Scroll a background in a different speed on a UIScrollView

Question

When somebody does a wipe gesture to scroll the content from left to right, I would like to have a background image scrolling into the same direction, but at a different spe

Answer 1

For example you have multiple scrollviews, want them scroll difference speed. here is the modification code base on Salamatizm answer:

CGSize screenSize = [[UIScreen mainScreen] bounds].size;
  float factor = scrollView.contentOffset.x / (scrollView.contentSize.width - screenSize.width);
  if (factor < 0) factor = 0;
  if (factor > 1) factor = 1;

  CGSize parralaxSize = self.parralaxBackgroundView.contentSize;
  CGPoint parallaxOffset = CGPointMake(-(factor * (screenSize.width - parralaxSize.width)), 0);
  [self.parralaxBackgroundView setContentOffset:parallaxOffset animated:NO];