ios – Calculating sizeForItemAt for UICollectionViewDelegateFlowLayout

I have been messing round with NASA’s Astronomical Image of the Day API and am making an attempt to point out the pictures in a group view with three gadgets per row. As anticipated, I am utilizing UICollectionViewDelegateFlowLayout. To outline the scale of every picture, I am utilizing the sizeForItemAt technique. Excessive degree, I am taking the width of the gathering view, subtracting the padding outlined in different delegate strategies, and dividing that remaining house by the specified variety of columns (3). Surprisingly, it appears my calculations are simply barely off as a result of I solely get 2 columns with a fairly hefty house within the center (and it is not simply that some hypothetical photographs within the center have not completed loading!).

Anybody have any concept what’s going on right here? This is my code:

    extension ApodCollectionViewController: UICollectionViewDelegateFlowLayout {
       fileprivate enum Constants {
           static let numColumns = 3.0
           static let spacing = 10.0
       }

       /// This offers measurement of every merchandise.
       func collectionView(_ collectionView: UICollectionView, format collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
           let availableWidth = collectionView.bounds.width - ((Constants.numColumns+1)*Constants.spacing)
           let widthPer = availableWidth/Constants.numColumns
           return CGSize(width: widthPer, top: widthPer)
       }

       /// This offers inset round total assortment view.
       func collectionView(_ collectionView: UICollectionView, format collectionViewLayout: UICollectionViewLayout, insetForSectionAt part: Int) -> UIEdgeInsets {
           return UIEdgeInsets(prime: Constants.spacing, left: Constants.spacing, backside: Constants.spacing, proper: Constants.spacing)
       }

       /// This offers house between gadgets (horizontal).
       func collectionView(_ collectionView: UICollectionView, format collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt part: Int) -> CGFloat {
           return Constants.spacing
       }

       /// This offers house between rows (vertical).
       func collectionView(_ collectionView: UICollectionView, format collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt part: Int) -> CGFloat {
           return Constants.spacing
       }
   }

I printed off the collectionView’s bounds’ width to be sure that wasn’t surprising. It’s in reality 402, which is the anticipated variety of factors defining the width of an iPhone 16 Professional display.

Anybody have any concepts? Thanks!