Silverlight制作逐帧动画 v2 - part2

         private   string [] shippics  =   new   string [] {  " Ship1/1.png " ,  " Ship1/2.png " ,  " Ship1/3.png " ,  " Ship1/4.png "  };
         protected  DateTime lastTick;
         protected  TimeSpan elapsed;


         private   double  lasrFrameTime  =   0 ;
         private   int  currentFrame  =   0 ;

         private   double  fps  =   15 ;

         public  MainPage()
        {
            InitializeComponent();
            lastTick  =  DateTime.Now;
            CompositionTarget.Rendering  +=   new  EventHandler(CompositionTarget_Rendering);
        }

         void  CompositionTarget_Rendering( object  sender, EventArgs e)
        {
            DateTime now  =  DateTime.Now;
            elapsed  =  now  -  lastTick;
            lastTick  =  DateTime.Now;

            lasrFrameTime  +=  elapsed.TotalSeconds;


             if  (lasrFrameTime  > (  1   /  fps))
            {
                lasrFrameTime  =   0 ;

                currentFrame ++ ;
                currentFrame  %=  shippics.Length;
                RenderShip();
            }
        }

         private   void  RenderShip()
        {
            var imageBrush  =   new  ImageBrush();
            imageBrush.Stretch  =  Stretch.None;
            imageBrush.AlignmentX  =  AlignmentX.Left;
            imageBrush.AlignmentY  =  AlignmentY.Top;
            imageBrush.ImageSource  =   new  BitmapImage( new  Uri( " /slShipAnimate;component/ "   +  shippics[currentFrame], UriKind.Relative));
            myShip.Fill  =  imageBrush;
        }