AdaptivePagingScrollViewStep01.swift

struct AdaptivePagingScrollView: View {
    
    private let items: [AnyView]
    private let itemPadding: CGFloat
    private let itemSpacing: CGFloat
    private let itemWidth: CGFloat
    private let itemsAmount: Int
    private let contentWidth: CGFloat
    
    private let leadingOffset: CGFloat
    private let scrollDampingFactor: CGFloat = 0.66
    
    @Binding var currentPageIndex: Int
    
    @State private var currentScrollOffset: CGFloat = 0
    @State private var gestureDragOffset: CGFloat = 0
    
    init<A: View>(currentPageIndex: Binding<Int>,
                  itemsAmount: Int,
                  itemWidth: CGFloat,
                  itemPadding: CGFloat,
                  pageWidth: CGFloat,
                  @ViewBuilder content: () -> A) {

        let views = content()
        self.items = [AnyView(views)]

        self._currentPageIndex = currentPageIndex

        self.itemsAmount = itemsAmount
        self.itemSpacing = itemPadding
        self.itemWidth = itemWidth
        self.itemPadding = itemPadding
        self.contentWidth = (itemWidth+itemPadding)*CGFloat(itemsAmount)

        let itemRemain = (pageWidth-itemWidth-2*itemPadding)/2
        self.leadingOffset = itemRemain + itemPadding
    }
    
    /// {  * * *  Functions  * * * }
    
    /// {  * * *  Body  * * * }
}