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osu-lazer/osu.Game/Screens/Select/BeatmapCarousel.cs
2020-07-13 13:08:41 +09:00

911 lines
34 KiB
C#

// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.
using osuTK;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Containers;
using System;
using System.Collections.Generic;
using System.Linq;
using osu.Game.Configuration;
using osuTK.Input;
using osu.Framework.Utils;
using System.Diagnostics;
using osu.Framework.Allocation;
using osu.Framework.Bindables;
using osu.Framework.Caching;
using osu.Framework.Threading;
using osu.Framework.Extensions.IEnumerableExtensions;
using osu.Framework.Input.Bindings;
using osu.Framework.Input.Events;
using osu.Game.Beatmaps;
using osu.Game.Extensions;
using osu.Game.Graphics.Containers;
using osu.Game.Graphics.Cursor;
using osu.Game.Input.Bindings;
using osu.Game.Screens.Select.Carousel;
namespace osu.Game.Screens.Select
{
public class BeatmapCarousel : CompositeDrawable, IKeyBindingHandler<GlobalAction>
{
/// <summary>
/// Height of the area above the carousel that should be treated as visible due to transparency of elements in front of it.
/// </summary>
public float BleedTop { get; set; }
/// <summary>
/// Height of the area below the carousel that should be treated as visible due to transparency of elements in front of it.
/// </summary>
public float BleedBottom { get; set; }
/// <summary>
/// Triggered when the <see cref="BeatmapSets"/> loaded change and are completely loaded.
/// </summary>
public Action BeatmapSetsChanged;
/// <summary>
/// The currently selected beatmap.
/// </summary>
public BeatmapInfo SelectedBeatmap => selectedBeatmap?.Beatmap;
private CarouselBeatmap selectedBeatmap => selectedBeatmapSet?.Beatmaps.FirstOrDefault(s => s.State.Value == CarouselItemState.Selected);
/// <summary>
/// The currently selected beatmap set.
/// </summary>
public BeatmapSetInfo SelectedBeatmapSet => selectedBeatmapSet?.BeatmapSet;
/// <summary>
/// A function to optionally decide on a recommended difficulty from a beatmap set.
/// </summary>
public Func<IEnumerable<BeatmapInfo>, BeatmapInfo> GetRecommendedBeatmap;
private CarouselBeatmapSet selectedBeatmapSet;
/// <summary>
/// Raised when the <see cref="SelectedBeatmap"/> is changed.
/// </summary>
public Action<BeatmapInfo> SelectionChanged;
public override bool HandleNonPositionalInput => AllowSelection;
public override bool HandlePositionalInput => AllowSelection;
public override bool PropagatePositionalInputSubTree => AllowSelection;
public override bool PropagateNonPositionalInputSubTree => AllowSelection;
/// <summary>
/// Whether carousel items have completed asynchronously loaded.
/// </summary>
public bool BeatmapSetsLoaded { get; private set; }
private readonly CarouselScrollContainer scroll;
private IEnumerable<CarouselBeatmapSet> beatmapSets => root.Children.OfType<CarouselBeatmapSet>();
// todo: only used for testing, maybe remove.
public IEnumerable<BeatmapSetInfo> BeatmapSets
{
get => beatmapSets.Select(g => g.BeatmapSet);
set => loadBeatmapSets(value);
}
private void loadBeatmapSets(IEnumerable<BeatmapSetInfo> beatmapSets)
{
CarouselRoot newRoot = new CarouselRoot(this);
beatmapSets.Select(createCarouselSet).Where(g => g != null).ForEach(newRoot.AddChild);
// preload drawables as the ctor overhead is quite high currently.
_ = newRoot.Drawables;
root = newRoot;
if (selectedBeatmapSet != null && !beatmapSets.Contains(selectedBeatmapSet.BeatmapSet))
selectedBeatmapSet = null;
scrollableContent.Clear(false);
itemsCache.Invalidate();
scrollPositionCache.Invalidate();
// apply any pending filter operation that may have been delayed (see applyActiveCriteria's scheduling behaviour when BeatmapSetsLoaded is false).
