windowWidth){  
        pageWidth = windowWidth;
    } else {
        pageWidth = xScroll;
    }


    arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight) 
    return arrayPageSize;
}


//
// pause(numberMillis)
// Pauses code execution for specified time. Uses busy code, not good.
// Code from http://www.faqts.com/knowledge_base/view.phtml/aid/1602
//
function pause(numberMillis) {
    var now = new Date();
    var exitTime = now.getTime() + numberMillis;
    while (true) {
        now = new Date();
        if (now.getTime() > exitTime)
            return;
    }
}

//
// getKey(key)
// Gets keycode. If 'x' is pressed then it hides the lightbox.
//

function getKey(e){
    if (e == null) { // ie
        keycode = event.keyCode;
    } else { // mozilla
        keycode = e.which;
    }
    key = String.fromCharCode(keycode).toLowerCase();
    
    if(key == 'x'){ hideLightbox(); }
}


//
// listenKey()
//
function listenKey () { document.onkeypress = getKey; }
    

//
// showLightbox()
// Preloads images. Pleaces new image in lightbox then centers and displays.
//
function showLightbox(objLink)
{
    // prep objects
    var objOverlay = document.getElementById('overlay');
    var objLightbox = document.getElementById('lightbox');
    var objCaption = document.getElementById('lightboxCaption');
    var objImage = document.getElementById('lightboxImage');
    var objLoadingImage = document.getElementById('loadingImage');
    var objLightboxDetails = document.getElementById('lightboxDetails');

    
    var arrayPageSize = getPageSize();
    var arrayPageScroll = getPageScroll();

    // center loadingImage if it exists
    if (objLoadingImage) {
        objLoadingImage.style.top = (arrayPageScroll[1] + ((arrayPageSize[3] - 35 - objLoadingImage.height) / 2) + 'px');
        objLoadingImage.style.left = (((arrayPageSize[0] - 20 - objLoadingImage.width) / 2) + 'px');
        objLoadingImage.style.display = 'block';
    }

    // set height of Overlay to take up whole page and show
    objOverlay.style.height = (arrayPageSize[1] + 'px');
    objOverlay.style.display = 'block';

    // preload image
    imgPreload = new Image();

    imgPreload.onload=function(){
        objImage.src = objLink.href;

        // center lightbox and make sure that the top and left values are not negative
        // and the image placed outside the viewport
        var lightboxTop = arrayPageScroll[1] + ((arrayPageSize[3] - 35 - imgPreload.height) / 2);
        var lightboxLeft = ((arrayPageSize[0] - 20 - imgPreload.width) / 2);
        
        objLightbox.style.top = (lightboxTop < 0) ? "0px" : lightboxTop + "px";
        objLightbox.style.left = (lightboxLeft < 0) ? "0px" : lightboxLeft + "px";


        objLightboxDetails.style.width = imgPreload.width + 'px';
        
        if(objLink.getAttribute('title')){
            objCaption.style.display = 'block';
            //objCaption.style.width = imgPreload.width + 'px';
            objCaption.innerHTML = objLink.getAttribute('title');
        } else {
            objCaption.style.display = 'none';
        }
        
        // A small pause between the image loading and displaying is required with IE,
        // this prevents the previous image displaying for a short burst causing flicker.
        if (navigator.appVersion.indexOf("MSIE")!=-1){
            pause(250);
        } 

        if (objLoadingImage) {  objLoadingImage.style.display = 'none'; }

        // Hide select boxes as they will 'peek' through the image in IE
        selects = document.getElementsByTagName("select");
        for (i = 0; i != selects.length; i++) {
                selects[i].style.visibility = "hidden";
        }

    
        objLightbox.style.display = 'block';

        // After image is loaded, update the overlay height as the new image might have
        // increased the overall page height.
        arrayPageSize = getPageSize();
        objOverlay.style.height = (arrayPageSize[1] + 'px');
        
        // Check for 'x' keypress
        listenKey();

        return false;
    }

    imgPreload.src = objLink.href;
    
}





//
// hideLightbox()
//
function hideLightbox()
{
    // get objects
    objOverlay = document.getElementById('overlay');
    objLightbox = document.getElementById('lightbox');

    // hide lightbox and overlay
    objOverlay.style.display = 'none';
    objLightbox.style.display = 'none';

    // make select boxes visible
    selects = document.getElementsByTagName("select");
    for (i = 0; i != selects.length; i++) {
        selects[i].style.visibility = "visible";
    }

    // disable keypress listener
    document.onkeypress = '';
}




//
// initLightbox()
// Function runs on window load, going through link tags looking for rel="lightbox".
// These links receive onclick events that enable the lightbox display for their targets.
// The function also inserts html markup at the top of the page which will be used as a
// container for the overlay pattern and the inline image.
//
function initLightbox()
{
    
    if (!document.getElementsByTagName){ return; }
    var anchors = document.getElementsByTagName("a");

