function PlayAlpha(ObjectName) //Filter对象名ID值
{
    this.pName=new Array("s","x","y","fx","fy","o","fo");
    this.SrcName=new Array("style","startx","starty","finishx","finishy","opacity","finishopacity");
    this.Object=ObjectName;     this.MaxStep=0;
    this.Speed=5;    this.x=0;this.y=0;
    this.fx=0;this.fy=0;
    this.o=100; this.fo=100;
    this.ex=0; this.ey=0;
    this.efx=0; this.efy=0;
    this.eo=0; this.efo=0;
    this.Cmd=new Array();
    this.CmdCount=0;
    this.CurNo=0;    this.Step=0; this.MaxStep=0;
    this.Status=0; // 0 保留 1 正在播放 -1 中断,或者播放完成 -2 分析命令出错
    this.Error=""; //当前的错误信息串
    this.Init=PlayAlpha_Init;
    this.SetSpeed=PlayAlpha_SetSpeed;
    this.SetValue=PlayAlpha_SetValue;
    this.GetValue=PlayAlpha_GetValue;
    this.GetName=PlayAlpha_GetName;
    this.Play=PlayAlpha_Play;
    this.Stop=PlayAlpha_Stop;
    this.SetInitValue=PlayAlpha_SetInitValue;
    this.Analyze=PlayAlpha_Analyze;
    return(this);
}

function PlayAlpha_GetName(s)
{
    s=s.toLowerCase(); 
    for(i=0;i<this.pName.length;i++)
    if(s==this.pName[i]) return(this.SrcName[i]);
    return(""); 
}

function PlayAlpha_GetValue(name)
{ //取得对象的相关属性值
    name=this.GetName(name);
    if(name!="")
        return(eval(this.Object+'.filters.item("Alpha").'+name))
    else
        return(""); 
}


function PlayAlpha_SetValue(name,value)
{ //设置对象的相关属性
    name=this.GetName(name);
    if(name!="" && !isNaN(value))
    { value=parseInt(value,10);
     if(value>=0 && value<=100 && name!="style" || name=="style" && value<=3 && value>=0) 
     eval(this.Object+'.filters.item("Alpha").'+name+'='+value);
    } 
}


function PlayAlpha_SetSpeed(n)
{ //设置对象的播放速度
    if(n>=0 && n<=1000) this.Speed=n;
}

function PlayAlpha_Stop() //停止播放
{
   if(this.Status==1) this.Status=-1;
}

function PlayAlpha_Init()
{ //对象初始化
    var m;
    this.x=this.GetValue("x");     this.y=this.GetValue("y");
    this.fx=this.GetValue("fx");   this.fy=this.GetValue("fy");
    this.o=this.GetValue("o");    this.fo=this.GetValue("fo");
    this.s=this.GetValue("s");     this.ex=this.x;
    this.ey=this.y;    this.efx=this.fx;
    this.efy=this.fy;    this.eo=this.o;
    this.efo=this.fo;
    if(this.CmdCount>1 && this.CurCmdNo<=this.CmdCount && this.CurCmdNo>=1)
    { this.SetInitValue(this.Cmd[this.CurCmdNo-1],true);
        this.SetInitValue(this.Cmd[this.CurCmdNo],false);
        this.Step=0;
        //以下计算转换的最大步长
        m=Math.abs(this.o-this.eo);
        m=Math.max(m,Math.abs(this.x-this.ex)); 
        m=Math.max(m,Math.abs(this.y-this.ey)); 
        m=Math.max(m,Math.abs(this.fo-this.efo)); 
        m=Math.max(m,Math.abs(this.fx-this.efx)); 
        m=Math.max(m,Math.abs(this.fy-this.efy)); 
        this.MaxStep=m;
    } 
else 
    this.MaxStep=0;
}

function PlayAlpha_Play(s) //需要Play的命令串,返回是否有错
{   var m1 ,m2;
    if(this.Status==1) //当前有对象正在播放,返回
    { this.Error="正在播放中,不能接收另一种播放方式！,";return(true);}

