Setter for ContentOffset in DVParallaxView

DVParallaxViewContentOffset.m

-(void)setContentOffset:(CGPoint)contentOffset {
    BOOL backgroundReachedEdgeX = NO;
    BOOL backgroundReachedEdgeY = NO;
    double contentDivider;

    //1
    if (self.backgroundImageView) {
        contentDivider = self.subviews.count*self.parallaxDistanceFactor;
        CGPoint newCenter = CGPointMake(self.backgroundImageView.center.x + (contentOffset.x - _contentOffset.x)/contentDivider,
                                        self.backgroundImageView.center.y - (contentOffset.y - _contentOffset.y)/contentDivider);
        
        if ((newCenter.x - self.backgroundImageView.frame.size.width/2.f) > 0.f ||
            (newCenter.x + self.backgroundImageView.frame.size.width/2.f) < self.bounds.size.width) {
            newCenter.x = self.backgroundImageView.center.x;
            backgroundReachedEdgeX = YES;
        }
        
        if ((newCenter.y - self.backgroundImageView.frame.size.height/2.f) > 0.f ||
            (newCenter.y + self.backgroundImageView.frame.size.height/2.f) < self.bounds.size.height) {
            newCenter.y = self.backgroundImageView.center.y;
            backgroundReachedEdgeY = YES;
        }
        
        self.backgroundImageView.center = newCenter;
    }
    //
  
    //2
    for (int i = 1; i<self.subviews.count; ++i) {
        UIView *view = [self.subviews objectAtIndex:i];
        contentDivider = (view == self.frontView)?-self.parallaxFrontFactor:((self.subviews.count - i)*self.parallaxDistanceFactor);
        CGFloat newCenterX = backgroundReachedEdgeX?view.center.x:(view.center.x + (contentOffset.x - _contentOffset.x)/contentDivider);
        CGFloat newCenterY = backgroundReachedEdgeY?view.center.y:(view.center.y - (contentOffset.y - _contentOffset.y)/contentDivider);
        view.center = CGPointMake(newCenterX, newCenterY);
    }
    //
    
    _contentOffset = contentOffset;
}