/*************************************************************************

  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;  

  }

  

}