启动图左滑又滑动画

@property int currentIndex;

@property (nonatomic) CGFloat beginOffset;

@property (nonatomic) NSInteger currentPage;

#define finalAngel 30.0f

#define perspective 1.0/-600

#define finalAlpha 0.6f

#define zoom  0.88

#define finalAlpha 0.6f

- (void)scrollViewDidScroll:(UIScrollView *)scrollView

{

CGFloat pageWidth = scrollView.frame.size.width;

CGFloat offset = scrollView.contentOffset.x;

CGFloat percent = MIN(1,fabs((offset - self.beginOffset)/pageWidth));

UIImageView *sourceView =  scrollView.subviews[self.currentIndex];

UIImageView *destView  = nil;

int nextIndex = (offset - self.beginOffset)>0? self.currentIndex+1 :self.currentIndex-1;

if(nextIndex>=0 && nextIndex<3){

destView = scrollView.subviews[nextIndex];

}

if(offset - self.beginOffset>0) {

}

CGFloat sourceViewZoom =1-(1-zoom)*percent;

sourceView.transform=CGAffineTransformMakeScale(sourceViewZoom, sourceViewZoom);

sourceView.alpha =  1 - percent*(1-finalAlpha);

if(destView){

CGFloat destViewZoom = zoom+(1-zoom)*percent;

destView.transform=CGAffineTransformMakeScale(destViewZoom, destViewZoom);

destView.alpha = finalAlpha + (1-finalAlpha)*percent;

}

NSLog(@"---------------%f--------------%d",offset,_currentIndex);

CATransform3D transform = CATransform3DIdentity;

transform.m34 = perspective;

CGFloat angle =  finalAngel * M_PI / 180.0f*percent;

if(offset - self.beginOffset<0){

angle = -angle;

}

transform = CATransform3DRotate(transform, angle , 0.0f, 1.0f, 0.0f);

sourceView.layer.transform = transform;

sourceView.alpha =  1 - percent*(1-finalAlpha);

if(destView){

CATransform3D transform = CATransform3DIdentity;

transform.m34 = perspective;

CGFloat angle =  - finalAngel * M_PI / 180.0f * (1-percent);

if(offset - self.beginOffset<0){

angle = -angle;

}

transform = CATransform3DRotate(transform, angle , 0.0f, 1.0f, 0.0f);

destView.layer.transform = transform;

destView.alpha = finalAlpha + (1-finalAlpha)*percent;

}

}

-(void) scrollViewWillBeginDragging:(UIScrollView *)scrollView

{

self.beginOffset = scrollView.contentOffset.x;

CGFloat pageWidth = scrollView.frame.size.width;

CGFloat offset = scrollView.contentOffset.x;

self.currentIndex = floor((offset - pageWidth /3) / pageWidth) + 1;

}