// Make an HTML element fly in from the top or bottom.

// Includes inertia!

// vB, don't even try. It's GPL like the rest of Enano. I know you're jealous. >:)

var fly_in_cache = new Object();

var FI_TOP = 1;

var FI_BOTTOM = 2;

var FI_IN = 1;

var FI_OUT = 2;

var FI_UP = 1;

var FI_DOWN = 2;

// increase to slow down transitions (for debug)

var FI_MULTIPLIER = 1;

/**

 * You can thank Robert Penner for the math used here. Ported from an ActionScript class.

 * License: Modified BSD license <http://www.robertpenner.com/easing_terms_of_use.html>

 */

// Effects code - don't bother changing these formulas

var Back = {

	easeOut: function(t, b, c, d, s)

	{

		if (s == undefined) s = 1.70158;

		return c * ( ( t=t/d-1 ) * t * ( ( s + 1 ) * t + s) + 1) + b;

	},

	easeIn: function (t, b, c, d, s)

	{

		if (s == undefined) s = 1.70158;

		return c * ( t/=d ) * t * ( ( s + 1 ) * t - s) + b;

	},

	easeInOut: function (t, b, c, d, s)

	{

		if (s == undefined) s = 1.70158; 

		if ((t /= d/2) < 1) 

		{

			return c/2*(t*t*(((s*=(1.525))+1)*t - s)) + b;

		}

		return c/2*((t-=2)*t*(((s*=(1.525))+1)*t + s) + 2) + b;

	}

}

// This should be set to the class name of the effect you want.

var GlideEffect = Back;

// Placeholder functions, to make organization a little easier :-)

function fly_in_top(element, nofade, height_taken_care_of)

{

	return fly_core(element, nofade, FI_TOP, FI_IN, height_taken_care_of);

}

function fly_in_bottom(element, nofade, height_taken_care_of)

{

	return fly_core(element, nofade, FI_BOTTOM, FI_IN, height_taken_care_of);

}

function fly_out_top(element, nofade, height_taken_care_of)

{

	return fly_core(element, nofade, FI_TOP, FI_OUT, height_taken_care_of);

}

function fly_out_bottom(element, nofade, height_taken_care_of)

{

	return fly_core(element, nofade, FI_BOTTOM, FI_OUT, height_taken_care_of);

}

function fly_core(element, nofade, origin, direction, height_taken_care_of)

{

	if ( !element || typeof(element) != 'object' )

		return false;

	// force to array

	if ( !element.length )

		element = [ element ];

	// target dimensions

	var top, left;

	// initial dimensions

	var topi, lefti;

	// current dimensions

	var topc, leftc;

	// screen dimensions

	var w = getWidth();

	var h = getHeight();

	var y = parseInt ( getScrollOffset() );

	// temp vars

	var dim, off, diff, dist, ratio, opac_factor;

	// setup element

	for ( var i = 0; i < element.length; i++ )

		element[i].style.position = 'absolute';

	dim = [ $dynano(element[0]).Height(), $dynano(element[0]).Width() ];

	off = [ $dynano(element[0]).Top(), $dynano(element[0]).Left() ];

	if ( height_taken_care_of )

	{

		top = off[0];

		left = off[1];

	}

	else

	{

		top  = Math.round(( h / 2 ) - ( dim[0] / 2 )) + y; // - ( h / 4 ));

		left = Math.round(( w / 2 ) - ( dim[1] / 2 ));

	}

	// you can change this around to get it to fly in from corners or be on the left/right side

	lefti = left;

	// calculate first frame Y position

	if ( origin == FI_TOP && direction == FI_IN )

	{

		topi = 0 - dim[0] + y;

	}

	else if ( origin == FI_TOP && direction == FI_OUT )

	{

		topi = top;

		top = 0 - dim[0] + y;

	}

	else if ( origin == FI_BOTTOM && direction == FI_IN )

	{

		topi = h + y;

	}

	else if ( origin == FI_BOTTOM && direction == FI_OUT )

	{

		topi = top;

		top = h + y;

	}

	var abs_dir = ( ( origin == FI_TOP && direction == FI_IN ) || ( origin == FI_BOTTOM && direction == FI_OUT ) ) ? FI_DOWN : FI_UP;

	var diff_top = top - topi;

	var diff_left = left - lefti;

	var frames = 100;

	var timeout = 0;

	var timerstep = 8 * FI_MULTIPLIER;

	// cache element so it can be changed from within setTimeout()

	var rand_seed = Math.floor(Math.random() * 1000000);

	fly_in_cache[rand_seed] = element;

	for ( var i = 0; i < frames; i++ )

	{

		topc = GlideEffect.easeInOut(i, topi, diff_top, frames);

		leftc = GlideEffect.easeInOut(i, lefti, diff_left, frames);

		var code = 'var element = fly_in_cache[' + rand_seed + '];' + "\n";

		code +=    'for ( var i = 0; i < element.length; i++ )' + "\n";

		code +=    '{' + "\n";

		code +=    '  element[i].style.top = "' + topc + 'px";' + "\n";

		if ( !height_taken_care_of )

			code +=  '  element[i].style.left = "' + leftc + 'px";' + "\n";

		code +=    '}';

		setTimeout(code, timeout);

		timeout += timerstep;

		var ratio = i / frames;

		if ( !nofade )

		{

			// handle fade

			var opac_factor = ratio * 100;

			if ( direction == FI_OUT )

				opac_factor = 100 - opac_factor;

			var code = 'var element = fly_in_cache[' + rand_seed + '];' + "\n";

			code +=    'for ( var i = 0; i < element.length; i++ )' + "\n";

			code +=    '{' + "\n";

			code +=    '  domObjChangeOpac(' + opac_factor + ', element[i]);' + "\n";

			code +=    '}';

			setTimeout(code, timeout);

		}

	}

	// old framestepper code removed from here in Loch Ness

	timeout += timerstep;

	return timeout;

}

function abs(i)

{

	if ( isNaN(i) )

		return i;

	return ( i < 0 ) ? ( 0 - i ) : i;

}