/**********************************************************
 Very minorly modified from the example by Tim Taylor
 http://tool-man.org/examples/sorting.html
 
 Added Coordinate.prototype.inside( northwest, southeast );
 
 **********************************************************/

var Coordinates = {
  ORIGIN : new Coordinate(0, 0),

  northwestPosition : function(element) {
    var x = parseInt(element.style.left);
    var y = parseInt(element.style.top);

    return new Coordinate(isNaN(x) ? 0 : x, isNaN(y) ? 0 : y);
  },

  southeastPosition : function(element) {
    return Coordinates.northwestPosition(element).plus(
        new Coordinate(element.offsetWidth, element.offsetHeight));
  },

  northwestOffset : function(element, isRecursive) {
    var offset = new Coordinate(element.offsetLeft, element.offsetTop);

    if (!isRecursive) return offset;

    var parent = element.offsetParent;
    while (parent) {
      offset = offset.plus(
          new Coordinate(parent.offsetLeft, parent.offsetTop));
      parent = parent.offsetParent;
    }
    return offset;
  },

  southeastOffset : function(element, isRecursive) {
    return Coordinates.northwestOffset(element, isRecursive).plus(
        new Coordinate(element.offsetWidth, element.offsetHeight));
  },

  fixEventOld : function(event) {
    if (navigator.appName == "Microsoft Internet Explorer")
      event.windowCoordinate = new Coordinate(event.clientX+document.body.scrollLeft, event.clientY+document.body.scrollTop);
    else
      event.windowCoordinate = new Coordinate(event.clientX+window.pageXOffset, event.clientY+window.pageYOffset);
  },

  is_Safari : false,
  is_Detected : false,

  fixEvent : function(event) {
    x = 0;
    y = 0;

    if (!Coordinates.is_Detected) {
      Coordinates.is_Safari = navigator.userAgent.indexOf("Safari") != -1 ? true : false;
      Coordinates.is_Detected = true;
    }

    if (self.pageYOffset) {
      if (!Coordinates.is_Safari) {  // if safari, event already  scrolled
        x = self.pageXOffset;
        y = self.pageYOffset;
      }
    }
    else if (document.documentElement && document.documentElement.scrollTop) {
     x = document.documentElement.scrollLeft;
     y = document.documentElement.scrollTop;
    }
    else if (document.body) {
     x = document.body.scrollLeft;
     y = document.body.scrollTop;
    }

    event.windowCoordinate = new Coordinate(event.clientX+x,  event.clientY+y);
  }

};

function Coordinate(x, y) {
  this.x = x;
  this.y = y;
}

Coordinate.prototype.toString = function() {
  return "(" + this.x + "," + this.y + ")";
}

Coordinate.prototype.plus = function(that) {
  return new Coordinate(this.x + that.x, this.y + that.y);
}

Coordinate.prototype.minus = function(that) {
  return new Coordinate(this.x - that.x, this.y - that.y);
}

Coordinate.prototype.distance = function(that) {
  var deltaX = this.x - that.x;
  var deltaY = this.y - that.y;

  return Math.sqrt(Math.pow(deltaX, 2) + Math.pow(deltaY, 2));
}

Coordinate.prototype.max = function(that) {
  var x = Math.max(this.x, that.x);
  var y = Math.max(this.y, that.y);
  return new Coordinate(x, y);
}

Coordinate.prototype.constrain = function(min, max) {
  if (min.x > max.x || min.y > max.y) return this;

  var x = this.x;
  var y = this.y;

  if (min.x != null) x = Math.max(x, min.x);
  if (max.x != null) x = Math.min(x, max.x);
  if (min.y != null) y = Math.max(y, min.y);
  if (max.y != null) y = Math.min(y, max.y);

  return new Coordinate(x, y);
}

Coordinate.prototype.reposition = function(element) {
  element.style["top"] = this.y + "px";
  element.style["left"] = this.x + "px";
}

Coordinate.prototype.equals = function(that) {
  if (this == that) return true;
  if (!that || that == null) return false;

  return this.x == that.x && this.y == that.y;
}

// returns true of this point is inside specified box
Coordinate.prototype.inside = function(northwest, southeast) {
  if ((this.x >= northwest.x) && (this.x <= southeast.x) &&
    (this.y >= northwest.y) && (this.y <= southeast.y)) {
    
    return true;
  }
  return false;
}