/*

    Lightbox JS: Fullsize Image Overlays 

    by Lokesh Dhakar - http://www.huddletogether.com



    For more information on this script, visit:

    http://huddletogether.com/projects/lightbox/



    Script featured on Dynamic Drive code library Jan 24th, 06':

    http://www.dynamicdrive.com



    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'; }

        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';

    

    // 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 = '';

    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