492 lines
19 KiB
Swift
492 lines
19 KiB
Swift
//
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// Carousel.swift
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// VDS
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//
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// Created by Kanamarlapudi, Vasavi on 29/05/24.
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//
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import Foundation
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import UIKit
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import VDSCoreTokens
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import Combine
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/// A carousel is a collection of related content in a row that a customer can navigate through horizontally.
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/// Use this component to show content that is supplementary, not essential for task completion.
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@objc(VDSCarousel)
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open class Carousel: View {
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//--------------------------------------------------
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// MARK: - Initializers
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//--------------------------------------------------
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required public init() {
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super.init(frame: .zero)
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}
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public override init(frame: CGRect) {
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super.init(frame: .zero)
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}
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public required init?(coder: NSCoder) {
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super.init(coder: coder)
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}
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//--------------------------------------------------
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// MARK: - Enums
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//--------------------------------------------------
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/// Space between each tile. The default value will be 24px (6X) in tablet and 12px (3X) in mobile.
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public enum Gutter: String, CaseIterable {
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case twelvePX = "12px"
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case twentyFourPX = "24px"
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var value: CGFloat {
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switch self {
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case .twelvePX:
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VDSLayout.space3X
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case .twentyFourPX:
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VDSLayout.space6X
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}
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}
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}
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/// Enum used to describe the pagination display for this component.
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public enum PaginationDisplay: String, CaseIterable {
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case persistent, none
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}
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/// Enum used to describe the peek for this component.
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/// This is how much a tile is partially visible. It is measured by the distance between the edge of the tile and the edge of the viewport or carousel container. A peek can appear on the left and/or right edge of the carousel container or viewport, depending on the carousel’s scroll position.
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public enum Peek: String, CaseIterable {
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case standard, minimum, none
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}
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/// Enum used to describe the vertical of slotAlignment.
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public enum Vertical: String, CaseIterable {
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case top, middle, bottom
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}
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/// Enum used to describe the horizontal of slotAlignment.
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public enum Horizontal: String, CaseIterable {
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case left, center, right
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}
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/// Enum used to describe the width of a fixed value or percentage of parent's width.
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public enum Width {
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case percentage(CGFloat)
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case value(CGFloat)
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}
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//--------------------------------------------------
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// MARK: - Public Properties
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//--------------------------------------------------
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/// Aspect-ratio options for tilelet in the carousel. If 'none' is passed, the tilelet will take the height of the tallest item in the carousel.
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open var aspectRatio: Tilelet.AspectRatio = .ratio1x1 { didSet { setNeedsUpdate() } }
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/// Data used to render tilelets in the carousel.
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open var data: [Any] = [] { didSet { setNeedsUpdate() } }
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/// If provided, width of slots will be rendered based on this value. If omitted, default widths are rendered.
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open var width : Width? {
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get { _width }
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set {
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if let newValue {
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switch newValue {
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case .percentage(let percentage):
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if percentage >= 10 && percentage <= 100.0 {
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_width = newValue
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}
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case .value(let value):
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if value > minimumSlotWidth { /*(size.minimumSlotWidth)*/
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_width = newValue
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}
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}
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} else {
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_width = nil
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}
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setNeedsUpdate()
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}
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}
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/// Space between each tile. The default value will be 24px (6X) in tablet and 12px (3X) in mobile.
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open var gutter: Gutter {
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get { return _gutter }
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set {
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_gutter = newValue
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setNeedsUpdate()
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}
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}
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/// The amount of slides visible in the carousel container at one time. The default value will be 3UP in tablet and 1UP in mobile.
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open var layout: CarouselScrollbar.Layout {
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get { return _layout }
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set {
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_layout = newValue
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setNeedsUpdate()
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}
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}
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/// A callback when moving the carousel. Returns event object and selectedGroupIndex.
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open var onChange: ((Int) -> Void)? {
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get { nil }
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set {
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onChangeCancellable?.cancel()
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if let newValue {
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onChangeCancellable = onChangePublisher
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.sink { c in
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newValue(c)
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}
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}
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}
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}
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/// Config object for pagination.
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open var pagination: CarouselPaginationModel {
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get { return _pagination }
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set {
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_pagination = newValue
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setNeedsUpdate()
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}
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}
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/// If provided, will determine the conditions to render the pagination arrows.
