1  inline	CAAnimation*
   2  BounceAnimationElement( CGPoint pFrom, CGPoint pTo, double pBeginTime, double pDuration, CAMediaTimingFunction* pMTF )
   3  {	CABasicAnimation* v = [ CABasicAnimation animationWithKeyPath:@"position" ];
   4  	v.fromValue = [ NSValue valueWithCGPoint:pFrom ];
   5  	v.toValue = [ NSValue valueWithCGPoint:pTo ];
   6  	v.beginTime = pBeginTime;
   7  	v.duration  = pDuration;
   8  	v.timingFunction = pMTF;
   9  	return v;
  10  }
  11  
  12  inline	CAAnimation*
  13  BounceAnimation( CALayer* pL, CGPoint pDest, double pInitialDuration = 1, double pK = .3, size_t pRepeat = 10 )
  14  {	CAMediaTimingFunction* wMTF_D = [ CAMediaTimingFunction functionWithControlPoints:1./3. :0 :2./3. :1./3. ];
  15  	CAMediaTimingFunction* wMTF_U = [ CAMediaTimingFunction functionWithControlPoints:1./3. :2./3. :2./3. :1 ];
  16  
  17  	CGPoint wOrigin = pL.position;
  18  
  19  	NSMutableArray* wAnimationArray = NSMutableArray.array;
  20  	[ wAnimationArray addObject:BounceAnimationElement( pL.position, pDest, 0, pInitialDuration, wMTF_D ) ];
  21  
  22  	double	wBeginTime = pInitialDuration;
  23  
  24  	double	wK = 1;
  25  	while ( pRepeat-- )
  26  	{	wK *= pK;
  27  		CGPoint wPoint = CGPointMake
  28  		(	wOrigin.x * wK + pDest.x * ( 1 - wK )
  29  		,	wOrigin.y * wK + pDest.y * ( 1 - wK )
  30  		);
  31  		double wDuration = pInitialDuration * wK * ( 1 / sqrt( wK ) );
  32  		[ wAnimationArray addObject:BounceAnimationElement( pDest, wPoint, wBeginTime, wDuration, wMTF_U ) ];
  33  		wBeginTime += wDuration;
  34  		[ wAnimationArray addObject:BounceAnimationElement( wPoint, pDest, wBeginTime, wDuration, wMTF_D ) ];
  35  		wBeginTime += wDuration;
  36  	}
  37  
  38  	pL.position = pDest;
  39  
  40  	CAAnimationGroup* v = CAAnimationGroup.animation;
  41  	v.duration = wBeginTime;
  42  	v.animations = wAnimationArray;
  43  
  44  	return v;
  45  }
  46  
  47  -	(IBAction)
  48  Group
  49  {	[ mL addAnimation:BounceAnimation( mL, CGPointMake( 160, 240 ) ) forKey:nil ];
  50  }
  51