How would one write this in Swift?
Update: posted the method I'm trying to convert, originally posted a different method that was not what I was trying to covert
This works in Objective C, but not Swift. I get conversion errors when I try to use ceilf
and floorf
with CGFloat
.
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset
{
float pageWidth = 200 + 30; // width + space
float currentOffset = scrollView.contentOffset.x;
float targetOffset = targetContentOffset->x;
float newTargetOffset = 0;
if (targetOffset > currentOffset)
newTargetOffset = ceilf(currentOffset / pageWidth) * pageWidth;
else
newTargetOffset = floorf(currentOffset / pageWidth) * pageWidth;
if (newTargetOffset < 0)
newTargetOffset = 0;
else if (newTargetOffset > scrollView.contentSize.width)
newTargetOffset = scrollView.contentSize.width;
targetContentOffset->x = currentOffset;
[scrollView setContentOffset:CGPointMake(newTargetOffset, 0) animated:YES];
}
To answer from Christian: I was able to rewrite this in Swift. I set everything up as Float
to do the math then converted to CGFloat
as Christian mentioned was possible. His answer is technically correct, but showing a newer iOS developer how this is written in Swift was what I was looking for.
func scrollViewWillEndDragging(scrollView: UIScrollView!, withVelocity velocity: CGPoint, targetContentOffset: UnsafePointer<CGPoint>) {
var pageWidth = Float(200 + 30)
var currentOffset = Float(scrollView.contentOffset.x)
var targetOffset = Float(targetContentOffset.memory.x)
var newTargetOffset = Float(0)
var scrollViewWidth = Float(scrollView.contentSize.width)
if targetOffset > currentOffset {
newTargetOffset = ceilf(currentOffset / pageWidth) * pageWidth
} else {
newTargetOffset = floorf(currentOffset / pageWidth) * pageWidth
}
if newTargetOffset < 0 {
newTargetOffset = 0
} else if newTargetOffset > currentOffset {
newTargetOffset = currentOffset
}
Float(targetContentOffset.memory.x) == currentOffset
scrollView.setContentOffset(CGPointMake(CGFloat(newTargetOffset), 0), animated: true)
}