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open var paginationDisplay: PaginationDisplay {
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get { return _paginationDisplay }
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set {
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_paginationDisplay = newValue
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setNeedsUpdate()
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}
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}
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/// If provided, will apply margin to pagination arrows. Can be set to either positive or negative values.
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/// The default value will be 12px in tablet and 8px in mobile. These values are the default in order to avoid overlapping content within the carousel.
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open var paginationInset: CGFloat {
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get { return _paginationInset }
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set {
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_paginationInset = newValue
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updatePaginationInset()
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}
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}
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/// Options for user to configure the partially-visible tile in group. Setting peek to 'none' will display arrow navigation icons on mobile devices.
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open var peek: Peek {
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get { return _peek }
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set {
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_peek = newValue
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setNeedsUpdate()
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}
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}
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/// The initial visible slide's index in the carousel.
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open var selectedIndex: Int? { didSet { setNeedsUpdate() } }
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/// If provided, will set the alignment for slot content when the slots has different heights.
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open var slotAlignment: [CarouselSlotAlignmentModel] = [] { didSet { setNeedsUpdate() } }
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//--------------------------------------------------
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// MARK: - Private Properties
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//--------------------------------------------------
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// Sizes are from InVision design specs.
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internal var containerSize: CGSize { CGSize(width: 320, height: 44) }
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private let contentStackView = UIStackView().with {
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$0.translatesAutoresizingMaskIntoConstraints = false
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$0.axis = .vertical
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$0.distribution = .fill
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$0.spacing = UIDevice.isIPad ? VDSLayout.space3X : VDSLayout.space1X
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$0.backgroundColor = .clear
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}
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internal var carouselScrollBar = CarouselScrollbar().with {
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$0.layout = UIDevice.isIPad ? .threeUP : .oneUP
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$0.position = 0
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$0.backgroundColor = .clear
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}
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internal var containerView = View().with {
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$0.clipsToBounds = true
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$0.backgroundColor = .clear
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}
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internal var scrollContainerView = View().with {
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$0.clipsToBounds = true
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$0.backgroundColor = .clear
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}
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private var scrollView = UIScrollView().with {
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$0.translatesAutoresizingMaskIntoConstraints = false
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$0.backgroundColor = .clear
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}
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/// Previous button to show previous slide.
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private var previousButton = ButtonIcon().with {
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$0.kind = .lowContrast
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$0.iconName = .leftCaret
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$0.iconOffset = .init(x: -2, y: 0)
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$0.customContainerSize = UIDevice.isIPad ? 40 : 28
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$0.icon.customSize = UIDevice.isIPad ? 16 : 12
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}
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/// Next button to show next slide.
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private var nextButton = ButtonIcon().with {
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$0.kind = .lowContrast
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$0.iconName = .rightCaret
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$0.iconOffset = .init(x: 2, y: 0)
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$0.customContainerSize = UIDevice.isIPad ? 40 : 28
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$0.icon.customSize = UIDevice.isIPad ? 16 : 12
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}
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/// A publisher for when the scrubber position changes. Passes parameters (position).
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open var onChangePublisher = PassthroughSubject<Int, Never>()
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private var onChangeCancellable: AnyCancellable?
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/// A publisher for when the carousel moves. Passes parameters (data).
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open var onScrollPublisher = PassthroughSubject<Array<Any>, Never>()
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private var onScrollCancellable: AnyCancellable?
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internal var _layout: CarouselScrollbar.Layout = UIDevice.isIPad ? .threeUP : .oneUP
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internal var _pagination: CarouselPaginationModel = .init(kind: .lowContrast, floating: true)
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internal var _paginationDisplay: PaginationDisplay = .none
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internal var _paginationInset: CGFloat = UIDevice.isIPad ? VDSLayout.space3X : VDSLayout.space2X
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internal var _gutter: Gutter = UIDevice.isIPad ? .twentyFourPX : .twelvePX
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internal var _peek: Peek = .none
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internal var _numberOfSlides: Int = 1
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private var _width: Width? = nil
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private var selectedGroupIndex: Int? { didSet { setNeedsUpdate() } }
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private var containerStackHeightConstraint: NSLayoutConstraint?
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private var containerViewHeightConstraint: NSLayoutConstraint?
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private var prevButtonLeadingConstraint: NSLayoutConstraint?
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private var nextButtonTrailingConstraint: NSLayoutConstraint?
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// The scrollbar has top 5X space. So the expected top space is adjusted for tablet and mobile.