    this.Cmd=s.split(";"); this.CmdCount=this.Cmd.length;
    if(this.CmdCount>1) //需要设置两个或两个变换以下才能Play
    { this.Status=0;
        for(i=0;i<this.CmdCount && this.Status!=0;i++)
        { this.Analyze(this.Cmd[i]); //分析命令串
           if(this.Status!=0)//没能过,则返回
            {this.CmdCount=0;this.CurCmdNo=0;
              return(true); 
            } 
        }
    //通过,则开始Play
    this.CurCmdNo=1;//当前播放的是第一个转换
    this.Status=1 ;//正在播放
    this.Init(); this.Error="正在播放"; StartPlay();
    return(false)
    } 
else 
    { this.Status=-2; this.Error="没有可播放的命令串！"; return(true); } 
}

function PlayAlpha_Analyze(s) //分析命令串是否合法
{
    s=s.toLowerCase();
    var nvl=s.split(",");
    for(var j=0;j<nvl.length;j++)
    {if(nvl[j]!="")
        { var nv=nvl[i].split("=");
          if(nv.length==2 && !isNaN(nv[1]))
            {  n=parseInt(nv[1]);
               if(n<0 || n>100 || nv[0]=="style" && n>3)
                { this.Status=-2;
                  this.Error="设置的值必须在0-100之间,并且s取值为0-100之间";
                  return(false); 
                }
              if(this.GetName(nv[0])=="") //是否有该属性
                { this.Status=-2;
                  this.Error="不能识别的属性："+nv[0];
                   return(false);
                }
            }
        else
            { this.Status=-2;
              this.Error="命令格式必需为\"属性名[s,x,y,fx,fy,o,fo]=属性值[0-100,0-3]\"";
              return(false);
            } 
    }
   else
    { this.Status=-2; this.Error="命令串不能为空值!"; return(false); }
} 

if(nvl.length>0)
    {this.Status=0; return(true); }
else
    {this.Status=-2; this.Error="命令串不能为空值!"; return(false); }

}


function PlayAlpha_SetInitValue(s,isInit)
{
  var n,nvl=s.split(",");
  for(var j=0;j<nvl.length;j++)
  { nv=nvl[j].split("="); n=parseInt(nv[1]);
    switch(nv[0])
    {case "x":if(isInit) {this.x=n;this.SetValue("x",n);} this.ex=n; break;
     case "y":if(isInit) {this.y=n;this.SetValue("y",n);} this.ey=n; break;
     case "o":if(isInit) {this.o=n;this.SetValue("o",n);} this.eo=n; break;
     case "fx":if(isInit) {this.fx=n;this.SetValue("fx",n);} this.efx=n; break;
     case "fo":if(isInit) {this.fo=n;this.SetValue("fo",n);} this.efo=n; break;
     case "fy":if(isInit) {this.fy=n;this.SetValue("fy",n);} this.efy=n; break; 
     case "s": if(isInit) this.SetValue("s",n);break;
   }
  }
}

function StartPlay()
{
var c=0,t;
if(Obj.Status==-1) //中断则退出
    return;
if(Obj.Step>Obj.MaxStep) //当前的命令串Play完成
{   Obj.CurCmdNo++;
    if(Obj.CurCmdNo>=Obj.CmdCount) //已播放完成
    { Obj.Status=-1; Obj.Error="播放完成"; return; }
      Obj.Init();//对象初如化;
    }
t=(Obj.Step/Obj.MaxStep);
c=(Obj.ex-Obj.x)*t+Obj.x+0.5;Obj.SetValue("x",c);
c=(Obj.ey-Obj.y)*t+Obj.y+0.5;Obj.SetValue("y",c);
c=(Obj.eo-Obj.o)*t+Obj.o+0.5; Obj.SetValue("o",c);
c=(Obj.efo-Obj.fo)*t+Obj.fo+0.5; Obj.SetValue("fo",c);
c=(Obj.efx-Obj.fx)*t+Obj.fx+0.5; Obj.SetValue("fx",c);
c=(Obj.efy-Obj.fy)*t+Obj.fy+0.5;Obj.SetValue("fy",c);
Obj.Step=Obj.Step+1;
window.setTimeout("StartPlay()",Obj.Speed); //继续进行下一步的播放
}