FlushPendingFilterOperations();
// Run on late scheduler want to ensure this runs after all pending UpdateBeatmapSet / RemoveBeatmapSet operations are run.
SchedulerAfterChildren.Add(() =>
{
BeatmapSetsChanged?.Invoke();
BeatmapSetsLoaded = true;
});
}
private readonly List<float> yPositions = new List<float>();
private readonly Cached itemsCache = new Cached();
private readonly Cached scrollPositionCache = new Cached();
private readonly Container<DrawableCarouselItem> scrollableContent;
public Bindable<bool> RightClickScrollingEnabled = new Bindable<bool>();
public Bindable<RandomSelectAlgorithm> RandomAlgorithm = new Bindable<RandomSelectAlgorithm>();
private readonly List<CarouselBeatmapSet> previouslyVisitedRandomSets = new List<CarouselBeatmapSet>();
private readonly Stack<CarouselBeatmap> randomSelectedBeatmaps = new Stack<CarouselBeatmap>();
protected List<DrawableCarouselItem> Items = new List<DrawableCarouselItem>();
private CarouselRoot root;
private IBindable<WeakReference<BeatmapSetInfo>> itemUpdated;
private IBindable<WeakReference<BeatmapSetInfo>> itemRemoved;
private IBindable<WeakReference<BeatmapInfo>> itemHidden;
private IBindable<WeakReference<BeatmapInfo>> itemRestored;
public BeatmapCarousel()
{
root = new CarouselRoot(this);
InternalChild = new OsuContextMenuContainer
{
RelativeSizeAxes = Axes.Both,
Child = scroll = new CarouselScrollContainer
{
Masking = false,
RelativeSizeAxes = Axes.Both,
Child = scrollableContent = new Container<DrawableCarouselItem>
{
RelativeSizeAxes = Axes.X,
}
}
};
}
[Resolved]
private BeatmapManager beatmaps { get; set; }
[BackgroundDependencyLoader(permitNulls: true)]
private void load(OsuConfigManager config)
{
config.BindWith(OsuSetting.RandomSelectAlgorithm, RandomAlgorithm);
config.BindWith(OsuSetting.SongSelectRightMouseScroll, RightClickScrollingEnabled);
RightClickScrollingEnabled.ValueChanged += enabled => scroll.RightMouseScrollbar = enabled.NewValue;
RightClickScrollingEnabled.TriggerChange();
itemUpdated = beatmaps.ItemUpdated.GetBoundCopy();
itemUpdated.BindValueChanged(beatmapUpdated);
itemRemoved = beatmaps.ItemRemoved.GetBoundCopy();
itemRemoved.BindValueChanged(beatmapRemoved);
itemHidden = beatmaps.BeatmapHidden.GetBoundCopy();
itemHidden.BindValueChanged(beatmapHidden);
itemRestored = beatmaps.BeatmapRestored.GetBoundCopy();
itemRestored.BindValueChanged(beatmapRestored);
loadBeatmapSets(GetLoadableBeatmaps());
}
protected virtual IEnumerable<BeatmapSetInfo> GetLoadableBeatmaps() => beatmaps.GetAllUsableBeatmapSetsEnumerable(IncludedDetails.AllButFiles);
public void RemoveBeatmapSet(BeatmapSetInfo beatmapSet) => Schedule(() =>
{
var existingSet = beatmapSets.FirstOrDefault(b => b.BeatmapSet.ID == beatmapSet.ID);
if (existingSet == null)
return;
root.RemoveChild(existingSet);
itemsCache.Invalidate();
});
public void UpdateBeatmapSet(BeatmapSetInfo beatmapSet) => Schedule(() =>
{
int? previouslySelectedID = null;
CarouselBeatmapSet existingSet = beatmapSets.FirstOrDefault(b => b.BeatmapSet.ID == beatmapSet.ID);
// If the selected beatmap is about to be removed, store its ID so it can be re-selected if required
if (existingSet?.State?.Value == CarouselItemState.Selected)
previouslySelectedID = selectedBeatmap?.Beatmap.ID;
var newSet = createCarouselSet(beatmapSet);
if (existingSet != null)
root.RemoveChild(existingSet);
if (newSet == null)
{
itemsCache.Invalidate();
return;
}
root.AddChild(newSet);
// only reset scroll position if already near the scroll target.
