// Basic Element Animator (21-December-2008) DRAFT
// by Vic Phillips http://www.vicsjavascripts.org.uk

// To progressively change the Left, Top, Width, Height or Opacity of an element over a specified period of time.
// With three types of progression 'sin' and 'cos' and liner.

// **** Application Notes

// **** The HTML Code
//
// when moving an element the inline or class rule style position of the element should be assigned as
// 'position:relative;' or 'position:absolute;'.
//
// The element would normally be assigned a unique ID name.
//

// **** Executing the Effect(Script)
//
// The effect is executed by an event call to function 'zxcBAnimator('left','tst1',20,260,2000);'
// where:
// parameter 0 = the mode(see Note 1).                                                                     (string)
// parameter 1 = the unique ID name or element object.                                                     (string or element object)
// parameter 2 = the start position of the effect.                                                         (digits, for opacity minimum 0, maximum 100)
// parameter 3 = the finish position of the effect.                                                        (digits, for opacity minimum 0, maximum 100)
// parameter 4 = (optional) period of time between the start and finish of the effect in milliseconds.     (digits or defaults to 2000 milliSeconds)
//
//  Note 1:  The default units(excepting opacity) are 'px'.
//  Note 2:  Examples modes: 'left', 'top', 'width', 'height', 'opacity.
//           For hyphenated modes, the first character after the hyphen must be upper case, all others lower case.
//  Note 3:  To 'toggle' the effect include '#' in parameter 0.
//           The first call will set the toggle parameters.
//           Subsequent calls with '#' in parameter 0 and the same start and finish parameters will 'toggle' the effect.
//  Note 4:  The function may be re-executed with a different set of parameters (start/finish time or period)
//           whenever required, say from an onclick/mouseover/out event.
//           The period parameter will be retained unless re-specified.
//  Note 5: there are three types of progression 'sin' and 'cos' and liner.
//                'sin' progression starts fast and ends slow.
//                'cos' progression starts slow and ends fast.
//          Once set the type of change will be retained until respecified.
//
// **** Advanced Applications
//
//  It may be required to access the current value of the effect.
//  The element effect is accessible from the element property
//  element effect = elementobject[mode.replace(/[-#]/g,'')+'oop'];
//  where mode is parameter 0 of the initial call.
//  An array storing the current, start and finish values of the element effect may be accessed
//  from the element effect.data as fields 0, 1 and 2 respectively
//

// **** General
//
// All variable, function etc. names are prefixed with 'zxc' to minimise conflicts with other JavaScripts.
// These characters may be changed to characters of choice using global find and replace.
//
// The Functional Code(about 2K) is best as an External JavaScript.
//
// Tested with IE7 and Mozilla FireFox on a PC.
//



// **** Functional Code - NO NEED to Change


function zxcBAnimator(mde,obj,srt,fin,time,zxccurve){
 if (typeof(obj)=='string'){ obj=document.getElementById(obj); }
 if (!obj||(!srt&&!fin)) return;
 var oop=obj[mde.replace(/[-#]/g,'')+'oop'];
 if (oop){
  clearTimeout(oop.to);
  if (oop.srtfin[0]==srt&&oop.srtfin[1]==fin&&mde.match('#')) oop.update([oop.data[0],(oop.srtfin[0]==oop.data[2])?fin:srt],time,zxccurve);
  else oop.update([srt,fin],time);
 }
 else obj[mde.replace(/[-#]/g,'')+'oop']=new zxcBAnimatorOOP(mde,obj,srt,fin,time,zxccurve);
}

function zxcBAnimatorOOP(mde,obj,srt,fin,time,zxccurve){
 this.srtfin=[srt,fin];
 this.to=null;
 this.obj=obj;
 this.mde=mde.replace(/[-#]/g,'');
 this.update([srt,fin],time,zxccurve);
}

zxcBAnimatorOOP.prototype.update=function(srtfin,time,zxccurve){
 this.curve=(typeof(zxccurve)=='string')?zxccurve.charAt(0).toLowerCase():(this.curve)?this.curve:'x';
 this.inc=Math.PI/(2*time);
 this.time=time||this.time||2000;
 this.data=[srtfin[0],srtfin[0],srtfin[1]];
 this.srttime=new Date().getTime();
 this.cng();
}

zxcBAnimatorOOP.prototype.cng=function(){
 var ms=new Date().getTime()-this.srttime;
 this.data[0]=(this.curve=='s')?Math.floor((this.data[2]-this.data[1])*Math.sin(this.inc*ms)+this.data[1]):(this.curve=='c')?(this.data[2])-Math.floor((this.data[2]-this.data[1])*Math.cos(this.inc*ms)):(this.data[2]-this.data[1])/this.time*ms+this.data[1];
 if (this.mde!='left'&&this.mde!='top'&&this.data[0]<0) this.data[0]=0;
 if (this.mde!='opacity') this.obj.style[this.mde]=this.data[0]+'px';
 else  zxcOpacity(this.obj,this.data[0]);
 if (ms<this.time) this.to=setTimeout(function(oop){return function(){oop.cng();}}(this),10);
 else {
  this.data[0]=this.data[2];
  if (this.mde!='opacity') this.obj.style[this.mde]=this.data[0]+'px';
  else zxcOpacity(this.obj,this.data[0]);
 }
}

function zxcOpacity(obj,opc){
 if (opc<0||opc>100) return;
 obj.style.filter='alpha(opacity='+opc+')';
 obj.style.opacity=obj.style.MozOpacity=obj.style.KhtmlOpacity=opc/100-.001;
}


function zxcSlide(mde,id,nu,spd,ud){
 var mde=mde=='V'?['top','Top']:['left','Left'];
 var par=document.getElementById(id);
 var slide=par.getElementsByTagName('DIV')[0];
 if (!slide.inc){
  var imgs=slide.getElementsByTagName('IMG');
  slide.inc=imgs[nu]['offset'+mde[1]]-SVInt(imgs[nu],'margin-'+mde[1])
  slide.pos=0;
  slide.min=imgs[imgs.length-nu]['offset'+mde[1]]-SVInt(imgs[nu],'margin-'+mde[1]);
 }
 slide.pos=Math.min(Math.max(slide.pos+=slide.inc*ud,-slide.min),0);
 zxcBAnimator(mde[0],slide,SVInt(slide,mde[0]),slide.pos,spd);

}
function SVInt(obj,par){
 if (obj.currentStyle) return parseInt(obj.currentStyle[par.replace(/-/g,'')]);
 return parseInt(document.defaultView.getComputedStyle(obj,null).getPropertyValue(par.toLowerCase()));
}