carousel_options.dart

import 'package:flutter/material.dart';

enum CarouselPageChangedReason { timed, manual, controller }

enum CenterPageEnlargeStrategy { scale, height, zoom }

class CarouselOptions {
  /// Set carousel height and overrides any existing [aspectRatio].
  final double? height;

  /// Aspect ratio is used if no height have been declared.
  ///
  /// Defaults to 16:9 aspect ratio.
  final double aspectRatio;

  /// The fraction of the viewport that each page should occupy.
  ///
  /// Defaults to 0.8, which means each page fills 80% of the carousel.
  final double viewportFraction;

  /// The initial page to show when first creating the [CarouselSlider].
  ///
  /// Defaults to 0.
  final int initialPage;

  ///Determines if carousel should loop infinitely or be limited to item length.
  ///
  ///Defaults to true, i.e. infinite loop.
  ///
  /// TODO: fix infinite scroll using expandable_view package
  final bool enableInfiniteScroll;

  ///Determines if carousel should loop to the closest occurence of requested page.
  ///
  ///Defaults to true.
  final bool animateToClosest;

  /// Reverse the order of items if set to true.
  ///
  /// Defaults to false.
  final bool reverse;

  /// Enables auto play, sliding one page at a time.
  ///
  /// Use [autoPlayInterval] to determent the frequency of slides.
  /// Defaults to false.
  final bool autoPlay;

  /// Sets Duration to determent the frequency of slides when
  ///
  /// [autoPlay] is set to true.
  /// Defaults to 4 seconds.
  final Duration autoPlayInterval;

  /// The animation duration between two transitioning pages while in auto playback.
  ///
  /// Defaults to 800 ms.
  final Duration autoPlayAnimationDuration;

  /// Determines the animation curve physics.
  ///
  /// Defaults to [Curves.fastOutSlowIn].
  final Curve autoPlayCurve;

  /// Determines if current page should be larger than the side images,
  /// creating a feeling of depth in the carousel.
  ///
  /// Defaults to false.
  final bool? enlargeCenterPage;

  /// The axis along which the page view scrolls.
  ///
  /// Defaults to [Axis.horizontal].
  final Axis scrollDirection;

  /// Called whenever the page in the center of the viewport changes.
  final Function(int index, CarouselPageChangedReason reason)? onPageChanged;

  /// Called whenever the carousel is scrolled
  final ValueChanged<double?>? onScrolled;

  /// How the carousel should respond to user input.
  ///
  /// For example, determines how the items continues to animate after the
  /// user stops dragging the page view.
  ///
  /// The physics are modified to snap to page boundaries using
  /// [PageScrollPhysics] prior to being used.
  ///
  /// Defaults to matching platform conventions.
  final ScrollPhysics? scrollPhysics;

  /// Set to false to disable page snapping, useful for custom scroll behavior.
  ///
  /// Default to `true`.
  final bool pageSnapping;

  /// If `true`, the auto play function will be paused when user is interacting with
  /// the carousel, and will be resumed when user finish interacting.
  /// Default to `true`.
  final bool pauseAutoPlayOnTouch;

  /// If `true`, the auto play function will be paused when user is calling
  /// pageController's `nextPage` or `previousPage` or `animateToPage` method.
  /// And after the animation complete, the auto play will be resumed.
  /// Default to `true`.
  final bool pauseAutoPlayOnManualNavigate;

  /// If `enableInfiniteScroll` is `false`, and `autoPlay` is `true`, this option
  /// decide the carousel should go to the first item when it reach the last item or not.
  /// If set to `true`, the auto play will be paused when it reach the last item.
  /// If set to `false`, the auto play function will animate to the first item when it was
  /// in the last item.
  final bool pauseAutoPlayInFiniteScroll;

  /// Pass a `PageStoragekey` if you want to keep the pageview's position when it was recreated.
  final PageStorageKey? pageViewKey;

  /// Use [enlargeStrategy] to determine which method to enlarge the center page.
  final CenterPageEnlargeStrategy enlargeStrategy;

  /// How much the pages next to the center page will be scaled down.
  /// If `enlargeCenterPage` is false, this property has no effect.
  final double enlargeFactor;

  /// Whether or not to disable the `Center` widget for each slide.
  final bool disableCenter;

