@interface HKHorizontalFlowLayout : UICollectionViewFlowLayout @property (nonatomic) BOOL snapsToItemBoundaries; @property (nonatomic) BOOL snapsToItemCenters; @property (nonatomic) double leadingInset; @property (nonatomic) double trailingInset; + (double)snapToBoundariesDecelerationRate; - (id)init; - (struct CGPoint { double x0; double x1; })targetContentOffsetForProposedContentOffset:(struct CGPoint { double x0; double x1; })a0 withScrollingVelocity:(struct CGPoint { double x0; double x1; })a1; @end