// without this, during a large beatmap import it is impossible to navigate the carousel.
applyActiveCriteria(false, alwaysResetScrollPosition: false);
// check if we can/need to maintain our current selection.
if (previouslySelectedID != null)
select((CarouselItem)newSet.Beatmaps.FirstOrDefault(b => b.Beatmap.ID == previouslySelectedID) ?? newSet);
itemsCache.Invalidate();
Schedule(() => BeatmapSetsChanged?.Invoke());
});
/// <summary>
/// Selects a given beatmap on the carousel.
/// </summary>
/// <param name="beatmap">The beatmap to select.</param>
/// <param name="bypassFilters">Whether to select the beatmap even if it is filtered (i.e., not visible on carousel).</param>
/// <returns>True if a selection was made, False if it wasn't.</returns>
public bool SelectBeatmap(BeatmapInfo beatmap, bool bypassFilters = true)
{
// ensure that any pending events from BeatmapManager have been run before attempting a selection.
Scheduler.Update();
if (beatmap?.Hidden != false)
return false;
foreach (CarouselBeatmapSet set in beatmapSets)
{
if (!bypassFilters && set.Filtered.Value)
continue;
var item = set.Beatmaps.FirstOrDefault(p => p.Beatmap.Equals(beatmap));
if (item == null)
// The beatmap that needs to be selected doesn't exist in this set
continue;
if (!bypassFilters && item.Filtered.Value)
return false;
select(item);
// if we got here and the set is filtered, it means we were bypassing filters.
// in this case, reapplying the filter is necessary to ensure the panel is in the correct place
// (since it is forcefully being included in the carousel).
if (set.Filtered.Value)
{
Debug.Assert(bypassFilters);
applyActiveCriteria(false);
}
return true;
}
return false;
}
/// <summary>
/// Increment selection in the carousel in a chosen direction.
/// </summary>
/// <param name="direction">The direction to increment. Negative is backwards.</param>
/// <param name="skipDifficulties">Whether to skip individual difficulties and only increment over full groups.</param>
public void SelectNext(int direction = 1, bool skipDifficulties = true)
{
if (beatmapSets.All(s => s.Filtered.Value))
return;
if (skipDifficulties)
selectNextSet(direction, true);
else
selectNextDifficulty(direction);
}
private void selectNextSet(int direction, bool skipDifficulties)
{
var unfilteredSets = beatmapSets.Where(s => !s.Filtered.Value).ToList();
var nextSet = unfilteredSets[(unfilteredSets.IndexOf(selectedBeatmapSet) + direction + unfilteredSets.Count) % unfilteredSets.Count];
if (skipDifficulties)
select(nextSet);
else
select(direction > 0 ? nextSet.Beatmaps.First(b => !b.Filtered.Value) : nextSet.Beatmaps.Last(b => !b.Filtered.Value));
}
private void selectNextDifficulty(int direction)
{
if (selectedBeatmap == null)
return;
var unfilteredDifficulties = selectedBeatmapSet.Children.Where(s => !s.Filtered.Value).ToList();
int index = unfilteredDifficulties.IndexOf(selectedBeatmap);
if (index + direction < 0 || index + direction >= unfilteredDifficulties.Count)
selectNextSet(direction, false);
else
select(unfilteredDifficulties[index + direction]);
}
/// <summary>
/// Select the next beatmap in the random sequence.
