Effect.Wave = Class.create(Effect.Base, {
  initialize: function(element) {
    this.element = $(element);
    if (!this.element) throw(Effect._elementDoesNotExistError);
    var options = Object.extend({
      x:    0,
      y:    0,
      h:	50,
      hspeed: 0.05,
      mode: 'relative',
      transition: Effect.Transitions.linear
    }, arguments[1] || { });
    this.start(options);
  },
  setup: function() {
    this.element.makePositioned();
    this.originalLeft = parseFloat(this.element.getStyle('left') || '0');
    this.originalTop  = parseFloat(this.element.getStyle('top')  || '0');
    if (this.options.mode == 'absolute') {
      this.options.x = this.options.x - this.originalLeft;
      this.options.y = this.options.y - this.originalTop;
    }
  },
  update: function(position) {
    this.element.setStyle({
      left: (this.options.x  * position + this.originalLeft).round() + 'px',
      top: (Math.sin(this.options.y * position * this.options.hspeed) * this.options.h) + (this.options.y  * position + this.originalTop) + 'px'
    });
  }
});