// JavaScript Document
/* =======================================================
 * 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 { width:' + width + 'px; height:' + height + 'px; clip:rect(0 ' + width + ' ' + height + ' 0); overflow:hidden; }');
    d.write('#' + this.id + 'Container, #' + this.id + 'Content { position:relative; }');
    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);
};

var test = new ypSimpleScroll("myScroll", 0, 0, 740, 80, 100);
img1 = new Image();
img1.src = 'images/loader_gray.gif';