  /// Whether to add padding to both ends of the list.
  /// If this is set to true and [viewportFraction] < 1.0, padding will be added such that the first and last child slivers will be in the center of the viewport when scrolled all the way to the start or end, respectively.
  /// If [viewportFraction] >= 1.0, this property has no effect.
  /// This property defaults to true and must not be null.
  final bool padEnds;

  /// Exposed clipBehavior of PageView
  final Clip clipBehavior;

  CarouselOptions({
    this.height,
    this.aspectRatio: 16 / 9,
    this.viewportFraction: 0.8,
    this.initialPage: 0,
    this.animateToClosest: true,
    this.reverse: false,
    this.autoPlay: false,
    this.autoPlayInterval: const Duration(seconds: 4),
    this.autoPlayAnimationDuration = const Duration(milliseconds: 800),
    this.autoPlayCurve: Curves.fastOutSlowIn,
    this.enlargeCenterPage = false,
    this.onPageChanged,
    this.onScrolled,
    this.scrollPhysics,
    this.pageSnapping = true,
    this.scrollDirection: Axis.horizontal,
    this.pauseAutoPlayOnTouch: true,
    this.pauseAutoPlayOnManualNavigate: true,
    this.pauseAutoPlayInFiniteScroll: false,
    this.pageViewKey,
    this.enlargeStrategy: CenterPageEnlargeStrategy.scale,
    this.enlargeFactor: 0.3,
    this.disableCenter: false,
    this.padEnds = true,
    this.clipBehavior: Clip.hardEdge,
  }) : this.enableInfiniteScroll = false;

  ///Generate new [CarouselOptions] based on old ones.

  CarouselOptions copyWith(
          {double? height,
          double? aspectRatio,
          double? viewportFraction,
          int? initialPage,
          bool? reverse,
          bool? autoPlay,
          Duration? autoPlayInterval,
          Duration? autoPlayAnimationDuration,
          Curve? autoPlayCurve,
          bool? enlargeCenterPage,
          Function(int index, CarouselPageChangedReason reason)? onPageChanged,
          ValueChanged<double?>? onScrolled,
          ScrollPhysics? scrollPhysics,
          bool? pageSnapping,
          Axis? scrollDirection,
          bool? pauseAutoPlayOnTouch,
          bool? pauseAutoPlayOnManualNavigate,
          bool? pauseAutoPlayInFiniteScroll,
          PageStorageKey? pageViewKey,
          CenterPageEnlargeStrategy? enlargeStrategy,
          double? enlargeFactor,
          bool? disableCenter,
          Clip? clipBehavior,
          bool? padEnds}) =>
      CarouselOptions(
        height: height ?? this.height,
        aspectRatio: aspectRatio ?? this.aspectRatio,
        viewportFraction: viewportFraction ?? this.viewportFraction,
        initialPage: initialPage ?? this.initialPage,
        reverse: reverse ?? this.reverse,
        autoPlay: autoPlay ?? this.autoPlay,
        autoPlayInterval: autoPlayInterval ?? this.autoPlayInterval,
        autoPlayAnimationDuration:
            autoPlayAnimationDuration ?? this.autoPlayAnimationDuration,
        autoPlayCurve: autoPlayCurve ?? this.autoPlayCurve,
        enlargeCenterPage: enlargeCenterPage ?? this.enlargeCenterPage,
        onPageChanged: onPageChanged ?? this.onPageChanged,
        onScrolled: onScrolled ?? this.onScrolled,
        scrollPhysics: scrollPhysics ?? this.scrollPhysics,
        pageSnapping: pageSnapping ?? this.pageSnapping,
        scrollDirection: scrollDirection ?? this.scrollDirection,
        pauseAutoPlayOnTouch: pauseAutoPlayOnTouch ?? this.pauseAutoPlayOnTouch,
        pauseAutoPlayOnManualNavigate:
            pauseAutoPlayOnManualNavigate ?? this.pauseAutoPlayOnManualNavigate,
        pauseAutoPlayInFiniteScroll:
            pauseAutoPlayInFiniteScroll ?? this.pauseAutoPlayInFiniteScroll,
        pageViewKey: pageViewKey ?? this.pageViewKey,
        enlargeStrategy: enlargeStrategy ?? this.enlargeStrategy,
        enlargeFactor: enlargeFactor ?? this.enlargeFactor,
        disableCenter: disableCenter ?? this.disableCenter,
        clipBehavior: clipBehavior ?? this.clipBehavior,
        padEnds: padEnds ?? this.padEnds,
      );
}