/// </summary>
/// <returns>True if a selection could be made, else False.</returns>
public bool SelectNextRandom()
{
if (!AllowSelection)
return false;
var visibleSets = beatmapSets.Where(s => !s.Filtered.Value).ToList();
if (!visibleSets.Any())
return false;
if (selectedBeatmap != null)
{
randomSelectedBeatmaps.Push(selectedBeatmap);
// when performing a random, we want to add the current set to the previously visited list
// else the user may be "randomised" to the existing selection.
if (previouslyVisitedRandomSets.LastOrDefault() != selectedBeatmapSet)
previouslyVisitedRandomSets.Add(selectedBeatmapSet);
}
CarouselBeatmapSet set;
if (RandomAlgorithm.Value == RandomSelectAlgorithm.RandomPermutation)
{
var notYetVisitedSets = visibleSets.Except(previouslyVisitedRandomSets).ToList();
if (!notYetVisitedSets.Any())
{
previouslyVisitedRandomSets.RemoveAll(s => visibleSets.Contains(s));
notYetVisitedSets = visibleSets;
}
set = notYetVisitedSets.ElementAt(RNG.Next(notYetVisitedSets.Count));
previouslyVisitedRandomSets.Add(set);
}
else
set = visibleSets.ElementAt(RNG.Next(visibleSets.Count));
select(set);
return true;
}
public void SelectPreviousRandom()
{
while (randomSelectedBeatmaps.Any())
{
var beatmap = randomSelectedBeatmaps.Pop();
if (!beatmap.Filtered.Value)
{
if (RandomAlgorithm.Value == RandomSelectAlgorithm.RandomPermutation)
previouslyVisitedRandomSets.Remove(selectedBeatmapSet);
select(beatmap);
break;
}
}
}
private void select(CarouselItem item)
{
if (!AllowSelection)
return;
if (item == null) return;
item.State.Value = CarouselItemState.Selected;
}
private FilterCriteria activeCriteria = new FilterCriteria();
protected ScheduledDelegate PendingFilter;
public bool AllowSelection = true;
/// <summary>
/// Half the height of the visible content.
/// <remarks>
/// This is different from the height of <see cref="ScrollContainer{T}"/>.displayableContent, since
/// the beatmap carousel bleeds into the <see cref="FilterControl"/> and the <see cref="Footer"/>
/// </remarks>
/// </summary>
private float visibleHalfHeight => (DrawHeight + BleedBottom + BleedTop) / 2;
/// <summary>
/// The position of the lower visible bound with respect to the current scroll position.
/// </summary>
private float visibleBottomBound => scroll.Current + DrawHeight + BleedBottom;
/// <summary>
/// The position of the upper visible bound with respect to the current scroll position.
/// </summary>
private float visibleUpperBound => scroll.Current - BleedTop;
public void FlushPendingFilterOperations()
{
if (PendingFilter?.Completed == false)
{
applyActiveCriteria(false);
Update();
}
}
public void Filter(FilterCriteria newCriteria, bool debounce = true)
{
if (newCriteria != null)
activeCriteria = newCriteria;
applyActiveCriteria(debounce);
}
private void applyActiveCriteria(bool debounce, bool alwaysResetScrollPosition = true)
{
PendingFilter?.Cancel();
PendingFilter = null;
if (debounce)
PendingFilter = Scheduler.AddDelayed(perform, 250);
else
{
// if initial load is not yet finished, this will be run inline in loadBeatmapSets to ensure correct order of operation.
if (!BeatmapSetsLoaded)
PendingFilter = Schedule(perform);
else
perform();
}
void perform()
{
PendingFilter = null;
root.Filter(activeCriteria);
itemsCache.Invalidate();
if (alwaysResetScrollPosition || !scroll.UserScrolling)
ScrollToSelected();
}
}
private float? scrollTarget;
/// <summary>
/// Scroll to the current <see cref="SelectedBeatmap"/>.
