Mask.js

/*
---

script: Mask.js

name: Mask

description: Creates a mask element to cover another.

license: MIT-style license

authors:
  - Aaron Newton

requires:
  - Core/Options
  - Core/Events
  - Core/Element.Event
  - /Class.Binds
  - /Element.Position
  - /IframeShim

provides: [Mask]

...
*/

var Mask = new Class({

	Implements: [Options, Events],

	Binds: ['position'],

	options: {/*
		onShow: function(){},
		onHide: function(){},
		onDestroy: function(){},
		onClick: function(event){},
		inject: {
			where: 'after',
			target: null,
		},
		hideOnClick: false,
		id: null,
		destroyOnHide: false,*/
		style: {},
		'class': 'mask',
		maskMargins: false,
		useIframeShim: true,
		iframeShimOptions: {}
	},

	initialize: function(target, options){
		this.target = document.id(target) || document.id(document.body);
		this.target.store('mask', this);
		this.setOptions(options);
		this.render();
		this.inject();
	},

	render: function(){
		this.element = new Element('div', {
			'class': this.options['class'],
			id: this.options.id || 'mask-' + String.uniqueID(),
			styles: Object.merge({}, this.options.style, {
				display: 'none'
			}),
			events: {
				click: function(event){
					this.fireEvent('click', event);
					if (this.options.hideOnClick) this.hide();
				}.bind(this)
			}
		});

		this.hidden = true;
	},

	toElement: function(){
		return this.element;
	},

	inject: function(target, where){
		where = where || (this.options.inject ? this.options.inject.where : '') || this.target == document.body ? 'inside' : 'after';
		target = target || (this.options.inject && this.options.inject.target) || this.target;

		this.element.inject(target, where);

		if (this.options.useIframeShim){
			this.shim = new IframeShim(this.element, this.options.iframeShimOptions);

			this.addEvents({
				show: this.shim.show.bind(this.shim),
				hide: this.shim.hide.bind(this.shim),
				destroy: this.shim.destroy.bind(this.shim)
			});
		}
	},

	position: function(){
		this.resize(this.options.width, this.options.height);

		this.element.position({
			relativeTo: this.target,
			position: 'topLeft',
			ignoreMargins: !this.options.maskMargins,
			ignoreScroll: this.target == document.body
		});

		return this;
	},

	resize: function(x, y){
		var opt = {
			styles: ['padding', 'border']
		};
		if (this.options.maskMargins) opt.styles.push('margin');

		var dim = this.target.getComputedSize(opt);
		if (this.target == document.body){
			this.element.setStyles({width: 0, height: 0});
			var win = window.getScrollSize();
			if (dim.totalHeight < win.y) dim.totalHeight = win.y;
			if (dim.totalWidth < win.x) dim.totalWidth = win.x;
		}
		this.element.setStyles({
			width: Array.pick([x, dim.totalWidth, dim.x]),
			height: Array.pick([y, dim.totalHeight, dim.y])
		});

		return this;
	},

	show: function(){
		if (!this.hidden) return this;

		window.addEvent('resize', this.position);
		this.position();
		this.showMask.apply(this, arguments);

		return this;
	},

	showMask: function(){
		this.element.setStyle('display', 'block');
		this.hidden = false;
		this.fireEvent('show');
	},

	hide: function(){
		if (this.hidden) return this;

		window.removeEvent('resize', this.position);
		this.hideMask.apply(this, arguments);
		if (this.options.destroyOnHide) return this.destroy();

		return this;
	},

	hideMask: function(){
		this.element.setStyle('display', 'none');
		this.hidden = true;
		this.fireEvent('hide');
	},

	toggle: function(){
		this[this.hidden ? 'show' : 'hide']();
	},

	destroy: function(){
		this.hide();
		this.element.destroy();
		this.fireEvent('destroy');
		this.target.eliminate('mask');
	}

});

Element.Properties.mask = {

	set: function(options){
		var mask = this.retrieve('mask');
		if (mask) mask.destroy();
		return this.eliminate('mask').store('mask:options', options);
	},

	get: function(){
		var mask = this.retrieve('mask');
		if (!mask){
			mask = new Mask(this, this.retrieve('mask:options'));
			this.store('mask', mask);
		}
		return mask;
	}

};

Element.implement({

	mask: function(options){
		if (options) this.set('mask', options);
		this.get('mask').show();
		return this;
	},

	unmask: function(){
		this.get('mask').hide();
		return this;
	}

});