// JavaScript Document
var TimeToFade = 1000.0;
var Fully_Opaque = 2;
var Fully_Transparent = -2;
var Fading_to_Opaque = 1;
var Fading_to_Transparent = -1;

function switch_image_pair(new_ImgPairNum, target_image, fade_eid){
	fade_out(fade_eid, null);
	GetAfter(new_ImgPairNum, target_image);
	ImagePairNum = new_ImgPairNum;
	fade_in(fade_eid);
}

function GetBefore(ImagePairNum, target_image){
	var newImg = (ImagePairNum*2);
	
	document.images[target_image].src = img[newImg].src;
	document.images[target_image].width = img[newImg].width;
	document.images[target_image].height = img[newImg].height;
	imgNumber = newImg;
}

function GetAfter(ImagePairNum, target_image){
	var newImg = (ImagePairNum*2)+1;

	document.images[target_image].src = img[newImg].src;
	document.images[target_image].width = img[newImg].width;
	document.images[target_image].height = img[newImg].height;
	imgNumber = newImg;
}


function switch_image(new_imgNumber, target_image, fade_eid){
	fade_out(fade_eid,null);
	document.images[target_image].src = img[new_imgNumber].src;
	document.images[target_image].width = img[new_imgNumber].width;
	document.images[target_image].height = img[new_imgNumber].height;
	imgNumber = new_imgNumber;
	fade_in(fade_eid);
}

function NextImage()
{
	fade_out('mainpic',null);
	imgNumber++;
    if (imgNumber == NumberOfImages)
        imgNumber = 0;
    document.images["Portfolio_Main"].src = img[imgNumber].src;
	document.images["Portfolio_Main"].width = img[imgNumber].width;
	document.images["Portfolio_Main"].height = img[imgNumber].height;
	fade_in('mainpic');
}

function PreviousImage()
{
	fade_out('mainpic',null);
    imgNumber--;
    if (imgNumber < 0)
        imgNumber = NumberOfImages - 1;
    document.images["Portfolio_Main"].src = img[imgNumber].src;
	document.images["Portfolio_Main"].width = img[imgNumber].width;
	document.images["Portfolio_Main"].height = img[imgNumber].height;
	fade_in('mainpic');
}

function fade_out(eid, next_page)
{
  var element = document.getElementById(eid);
  if(element == null)
    return;

  element.FadeState = Fading_to_Transparent;
  element.FadeTimeLeft = TimeToFade;
  setTimeout("animateFade_out(" + new Date().getTime() + ",'" + eid + "','" + next_page + "')", 33);
}

function animateFade_out(lastTick, eid, next_page)
{  

  var curTick = new Date().getTime();
  var elapsedTicks = curTick - lastTick;
  
  var element = document.getElementById(eid);

  if(element.FadeState != Fading_to_Transparent)
	return; 
  
  if(element.FadeTimeLeft <= elapsedTicks)
  {
    element.style.opacity = '0';
    element.style.filter = 'alpha(opacity = ' + 0 + ')';
    element.FadeState = Fully_Transparent;
	if(next_page != "null"){	
		window.document.location = next_page;
	}
	return;
  }
 
  element.FadeTimeLeft -= elapsedTicks;
  var newOpVal = element.FadeTimeLeft/TimeToFade;

  element.style.opacity = newOpVal;
  element.style.filter = 'alpha(opacity = ' + (newOpVal*100) + ')';
  
  setTimeout("animateFade_out(" + curTick + ",'" + eid + "','" + next_page + "')", 33);
}

function fade_in(eid)
{
  var element = document.getElementById(eid);
  if(element == null)
    return;

  element.style.opacity = '0';
  element.style.filter = 'alpha(opacity = ' + 0 + ')';
  element.FadeTimeLeft = TimeToFade;
  element.FadeState = Fading_to_Opaque;
  setTimeout("animateFade_in(" + new Date().getTime() + ",'" + eid + "')", 33);
}

function animateFade_in(lastTick, eid)
{  
  var curTick = new Date().getTime();
  var elapsedTicks = curTick - lastTick;
  
  var element = document.getElementById(eid);
 
  if(element.FadeTimeLeft <= elapsedTicks)
  {
    element.style.opacity = '1';
    element.style.filter = 'alpha(opacity = ' + 100 + ')';
    element.FadeState = Fully_Opaque;
	return;
  }
 
  element.FadeTimeLeft -= elapsedTicks;
  var newOpVal = element.FadeTimeLeft/TimeToFade;
  newOpVal = 1 - newOpVal;

  element.style.opacity = newOpVal;
  element.style.filter = 'alpha(opacity = ' + (newOpVal*100) + ')';
  
  setTimeout("animateFade_in(" + curTick + ",'" + eid + "')", 33);
}