/// </summary>
public void ScrollToSelected() => scrollPositionCache.Invalidate();
#region Key / button selection logic
protected override bool OnKeyDown(KeyDownEvent e)
{
switch (e.Key)
{
case Key.Left:
if (!e.Repeat)
beginRepeatSelection(() => SelectNext(-1, true), e.Key);
return true;
case Key.Right:
if (!e.Repeat)
beginRepeatSelection(() => SelectNext(1, true), e.Key);
return true;
}
return false;
}
protected override void OnKeyUp(KeyUpEvent e)
{
switch (e.Key)
{
case Key.Left:
case Key.Right:
endRepeatSelection(e.Key);
break;
}
base.OnKeyUp(e);
}
public bool OnPressed(GlobalAction action)
{
switch (action)
{
case GlobalAction.SelectNext:
beginRepeatSelection(() => SelectNext(1, false), action);
return true;
case GlobalAction.SelectPrevious:
beginRepeatSelection(() => SelectNext(-1, false), action);
return true;
}
return false;
}
public void OnReleased(GlobalAction action)
{
switch (action)
{
case GlobalAction.SelectNext:
case GlobalAction.SelectPrevious:
endRepeatSelection(action);
break;
}
}
private ScheduledDelegate repeatDelegate;
private object lastRepeatSource;
/// <summary>
/// Begin repeating the specified selection action.
/// </summary>
/// <param name="action">The action to perform.</param>
/// <param name="source">The source of the action. Used in conjunction with <see cref="endRepeatSelection"/> to only cancel the correct action (most recently pressed key).</param>
private void beginRepeatSelection(Action action, object source)
{
endRepeatSelection();
lastRepeatSource = source;
repeatDelegate = this.BeginKeyRepeat(Scheduler, action);
}
private void endRepeatSelection(object source = null)
{
// only the most recent source should be able to cancel the current action.
if (source != null && !EqualityComparer<object>.Default.Equals(lastRepeatSource, source))
return;
repeatDelegate?.Cancel();
repeatDelegate = null;
lastRepeatSource = null;
}
#endregion
protected override void Update()
{
base.Update();
if (!itemsCache.IsValid)
updateItems();
// Remove all items that should no longer be on-screen
scrollableContent.RemoveAll(p => p.Y < visibleUpperBound - p.DrawHeight || p.Y > visibleBottomBound || !p.IsPresent);
// Find index range of all items that should be on-screen
Trace.Assert(Items.Count == yPositions.Count);
int firstIndex = yPositions.BinarySearch(visibleUpperBound - DrawableCarouselItem.MAX_HEIGHT);
if (firstIndex < 0) firstIndex = ~firstIndex;
int lastIndex = yPositions.BinarySearch(visibleBottomBound);
if (lastIndex < 0) lastIndex = ~lastIndex;
int notVisibleCount = 0;
// Add those items within the previously found index range that should be displayed.
for (int i = firstIndex; i < lastIndex; ++i)
{
DrawableCarouselItem item = Items[i];
if (!item.Item.Visible)
{
if (!item.IsPresent)
notVisibleCount++;
continue;
}
float depth = i + (item is DrawableCarouselBeatmapSet ? -Items.Count : 0);
// Only add if we're not already part of the content.
if (!scrollableContent.Contains(item))
{
// Makes sure headers are always _below_ items,
// and depth flows downward.
item.Depth = depth;
switch (item.LoadState)
{
case LoadState.NotLoaded:
LoadComponentAsync(item);
break;
case LoadState.Loading:
break;
default:
scrollableContent.Add(item);
break;
}
}
else
{
scrollableContent.ChangeChildDepth(item, depth);
}
}
// this is not actually useful right now, but once we have groups may well be.
if (notVisibleCount > 50)
itemsCache.Invalidate();
// Update externally controlled state of currently visible items
// (e.g. x-offset and opacity).
foreach (DrawableCarouselItem p in scrollableContent.Children)
updateItem(p);
}
protected override void UpdateAfterChildren()
{
base.UpdateAfterChildren();
if (!scrollPositionCache.IsValid)
updateScrollPosition();
}
protected override void Dispose(bool isDisposing)
{
base.Dispose(isDisposing);
// aggressively dispose "off-screen" items to reduce GC pressure.