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let scrollbarTopSpace = UIDevice.isIPad ? VDSLayout.space3X : VDSLayout.space1X
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var slotHeight = 100.0
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var peekMinimum = 24.0
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var minimumSlotWidth = 0.0
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//--------------------------------------------------
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// MARK: - Lifecycle
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//--------------------------------------------------
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open override func initialSetup() {
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super.initialSetup()
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}
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open override func setup() {
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super.setup()
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isAccessibilityElement = false
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// add containerView
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addSubview(containerView)
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containerView
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.pinTop()
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.pinBottom()
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.pinLeading()
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.pinTrailing()
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.heightGreaterThanEqualTo(containerSize.height)
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containerView.centerXAnchor.constraint(equalTo: centerXAnchor).activate()
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// add content stackview
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containerView.addSubview(contentStackView)
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// add scrollview
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scrollContainerView.addSubview(scrollView)
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scrollView.pinToSuperView()
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// add pagination button icons
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scrollContainerView.addSubview(previousButton)
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previousButton
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.pinLeadingGreaterThanOrEqualTo()
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.pinCenterY()
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scrollContainerView.addSubview(nextButton)
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nextButton
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.pinTrailingLessThanOrEqualTo()
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.pinCenterY()
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// add scroll container view & carousel scrollbar
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contentStackView.addArrangedSubview(scrollContainerView)
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contentStackView.addArrangedSubview(carouselScrollBar)
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contentStackView.setCustomSpacing(scrollbarTopSpace, after: scrollContainerView)
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contentStackView
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.pinTop()
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.pinBottom()
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.pinLeading()
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.pinTrailing()
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.heightGreaterThanEqualTo(containerSize.height)
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contentStackView.centerXAnchor.constraint(equalTo: centerXAnchor).activate()
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addlisteners()
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}
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open override func updateView() {
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super.updateView()
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carouselScrollBar.numberOfSlides = data.count
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carouselScrollBar.layout = _layout
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carouselScrollBar.position = (carouselScrollBar.position == 0 || carouselScrollBar.position > carouselScrollBar.numberOfSlides) ? 1 : carouselScrollBar.position
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carouselScrollBar.isHidden = (totalPositions() <= 1) ? true : false
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// When peek is set to ‘none,’ pagination controls are automatically set to persistent.
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if peek == .none {
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paginationDisplay = .persistent
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}
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containerViewHeightConstraint?.isActive = false
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containerStackHeightConstraint?.isActive = false
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updatePaginationControls()
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getSlotWidth()
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// perform a loop to iterate each subView
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scrollView.subviews.forEach { subView in
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// removing subView from its parent view
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subView.removeFromSuperview()
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}
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// add carousel items
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if data.count > 0 {
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var xPos = 0.0
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for x in 0...data.count - 1 {
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let carouselSlot = View().with {
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$0.clipsToBounds = true
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$0.backgroundColor = UIColor(red: CGFloat(216) / 255.0, green: CGFloat(218) / 255.0, blue: CGFloat(218) / 255.0, alpha: 1)
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}
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scrollView.addSubview(carouselSlot)
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carouselSlot
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.pinTop()
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.pinBottom()
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.pinLeading(xPos)
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.width(minimumSlotWidth)
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.height(slotHeight)
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carouselSlot.layer.cornerRadius = 12.0
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xPos = xPos + minimumSlotWidth + gutter.value
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}
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scrollView.contentSize = CGSize(width: xPos - gutter.value, height: slotHeight)
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}
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let containerHeight = slotHeight + scrollbarTopSpace + containerSize.height
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if carouselScrollBar.isHidden {
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containerStackHeightConstraint = contentStackView.heightAnchor.constraint(equalToConstant: slotHeight)
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containerViewHeightConstraint = containerView.heightAnchor.constraint(equalToConstant: slotHeight)
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} else {
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containerStackHeightConstraint = contentStackView.heightAnchor.constraint(equalToConstant: containerHeight)
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containerViewHeightConstraint = containerView.heightAnchor.constraint(equalToConstant: containerHeight)
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}
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containerViewHeightConstraint?.isActive = true
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containerStackHeightConstraint?.isActive = true
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layoutIfNeeded()
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}
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open override func reset() {
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for subview in subviews {
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for recognizer in subview.gestureRecognizers ?? [] {
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subview.removeGestureRecognizer(recognizer)
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}
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}
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super.reset()
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}
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//--------------------------------------------------
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// MARK: - Private Methods
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//--------------------------------------------------
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func addlisteners() {
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nextButton.onClick = { _ in self.nextButtonClick() }
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previousButton.onClick = { _ in self.previousButtonClick() }
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/// will be called when the thumb move forward.
