// Effects.js - (C) 2007 Panic Inc. / Cabel Sasser
// V2.0
//
// Used for fading / zooming effects, such as image zooming.
// Requires: EffectsHTML.js
//
// License: Not For Public Use, Yet. (Public release planned. Stay tuned.)


////////////////////////////
//
// FADE Functions
//

function fadeOut(elem) {
	if (elem.id) {
		fadeElementSetup(elem.id, 100, 0, 10);
	}
}

function fadeIn(elem) {
	if (elem.id) {
		fadeElementSetup(elem.id, 0, 100, 10);	
	}
}

// Fade: Initialize the fade function

var fadeActive = new Array();
var fadeQueue  = new Array();
var fadeTimer  = new Array();
var fadeClose  = new Array();

function fadeElementSetup(theID, fdStart, fdEnd, fdSteps, fdClose) {

	if (fadeActive[theID] == true) {
		// Already animating, queue up this command
		fadeQueue[theID] = new Array(theID, fdStart, fdEnd, fdSteps);
	} else {
		fadeSteps = fdSteps;
		fadeCurrent = 0;
		fadeAmount = (fdStart - fdEnd) / fadeSteps;
		fadeTimer[theID] = setInterval("fadeElement('"+theID+"', '"+fadeCurrent+"', '"+fadeAmount+"', '"+fadeSteps+"')", 15);
		fadeActive[theID] = true;
		if (fdClose == 1) {
			fadeClose[theID] = true;
		} else {
			fadeClose[theID] = false;
		}
	}
}

// Fade: Do the fade. This function will call itself, modifying the parameters, so
// many instances can run concurrently.

function fadeElement(theID, fadeCurrent, fadeAmount, fadeSteps) {
  
	if (fadeCurrent == fadeSteps) {

	    // We're done, so clear.
	    clearInterval(fadeTimer[theID]);
	    fadeActive[theID] = false;
	    
	    // Should we close it?
	    
	    if (fadeClose[theID] == true) {
	    	document.getElementById(theID).style.visibility = "hidden";
	    }
	    
	    // Hang on.. did a command queue while we were working? If so, make it happen now
	    
	    if (fadeQueue[theID] && fadeQueue[theID] != false) {
	    	fadeElementSetup(fadeQueue[theID][0], fadeQueue[theID][1], fadeQueue[theID][2], fadeQueue[theID][3]);
	    	fadeQueue[theID] = false;
	    }  
  
	} else {
  
		fadeCurrent++;
		
		// Set the opacity depending on if we're adding or subtracting (pos or neg)
		if (fadeAmount < 0) {
			setOpacity(Math.abs(fadeCurrent * fadeAmount), theID);
		} else {
			setOpacity(100 - (fadeCurrent * fadeAmount), theID);
		}
		
		// Keep going, and send myself the updated variables
		clearInterval(fadeTimer[theID]);
		fadeTimer[theID] = setInterval("fadeElement('"+theID+"', '"+fadeCurrent+"', '"+fadeAmount+"', '"+fadeSteps+"')", 15);
	}
}

////////////////////////////
//
// UTILITY functions
//

// Utility: Set the opacity, compatible with a number of browsers. Value from 0 to 100.

function setOpacity(opacity, theID) {

	var object = document.getElementById(theID).style;

	// If it's 100, set it to 99 for Firefox.

	if (navigator.userAgent.indexOf("Firefox") != -1) {
		if (opacity == 100) { opacity = 99.9999; } // This is majorly retarded
	}

	// Multi-browser opacity setting

	object.filter = "alpha(opacity=" + opacity + ")"; // IE/Win
	//object.KhtmlOpacity = (opacity / 100);            // Safari 1.1 or lower, Konqueror
	//object.MozOpacity = (opacity / 100);              // Older Mozilla+Firefox
	object.opacity = (opacity / 100);                 // Safari 1.2, Firefox+Mozilla

}

// Utility: Math functions for animation calucations - From http://www.robertpenner.com/easing/
//
// t = time, b = begin, c = change, d = duration
// time = current frame, begin is fixed, change is basically finish - begin, duration is fixed (frames),

function linear(t, b, c, d)
{
	return c*t/d + b;
}

function sineInOut(t, b, c, d)
{
	return -c/2 * (Math.cos(Math.PI*t/d) - 1) + b;
}

function cubicIn(t, b, c, d) {
	return c*(t/=d)*t*t + b;
}

function cubicOut(t, b, c, d) {
	return c*((t=t/d-1)*t*t + 1) + b;
}

function cubicInOut(t, b, c, d)
{
	if ((t/=d/2) < 1) return c/2*t*t*t + b;
	return c/2*((t-=2)*t*t + 2) + b;
}

function bounceOut(t, b, c, d)
{
	if ((t/=d) < (1/2.75)){
		return c*(7.5625*t*t) + b;
	} else if (t < (2/2.75)){
		return c*(7.5625*(t-=(1.5/2.75))*t + .75) + b;
	} else if (t < (2.5/2.75)){
		return c*(7.5625*(t-=(2.25/2.75))*t + .9375) + b;
	} else {
		return c*(7.5625*(t-=(2.625/2.75))*t + .984375) + b;
	}
}


// Utility: Get the size of the window, and set myWidth and myHeight

function getSize() {
	if (document.all) {
		// IE4+ or IE6+ in standards compliant 
		myWidth  = (document.documentElement.clientWidth) ? document.documentElement.clientWidth : document.body.clientWidth;
		myHeight = (document.documentElement.clientHeight) ? document.documentElement.clientHeight : document.body.clientHeight;
		myScroll = (document.documentElement.scrollTop) ? document.documentElement.scrollTop : document.body.scrollTop;
	} else {
		// Non-IE
		myWidth = window.innerWidth;
		myHeight = window.innerHeight;
		myScroll = window.pageYOffset;
	}
	
	// Core code from - quirksmode.org
    if (window.innerHeight && window.scrollMaxY) {	
        myScrollWidth = document.body.scrollWidth;
		myScrollHeight = window.innerHeight + window.scrollMaxY;
	} else if (document.body.scrollHeight > document.body.offsetHeight) { // all but Explorer Mac
		myScrollWidth = document.body.scrollWidth;
		myScrollHeight = document.body.scrollHeight;
	} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
		myScrollWidth = document.body.offsetWidth;
		myScrollHeight = document.body.offsetHeight;
	}
}

// Utility: Find the Y position of an element on a page. Return Y and X as an array

function findElementPos(elemFind)
{
	var elemX = 0;
	var elemY = 0;
	do {
		elemX += elemFind.offsetLeft;
		elemY += elemFind.offsetTop;
	} while ( elemFind = elemFind.offsetParent )

	//console.log("Found element "+elemFind+" at "+elemY+"/"+elemX);

	return Array(elemX, elemY);
}