foreach (var i in Items)
i.Dispose();
}
private void beatmapRemoved(ValueChangedEvent<WeakReference<BeatmapSetInfo>> weakItem)
{
if (weakItem.NewValue.TryGetTarget(out var item))
RemoveBeatmapSet(item);
}
private void beatmapUpdated(ValueChangedEvent<WeakReference<BeatmapSetInfo>> weakItem)
{
if (weakItem.NewValue.TryGetTarget(out var item))
UpdateBeatmapSet(item);
}
private void beatmapRestored(ValueChangedEvent<WeakReference<BeatmapInfo>> weakItem)
{
if (weakItem.NewValue.TryGetTarget(out var b))
UpdateBeatmapSet(beatmaps.QueryBeatmapSet(s => s.ID == b.BeatmapSetInfoID));
}
private void beatmapHidden(ValueChangedEvent<WeakReference<BeatmapInfo>> weakItem)
{
if (weakItem.NewValue.TryGetTarget(out var b))
UpdateBeatmapSet(beatmaps.QueryBeatmapSet(s => s.ID == b.BeatmapSetInfoID));
}
private CarouselBeatmapSet createCarouselSet(BeatmapSetInfo beatmapSet)
{
if (beatmapSet.Beatmaps.All(b => b.Hidden))
return null;
// todo: remove the need for this.
foreach (var b in beatmapSet.Beatmaps)
b.Metadata ??= beatmapSet.Metadata;
var set = new CarouselBeatmapSet(beatmapSet)
{
GetRecommendedBeatmap = beatmaps => GetRecommendedBeatmap?.Invoke(beatmaps)
};
foreach (var c in set.Beatmaps)
{
c.State.ValueChanged += state =>
{
if (state.NewValue == CarouselItemState.Selected)
{
selectedBeatmapSet = set;
SelectionChanged?.Invoke(c.Beatmap);
itemsCache.Invalidate();
ScrollToSelected();
}
};
}
return set;
}
/// <summary>
/// Computes the target Y positions for every item in the carousel.
/// </summary>
/// <returns>The Y position of the currently selected item.</returns>
private void updateItems()
{
Items = root.Drawables.ToList();
yPositions.Clear();
float currentY = visibleHalfHeight;
DrawableCarouselBeatmapSet lastSet = null;
scrollTarget = null;
foreach (DrawableCarouselItem d in Items)
{
if (d.IsPresent)
{
switch (d)
{
case DrawableCarouselBeatmapSet set:
{
lastSet = set;
set.MoveToX(set.Item.State.Value == CarouselItemState.Selected ? -100 : 0, 500, Easing.OutExpo);
set.MoveToY(currentY, 750, Easing.OutExpo);
break;
}
case DrawableCarouselBeatmap beatmap:
{
if (beatmap.Item.State.Value == CarouselItemState.Selected)
// scroll position at currentY makes the set panel appear at the very top of the carousel's screen space
// move down by half of visible height (height of the carousel's visible extent, including semi-transparent areas)
// then reapply the top semi-transparent area (because carousel's screen space starts below it)
// and finally add half of the panel's own height to achieve vertical centering of the panel itself
scrollTarget = currentY - visibleHalfHeight + BleedTop + beatmap.DrawHeight / 2;
void performMove(float y, float? startY = null)
{
if (startY != null) beatmap.MoveTo(new Vector2(0, startY.Value));
beatmap.MoveToX(beatmap.Item.State.Value == CarouselItemState.Selected ? -50 : 0, 500, Easing.OutExpo);
beatmap.MoveToY(y, 750, Easing.OutExpo);
}
Debug.Assert(lastSet != null);
float? setY = null;
if (!d.IsLoaded || beatmap.Alpha == 0) // can't use IsPresent due to DrawableCarouselItem override.
setY = lastSet.Y + lastSet.DrawHeight + 5;
if (d.IsLoaded)
performMove(currentY, setY);
else
{
float y = currentY;
d.OnLoadComplete += _ => performMove(y, setY);
}
break;
}
}
}
yPositions.Add(currentY);
if (d.Item.Visible)
currentY += d.DrawHeight + 5;
}
currentY += visibleHalfHeight;
scrollableContent.Height = currentY;
if (BeatmapSetsLoaded && (selectedBeatmapSet == null || selectedBeatmap == null || selectedBeatmapSet.State.Value != CarouselItemState.Selected))
{
selectedBeatmapSet = null;
SelectionChanged?.Invoke(null);
}
itemsCache.Validate();
}
private bool firstScroll = true;
private void updateScrollPosition()
{
if (scrollTarget != null)
{
if (firstScroll)
{
// reduce movement when first displaying the carousel.