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carouselScrollBar.onMoveForward = { [weak self] scrubberId in
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guard let self else { return }
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updateScrollPosition(position: scrubberId, callbackText:"onMoveForward")
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}
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/// will be called when the thumb move backward.
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carouselScrollBar.onMoveBackward = { [weak self] scrubberId in
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guard let self else { return }
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updateScrollPosition(position: scrubberId, callbackText:"onMoveBackward")
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}
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/// will be called when the thumb touch start.
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carouselScrollBar.onThumbTouchStart = { [weak self] scrubberId in
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guard let self else { return }
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updateScrollPosition(position: scrubberId, callbackText:"onThumbTouchStart")
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}
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/// will be called when the thumb touch end.
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carouselScrollBar.onThumbTouchEnd = { [weak self] scrubberId in
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guard let self else { return }
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updateScrollPosition(position: scrubberId, callbackText:"onThumbTouchEnd")
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}
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}
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func updatePaginationControls() {
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containerView.surface = surface
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showPaginationControls()
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previousButton.kind = pagination.kind
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previousButton.floating = pagination.floating
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nextButton.kind = pagination.kind
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nextButton.floating = pagination.floating
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previousButton.surface = surface
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nextButton.surface = surface
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}
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func updatePaginationInset() {
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prevButtonLeadingConstraint?.isActive = false
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nextButtonTrailingConstraint?.isActive = false
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prevButtonLeadingConstraint = previousButton.leadingAnchor.constraint(equalTo: scrollContainerView.leadingAnchor, constant: paginationInset)
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nextButtonTrailingConstraint = nextButton.trailingAnchor.constraint(equalTo: scrollContainerView.trailingAnchor, constant: -paginationInset)
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prevButtonLeadingConstraint?.isActive = true
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nextButtonTrailingConstraint?.isActive = true
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}
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func getSlotWidth() {
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let actualWidth = containerView.frame.size.width
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minimumSlotWidth = actualWidth - (CGFloat(layout.value) * gutter.value)
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switch peek {
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case .standard:
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minimumSlotWidth = minimumSlotWidth - (3*peekMinimum)
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case .minimum:
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minimumSlotWidth = minimumSlotWidth - peekMinimum
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case .none:
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break
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}
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minimumSlotWidth = minimumSlotWidth / CGFloat(layout.value)
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}
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func nextButtonClick() {
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carouselScrollBar.position = carouselScrollBar.position+1
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showPaginationControls()
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updateScrollPosition(position: carouselScrollBar.position, callbackText:"pageControlClicks")
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}
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func previousButtonClick() {
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carouselScrollBar.position = carouselScrollBar.position-1
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showPaginationControls()
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updateScrollPosition(position: carouselScrollBar.position, callbackText:"pageControlClicks")
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}
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func updateScrollPosition(position: Int, callbackText: String) {
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if carouselScrollBar.numberOfSlides > 0 {
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let contentOffsetWidth = scrollView.contentSize.width
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let totalPositions = totalPositions()
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let multiplier: Float = (position == 1) ? 0 : Float((position)-1) / Float(totalPositions)
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let xPos = (position == totalPositions) ? (contentOffsetWidth - containerView.frame.size.width) : CGFloat(Float(contentOffsetWidth) * multiplier)
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carouselScrollBar.scrubberId = position
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let yPos = scrollView.contentOffset.y
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scrollView.setContentOffset(CGPoint(x: xPos, y: yPos), animated: true)
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showPaginationControls()
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}
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}
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private func totalPositions() -> Int {
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return Int (ceil (Double(carouselScrollBar.numberOfSlides) / Double(_layout.value)))
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}
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func showPaginationControls() {
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if carouselScrollBar.numberOfSlides == _layout.value {
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previousButton.isHidden = true
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nextButton.isHidden = true
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} else {
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previousButton.isHidden = (carouselScrollBar.position == 1) || (paginationDisplay == .none)
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nextButton.isHidden = (carouselScrollBar.position == totalPositions()) || (paginationDisplay == .none)
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}
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}
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}
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