// JavaScript to do vertical scroll on mouseover



/* =======================================================

 * ypSimpleScroll

 * 3/11/2001

 * 

// dhtml scrolling panel featuring scrolling in any

// direction, smooth frame-dropping animation, and a

// few other goodies.

//

// 3/25/2001

// added scrolling in any direction and initTop, initLeft

// constructor parameters - with only 1k...

//

// 3/30/2001

// fixed bug that occured when if you called scrollTo( )

// and the new position was the same as the current

// position. that was stupid.

//

// 4/02/2001

// small bug fix - on some browsers, on slow connections

// the script would not run at all. to be sure the doc

// is done loading before .load() is called, the author

// must now call the .load() method in the onload handler

// for the page.

//

// 8/22/2001

// if you tried to scroll before page was loaded it threw

// an error. this should be fixed now.

// 

//

 * http://www.youngpup.net/

//

// =======================================================

// ypSimpleScroll(  id, left, top, width, height, speed, 

//          contentWidth, initScrollLeft, 

//          initScrollTop  )

//

// last three parameters are optional.

 * ======================================================= */





// basic methods.

ypSimpleScroll.prototype.scrollNorth = function() { this.startScroll(90) }

ypSimpleScroll.prototype.scrollSouth = function() { this.startScroll(270)  }

ypSimpleScroll.prototype.scrollWest  = function() { this.startScroll(180) }

ypSimpleScroll.prototype.scrollEast  = function() { this.startScroll(0)   }





// start scrolling in an arbitrary direction, with an optional arbitrary speed.

// if no speed is provided, the default speed from the constructor parameter is used.

ypSimpleScroll.prototype.startScroll = function(deg, speed) {

  if (this.loaded)

  {

    if (this.aniTimer) window.clearTimeout(this.aniTimer)

    this.overrideScrollAngle(deg)



    this.speed    = speed ? speed : this.origSpeed

    this.lastTime = (new Date()).getTime() - this.y.minRes

    this.aniTimer = window.setTimeout(this.gRef + ".scroll()", this.y.minRes)

  }

}



// kills pending calls to .scroll(), resets speed

ypSimpleScroll.prototype.endScroll = function() {

  if (this.loaded)

  {

    window.clearTimeout(this.aniTimer)

    this.aniTimer = 0;

    this.speed = this.origSpeed

  }

}



// override the current angle from startScroll() with a new angle

// this method should not be used with scrollTo() because it will

// override the angle created by the first two params to scrollTo().

ypSimpleScroll.prototype.overrideScrollAngle = function(deg) {

  if (this.loaded)

  {

    deg = deg % 360

    if (deg % 90 == 0) {

      var cos = deg == 0  ? 1 : deg == 180 ? -1 : 0

      var sin = deg == 90 ? -1 : deg == 270 ? 1 : 0

    } else {

      var angle = deg * Math.PI / 180

      var cos   = Math.cos(angle)

      var sin   = Math.sin(angle)

      sin = -sin

    }

    this.fx = cos / (Math.abs(cos) + Math.abs(sin))

    this.fy = sin / (Math.abs(cos) + Math.abs(sin))

    this.stopH = deg == 90 || deg == 270 ? this.scrollLeft : deg < 90 || deg > 270 ? this.scrollW : 0

    this.stopV = deg == 0 || deg == 180 ? this.scrollTop : deg < 180 ? 0 : this.scrollH

  }

}



// override the speed for the current scroll.

// should not be used with scrollTo, unless you want to 

// override the speed computed from the aniLen param of scrollTo()

ypSimpleScroll.prototype.overrideScrollSpeed = function(speed) {

  if (this.loaded) this.speed = speed

}



// scroll to an arbitrary position in two dimensions over in

// an arbitrary lenth of time.

ypSimpleScroll.prototype.scrollTo = function(stopH, stopV, aniLen) {

  if (this.loaded)

  {

    if (stopH != this.scrollLeft || stopV != this.scrollTop) {

      if (this.aniTimer) window.clearTimeout(this.aniTimer)

      this.lastTime = (new Date()).getTime()

      var dx = Math.abs(stopH - this.scrollLeft)

      var dy = Math.abs(stopV - this.scrollTop)

      var d = Math.sqrt(Math.pow(dx,2) + Math.pow(dy,2))

      this.fx = (stopH - this.scrollLeft) / (dx + dy)

      this.fy = (stopV - this.scrollTop) / (dx + dy)

      this.stopH = stopH

      this.stopV = stopV

      this.speed = d / aniLen * 1000

      window.setTimeout(this.gRef + ".scroll()", this.y.minRes)

    }

  }

}



// jump to an arbitrary position in two dimensions.

ypSimpleScroll.prototype.jumpTo = function(nx, ny) { 

  if (this.loaded)