    // loop through all anchor tags
    for (var i=0; i<anchors.length; i++){
        var anchor = anchors[i];

        if (anchor.getAttribute("href") && (anchor.getAttribute("rel") == "lightbox")){
            anchor.onclick = function () {showLightbox(this); return false;}
        }
    }

    // the rest of this code inserts html at the top of the page that looks like this:
    //
    // <div id="overlay">
    //      <a href="#" onclick="hideLightbox(); return false;"><img id="loadingImage" /></a>
    //  </div>
    // <div id="lightbox">
    //      <a href="#" onclick="hideLightbox(); return false;" title="Click anywhere to close image">
    //          <img id="closeButton" />        
    //          <img id="lightboxImage" />
    //      </a>
    //      <div id="lightboxDetails">
    //          <div id="lightboxCaption"></div>
    //          <div id="keyboardMsg"></div>
    //      </div>
    // </div>
    
    var objBody = document.getElementsByTagName("body").item(0);
    
    // create overlay div and hardcode some functional styles (aesthetic styles are in CSS file)
    var objOverlay = document.createElement("div");
    objOverlay.setAttribute('id','overlay');
    objOverlay.onclick = function () {hideLightbox(); return false;}
    objOverlay.style.display = 'none';
    objOverlay.style.position = 'absolute';
    objOverlay.style.top = '0';
    objOverlay.style.left = '0';
    objOverlay.style.zIndex = '90';
    objOverlay.style.width = '100%';
    objBody.insertBefore(objOverlay, objBody.firstChild);
    
    var arrayPageSize = getPageSize();
    var arrayPageScroll = getPageScroll();

    // preload and create loader image
    var imgPreloader = new Image();
    
    // if loader image found, create link to hide lightbox and create loadingimage
    imgPreloader.onload=function(){

        var objLoadingImageLink = document.createElement("a");
        objLoadingImageLink.setAttribute('href','#');
        objLoadingImageLink.onclick = function () {hideLightbox(); return false;}
        objOverlay.appendChild(objLoadingImageLink);
        
        var objLoadingImage = document.createElement("img");
        objLoadingImage.src = loadingImage;
        objLoadingImage.setAttribute('id','loadingImage');
        objLoadingImage.style.position = 'absolute';
        objLoadingImage.style.zIndex = '150';
        objLoadingImageLink.appendChild(objLoadingImage);

        imgPreloader.onload=function(){};   //  clear onLoad, as IE will flip out w/animated gifs

        return false;
    }

    imgPreloader.src = loadingImage;

    // create lightbox div, same note about styles as above
    var objLightbox = document.createElement("div");
    objLightbox.setAttribute('id','lightbox');
    objLightbox.style.display = 'none';
    objLightbox.style.position = 'absolute';
    objLightbox.style.zIndex = '100';   
    objBody.insertBefore(objLightbox, objOverlay.nextSibling);
    
    // create link
    var objLink = document.createElement("a");
    objLink.setAttribute('href','#');
    objLink.setAttribute('title','Click to close');
    objLink.onclick = function () {hideLightbox(); return false;}
    objLightbox.appendChild(objLink);

    // preload and create close button image
    var imgPreloadCloseButton = new Image();

    // if close button image found, 
    imgPreloadCloseButton.onload=function(){

        var objCloseButton = document.createElement("img");
        objCloseButton.src = closeButton;
        objCloseButton.setAttribute('id','closeButton');
        objCloseButton.style.position = 'absolute';
        objCloseButton.style.zIndex = '200';
        objLink.appendChild(objCloseButton);

        return false;
    }

    imgPreloadCloseButton.src = closeButton;

    // create image
    var objImage = document.createElement("img");
    objImage.setAttribute('id','lightboxImage');
    objLink.appendChild(objImage);
    
    // create details div, a container for the caption and keyboard message
    var objLightboxDetails = document.createElement("div");
    objLightboxDetails.setAttribute('id','lightboxDetails');
    objLightbox.appendChild(objLightboxDetails);

    // create caption
    var objCaption = document.createElement("div");
    objCaption.setAttribute('id','lightboxCaption');
    objCaption.style.display = 'none';
    objLightboxDetails.appendChild(objCaption);

    // create keyboard message
    var objKeyboardMsg = document.createElement("div");
    objKeyboardMsg.setAttribute('id','keyboardMsg');
    objKeyboardMsg.innerHTML = 'press <a href="#" onclick="hideLightbox(); return false;"><kbd>x</kbd></a> to close';
    objLightboxDetails.appendChild(objKeyboardMsg);


}




//
// addLoadEvent()
// Adds event to window.onload without overwriting currently assigned onload functions.
// Function found at Simon Willison's weblog - http://simon.incutio.com/
//
function addLoadEvent(func)
{   
    var oldonload = window.onload;
    if (typeof window.onload != 'function'){
        window.onload = func;
    } else {
        window.onload = function(){
        oldonload();
        func();
        }
    }

}



addLoadEvent(initLightbox); // run initLightbox onLoad