var activeImage = false;
var imageGalleryTopPos = false;
var imageGalleryHeight = false;
var imageGalleryObj = false;
var maxGalleryXPos = false;
var slideSpeed = 0;
var baseSpeed = 5;

function startSlide(e) {
  if(document.all) {
    e = event;
  }
  var id = this.id;

  if(this.id == 'arrow_inf') {
    slideSpeedMultiply = Math.floor((e.clientX - this.offsetTop) / 5);
    slideSpeed = -1 * slideSpeedMultiply;
    slideSpeed = Math.max(-baseSpeed, slideSpeed);
  } else {
    slideSpeedMultiply = baseSpeed - Math.floor((e.clientX - this.offsetTop) / 5);
    slideSpeed = 1 * slideSpeedMultiply;
    slideSpeed = Math.min(baseSpeed, slideSpeed);
    if(slideSpeed < 0) {
      slideSpeed = baseSpeed;
    }
  }
}

function releaseSlide() {
  var id = this.id;
  slideSpeed = 0;
}

function gallerySlide() {
  if(slideSpeed != 0) {
    var topPos = imageGalleryObj.offsetTop;
    topPos = topPos/1 + slideSpeed;
    if(topPos > maxGalleryXPos) {
      topPos = maxGalleryXPos;
      slideSpeed = 0;
    }
    if(topPos < minGalleryXPos) {
      topPos = minGalleryXPos;
      slideSpeed = 0;
    }
    imageGalleryObj.style.top = topPos + 'px';
  }
  setTimeout('gallerySlide()', 20);
}

/**
 * initSlideShow.
 * Inicializa el componente js para ver la tira de imagenes.
 *
 * @param int alt Altura del div de scroll en px
 */
function initSlideShow(alt) {
  $('arrow_sup').onmousemove = startSlide;
  $('arrow_sup').onmouseout = releaseSlide;
  $('arrow_inf').onmousemove = startSlide;
  $('arrow_inf').onmouseout = releaseSlide;
  imageGalleryObj = $('me_gustan_slider');
  imageGalleryTopPos = imageGalleryObj.offsetTop;
  imageGalleryHeight = 0;
  maxGalleryXPos = 0;
  minGalleryXPos = -alt;
  gallerySlide();
}