  {

    nx = Math.min(Math.max(nx, 0), this.scrollW)

    ny = Math.min(Math.max(ny, 0), this.scrollH)

    this.scrollLeft = nx

    this.scrollTop = ny

    if (this.y.ns4)this.content.moveTo(-nx, -ny)

    else {

      this.content.style.left = -nx + "px"

      this.content.style.top = -ny + "px"

    }

  }

}







// =========================================================================

// =============================== private =================================

// =========================================================================



ypSimpleScroll.minRes = 10

ypSimpleScroll.ie  = document.all ? 1 : 0

ypSimpleScroll.ns4 = document.layers ? 1 : 0

ypSimpleScroll.dom = document.getElementById ? 1 : 0

ypSimpleScroll.mac = navigator.platform == "MacPPC"

ypSimpleScroll.mo5 = document.getElementById && !document.all ? 1 : 0



// recursively calls itself to animate

ypSimpleScroll.prototype.scroll = function() {

  this.aniTimer = window.setTimeout(this.gRef + ".scroll()", this.y.minRes)

  var nt = (new Date()).getTime()

  var d = Math.round((nt - this.lastTime) / 1000 * this.speed)

  if (d > 0)

  {

    var nx = d * this.fx + this.scrollLeft

    var ny = d * this.fy + this.scrollTop



    var xOut = (nx >= this.scrollLeft && nx >= this.stopH) || (nx <= this.scrollLeft && nx <= this.stopH)

    var yOut = (ny >= this.scrollTop && ny >= this.stopV)  || (ny <= this.scrollTop && ny <= this.stopV)

    //window.status = nx + " " + this.fx + " " + this.scrollLeft + " " + this.stopH + " | " + ny + " " + this.fy + " " + this.scrollTop + " " + this.stopV + " : " + d

    if (nt - this.lastTime != 0 &&

      ((this.fx == 0 && this.fy == 0) ||

       (this.fy == 0 && xOut) ||

       (this.fx == 0 && yOut) ||

       (this.fx != 0 && this.fy != 0 && xOut && yOut)))

    {

      this.jumpTo(this.stopH, this.stopV)

      this.endScroll()

    }

    else {

      this.jumpTo(nx, ny)

      this.lastTime = nt

    }

  }

}



// constructor

function ypSimpleScroll(id, left, top, width, height, speed, contentWidth, initLeft, initTop)

{

  var y = this.y = ypSimpleScroll

  if (!initLeft)     initLeft     = 0

  if (!initTop)      initTop      = 0

  if (!contentWidth) contentWidth = width



  // fix for netscape4 first-page bug.

  if (document.layers && !y.ns4) history.go(0)



  if (y.ie || y.ns4 || y.dom) {

    this.loaded    = false

    this.id      = id

    this.origSpeed  = speed

    this.aniTimer  = false

    this.op      = ""

    this.lastTime  = 0

    this.clipH    = height

    this.clipW    = width

    this.scrollTop  = initTop

    this.scrollLeft  = initLeft



    // global reference to this object

    this.gRef = "ypSimpleScroll_"+id

    eval(this.gRef+"=this")



    var d = document

    d.write('<style type="text/css">')

    d.write('#' + this.id + 'Container { left:' + left + 'px; top:' + top + 'px; width:' + width + 'px; height:' + height + 'px; clip:rect(0 ' + width + ' ' + height + ' 0); overflow:hidden; }')

    d.write('#' + this.id + 'Container, #' + this.id + 'Content { position:absolute; }')

    d.write('#' + this.id + 'Content { left:' + (-initLeft) + 'px; top:' + (-initTop) + 'px; width:' + contentWidth + 'px; }')

    d.write('</style>')

  }

}



// once the nceesary objects are present in the DOM, this gathers some info about them.

ypSimpleScroll.prototype.load = function() {

  var d, lyrId1, lyrId2



  d = document

  lyrId1 = this.id + "Container"

  lyrId2 = this.id + "Content"



  this.container  = this.y.dom ? d.getElementById(lyrId1) : this.y.ie ? d.all[lyrId1] : d.layers[lyrId1]

  this.content  = obj2 = this.y.ns4 ? this.container.layers[lyrId2] : this.y.ie ? d.all[lyrId2] : d.getElementById(lyrId2)

  this.docH    = Math.max(this.y.ns4 ? this.content.document.height : this.content.offsetHeight, this.clipH)

  this.docW    = Math.max(this.y.ns4 ? this.content.document.width  : this.content.offsetWidth,  this.clipW)

  this.scrollH  = this.docH - this.clipH

  this.scrollW  = this.docW - this.clipW

  this.loaded    = true

  this.scrollLeft = Math.max(Math.min(this.scrollLeft, this.scrollW),0)

  this.scrollTop  = Math.max(Math.min(this.scrollTop, this.scrollH),0)

  this.jumpTo(this.scrollLeft, this.scrollTop)

}