/*
---
 
name: Fx.Text
 
description: Effect to animated replace the text of an element.

authors: Dipl.-Ing. (FH) André Fiedler <kontakt@visualdrugs.net>

copyright: Copyright (c) 2010 Dipl.-Ing. (FH) André Fiedler <kontakt@visualdrugs.net>
 
license: MIT-style license.

version: 1.2.1
 
requires: Core/1.2.4: Fx
 
provides: Fx.Text
 
...
*/

Fx.Text = new Class({

    Extends: Fx,
    
    initialize: function(element, options){
        this.element = this.subject = document.id(element);
        this.parent(options);
    },
    
    set: function(now){
        this.element.set('text', now);
        return this;
    },
    
    step: function(){
        if (!this.to) {
            this.to = this.from;
            this.from = this.element.get('text', '');
        }
        return this.parent();
    },
    
    compute: function(from, to, delta){
        var l = Math.round(to.length * delta);
        var r = Math.round((from.length - to.length) * delta);
        return to.substr(0, l) + from.substr(l, from.length - l - r);
    }
});