scroll.ScrollTo(scrollTarget.Value - 200, false);
firstScroll = false;
}
scroll.ScrollTo(scrollTarget.Value);
scrollPositionCache.Validate();
}
}
/// <summary>
/// Computes the x-offset of currently visible items. Makes the carousel appear round.
/// </summary>
/// <param name="dist">
/// Vertical distance from the center of the carousel container
/// ranging from -1 to 1.
/// </param>
/// <param name="halfHeight">Half the height of the carousel container.</param>
private static float offsetX(float dist, float halfHeight)
{
// The radius of the circle the carousel moves on.
const float circle_radius = 3;
float discriminant = MathF.Max(0, circle_radius * circle_radius - dist * dist);
float x = (circle_radius - MathF.Sqrt(discriminant)) * halfHeight;
return 125 + x;
}
/// <summary>
/// Update a item's x position and multiplicative alpha based on its y position and
/// the current scroll position.
/// </summary>
/// <param name="p">The item to be updated.</param>
private void updateItem(DrawableCarouselItem p)
{
float itemDrawY = p.Position.Y - visibleUpperBound + p.DrawHeight / 2;
float dist = Math.Abs(1f - itemDrawY / visibleHalfHeight);
// Setting the origin position serves as an additive position on top of potential
// local transformation we may want to apply (e.g. when a item gets selected, we
// may want to smoothly transform it leftwards.)
p.OriginPosition = new Vector2(-offsetX(dist, visibleHalfHeight), 0);
// We are applying a multiplicative alpha (which is internally done by nesting an
// additional container and setting that container's alpha) such that we can
// layer transformations on top, with a similar reasoning to the previous comment.
p.SetMultiplicativeAlpha(Math.Clamp(1.75f - 1.5f * dist, 0, 1));
}
private class CarouselRoot : CarouselGroupEagerSelect
{
private readonly BeatmapCarousel carousel;
public CarouselRoot(BeatmapCarousel carousel)
{
// root should always remain selected. if not, PerformSelection will not be called.
State.Value = CarouselItemState.Selected;
State.ValueChanged += state => State.Value = CarouselItemState.Selected;
this.carousel = carousel;
}
protected override void PerformSelection()
{
if (LastSelected == null || LastSelected.Filtered.Value)
carousel?.SelectNextRandom();
else
base.PerformSelection();
}
}
private class CarouselScrollContainer : OsuScrollContainer
{
private bool rightMouseScrollBlocked;
/// <summary>
/// Whether the last scroll event was user triggered, directly on the scroll container.
/// </summary>
public bool UserScrolling { get; private set; }
protected override void OnUserScroll(float value, bool animated = true, double? distanceDecay = default)
{
UserScrolling = true;
base.OnUserScroll(value, animated, distanceDecay);
}
public new void ScrollTo(float value, bool animated = true, double? distanceDecay = null)
{
UserScrolling = false;
base.ScrollTo(value, animated, distanceDecay);
}
protected override bool OnMouseDown(MouseDownEvent e)
{
if (e.Button == MouseButton.Right)
{
// we need to block right click absolute scrolling when hovering a carousel item so context menus can display.
// this can be reconsidered when we have an alternative to right click scrolling.
if (GetContainingInputManager().HoveredDrawables.OfType<DrawableCarouselItem>().Any())
{
rightMouseScrollBlocked = true;
return false;
}
}
rightMouseScrollBlocked = false;
return base.OnMouseDown(e);
}
protected override bool OnDragStart(DragStartEvent e)
{
if (rightMouseScrollBlocked)
return false;
return base.OnDragStart(e);
}
}
}
}