/*************************************************************************
 This code is from Dynamic Web Coding at www.dyn-web.com
 Copyright 2004 by Sharon Paine 
 See Terms of Use at www.dyn-web.com/bus/terms.html
 regarding conditions under which you may use this code.
 This notice must be retained in the code as is!
*************************************************************************/

/*  dw_slidebar.js  version date: Feb 2004  requires dw_event.js  */

// model: Aaron Boodman's dom drag at www.youngpup.net
var dw_slidebar = {
 obj: null,
 slideDur: 500, // duration of glide onclick of track 
 init: function (bar, track, axis, x, y) {
  x = x || 0; y = y || 0;
  bar.style.left = x + "px"; bar.style.top = y + "px";
  bar.axis = axis; track.bar = bar;
  if (axis == "h") {
   bar.trkWd = track.offsetWidth; // hold for setBarSize
   bar.maxX = bar.trkWd - bar.offsetWidth - x; 
   bar.minX = x; bar.maxY = y; bar.minY = y;
  } else {
   bar.trkHt = track.offsetHeight;
   bar.maxY = bar.trkHt - bar.offsetHeight - y; 
   bar.maxX = x; bar.minX = x; bar.minY = y;
  }
  bar.on_drag_start = bar.on_drag =  bar.on_drag_end = 
  bar.on_slide_start = bar.on_slide = bar.on_slide_end = function() {}
  bar.onmousedown = this.startDrag; track.onmousedown = this.startSlide;
 },
 
 startSlide: function(e) { // called onmousedown of track 
  if ( dw_slidebar.aniTimer ) clearInterval(dw_slidebar.aniTimer);
  e = e? e: window.event;
  var bar = dw_slidebar.obj = this.bar; // i.e., track's bar
  e.offX = (typeof e.layerX != "undefined")? e.layerX: e.offsetX;
  e.offY = (typeof e.layerY != "undefined")? e.layerY: e.offsetY;
  bar.startX = parseInt(bar.style.left); bar.startY = parseInt(bar.style.top);
  if (bar.axis == "v") {
   bar.destX = bar.startX;
   bar.destY = (e.offY < bar.startY)? e.offY: e.offY - bar.offsetHeight;
   bar.destY = Math.min( Math.max(bar.destY, bar.minY), bar.maxY );
  } else {
   bar.destX = (e.offX < bar.startX)? e.offX: e.offX - bar.offsetWidth;
   bar.destX = Math.min( Math.max(bar.destX, bar.minX), bar.maxX );
   bar.destY = bar.startY;
  }
  bar.distX = bar.destX - bar.startX; bar.distY = bar.destY - bar.startY;
  dw_slidebar.per = Math.PI/(2 * dw_slidebar.slideDur);
 	dw_slidebar.slideStart = (new Date()).getTime();
  bar.on_slide_start(bar.startX, bar.startY);
 	dw_slidebar.aniTimer = setInterval("dw_slidebar.doSlide()",10);
 },
 
 doSlide: function() {
  if ( !dw_slidebar.obj ) { clearInterval(dw_slidebar.aniTimer); return; }  
  var bar = dw_slidebar.obj;   
  var elapsed = (new Date()).getTime() - this.slideStart;
 	if (elapsed < this.slideDur) {
 		var x = bar.startX + bar.distX * Math.sin(this.per*elapsed);
 		var y = bar.startY + bar.distY * Math.sin(this.per*elapsed);
   bar.style.left = x + "px"; bar.style.top = y + "px";
   bar.on_slide(x, y);
 	} else {	// if time's up
   clearInterval(this.aniTimer);
   bar.style.left = bar.destX + "px"; bar.style.top = bar.destY + "px";
   bar.on_slide_end(bar.destX, bar.destY);
   this.obj = null;
 	}
 },
 
 startDrag: function (e) { // called onmousedown of bar 
  e = dw_event.DOMit(e);
  if ( dw_slidebar.aniTimer ) clearInterval(dw_slidebar.aniTimer);
  var bar = dw_slidebar.obj = this;
  bar.downX = e.clientX; bar.downY = e.clientY;
  bar.startX = parseInt(bar.style.left);
  bar.startY = parseInt(bar.style.top);
  bar.on_drag_start(bar.startX, bar.startY);
  dw_event.add( document, "mousemove", dw_slidebar.doDrag, true );
  dw_event.add( document, "mouseup",  dw_slidebar.endDrag, true );
  e.stopPropagation();
 },

 doDrag: function (e) {
  e = e? e: window.event;
  if (!dw_slidebar.obj) return;
  var bar = dw_slidebar.obj; 
  var nx = bar.startX + e.clientX - bar.downX;
  var ny = bar.startY + e.clientY - bar.downY;
  nx = Math.min( Math.max( bar.minX, nx ), bar.maxX);
  ny = Math.min( Math.max( bar.minY, ny ), bar.maxY);
  bar.style.left = nx + "px"; bar.style.top = ny + "px";
  bar.on_drag(nx,ny);
  return false; 
 },
 
 endDrag: function () {
  dw_event.remove( document, "mousemove", dw_slidebar.doDrag, true );
  dw_event.remove( document, "mouseup",  dw_slidebar.endDrag, true );
  if ( !dw_slidebar.obj ) return; // avoid errors in ie if inappropriate selections
  dw_slidebar.obj.on_drag_end( parseInt(dw_slidebar.obj.style.left), parseInt(dw_slidebar.obj.style.top) );
  dw_slidebar.obj = null; 
 }
 
}