com.unity.uiextensions/Scripts/Layout/FancyScrollView/Scroller/Scroller.cs

415 lines
13 KiB
C#

/// Credit setchi (https://github.com/setchi)
/// Sourced from - https://github.com/setchi/FancyScrollView
using System;
using UnityEngine.EventSystems;
using UnityEngine.UI.Extensions.EasingCore;
namespace UnityEngine.UI.Extensions
{
public class Scroller : UIBehaviour, IBeginDragHandler, IEndDragHandler, IDragHandler
{
[SerializeField] RectTransform viewport = default;
[SerializeField] ScrollDirection scrollDirection = ScrollDirection.Vertical;
[SerializeField] MovementType movementType = MovementType.Elastic;
[SerializeField] float elasticity = 0.1f;
[SerializeField] float scrollSensitivity = 1f;
[SerializeField] bool inertia = true;
[SerializeField] float decelerationRate = 0.03f;
[SerializeField]
Snap snap = new Snap
{
Enable = true,
VelocityThreshold = 0.5f,
Duration = 0.3f,
Easing = Ease.InOutCubic
};
[SerializeField] bool draggable = true;
[SerializeField] Scrollbar scrollbar = default;
public ScrollDirection ScrollDirection => scrollDirection;
public MovementType MovementType
{
get => movementType;
set => movementType = value;
}
public float ViewportSize => scrollDirection == ScrollDirection.Horizontal
? viewport.rect.size.x
: viewport.rect.size.y;
public bool SnapEnabled
{
get => snap.Enable;
set => snap.Enable = value;
}
public float ScrollSensitivity
{
get => scrollSensitivity;
set => scrollSensitivity = value;
}
public bool Draggable
{
get => draggable;
set => draggable = value;
}
public Scrollbar Scrollbar => scrollbar;
public float Position
{
get => currentPosition;
set
{
autoScrollState.Reset();
velocity = 0f;
dragging = false;
UpdatePosition(value);
}
}
readonly AutoScrollState autoScrollState = new AutoScrollState();
Action<float> onValueChanged;
Action<int> onSelectionChanged;
Vector2 beginDragPointerPosition;
float scrollStartPosition;
float prevPosition;
float currentPosition;
int totalCount;
bool dragging;
float velocity;
[Serializable]
class Snap
{
public bool Enable;
public float VelocityThreshold;
public float Duration;
public Ease Easing;
}
static readonly Func<float, float> DefaultEasingFunction = EasingFunction.Get(Ease.OutCubic);
class AutoScrollState
{
public bool Enable;
public bool Elastic;
public float Duration;
public Func<float, float> EasingFunction;
public float StartTime;
public float EndPosition;
public Action OnComplete;
public void Reset()
{
Enable = false;
Elastic = false;
Duration = 0f;
StartTime = 0f;
EasingFunction = DefaultEasingFunction;
EndPosition = 0f;
OnComplete = null;
}
public void Complete()
{
OnComplete?.Invoke();
Reset();
}
}
protected override void Start()
{
base.Start();
if (scrollbar)
{
scrollbar.onValueChanged.AddListener(x => UpdatePosition(x * (totalCount - 1f), false));
}
}
public void OnValueChanged(Action<float> callback) => onValueChanged = callback;
public void OnSelectionChanged(Action<int> callback) => onSelectionChanged = callback;
public void SetTotalCount(int totalCount) => this.totalCount = totalCount;
public void ScrollTo(float position, float duration, Action onComplete = null) => ScrollTo(position, duration, Ease.OutCubic, onComplete);
public void ScrollTo(float position, float duration, Ease easing, Action onComplete = null) => ScrollTo(position, duration, EasingFunction.Get(easing), onComplete);
public void ScrollTo(float position, float duration, Func<float, float> easingFunction, Action onComplete = null)
{
if (duration <= 0f)
{
Position = CircularPosition(position, totalCount);
onComplete?.Invoke();
return;
}
autoScrollState.Reset();
autoScrollState.Enable = true;
autoScrollState.Duration = duration;
autoScrollState.EasingFunction = easingFunction ?? DefaultEasingFunction;
autoScrollState.StartTime = Time.unscaledTime;
autoScrollState.EndPosition = currentPosition + CalculateMovementAmount(currentPosition, position);
autoScrollState.OnComplete = onComplete;
velocity = 0f;
scrollStartPosition = currentPosition;
UpdateSelection(Mathf.RoundToInt(CircularPosition(autoScrollState.EndPosition, totalCount)));
}
public void JumpTo(int index)
{
if (index < 0 || index > totalCount - 1)
{
throw new ArgumentOutOfRangeException(nameof(index));
}
autoScrollState.Reset();
velocity = 0f;
dragging = false;
UpdateSelection(index);
UpdatePosition(index);
}
public MovementDirection GetMovementDirection(int sourceIndex, int destIndex)
{
var movementAmount = CalculateMovementAmount(sourceIndex, destIndex);
return scrollDirection == ScrollDirection.Horizontal
? movementAmount > 0
? MovementDirection.Left
: MovementDirection.Right
: movementAmount > 0
? MovementDirection.Up
: MovementDirection.Down;
}
void IBeginDragHandler.OnBeginDrag(PointerEventData eventData)
{
if (!draggable || eventData.button != PointerEventData.InputButton.Left)
{
return;
}
RectTransformUtility.ScreenPointToLocalPointInRectangle(
viewport,
eventData.position,
eventData.pressEventCamera,
out beginDragPointerPosition);
scrollStartPosition = currentPosition;
dragging = true;
autoScrollState.Reset();
}
void IDragHandler.OnDrag(PointerEventData eventData)
{
if (!draggable || eventData.button != PointerEventData.InputButton.Left || !dragging)
{
return;
}
if (!RectTransformUtility.ScreenPointToLocalPointInRectangle(
viewport,
eventData.position,
eventData.pressEventCamera,
out var dragPointerPosition))
{
return;
}
var pointerDelta = dragPointerPosition - beginDragPointerPosition;
var position = (scrollDirection == ScrollDirection.Horizontal ? -pointerDelta.x : pointerDelta.y)
/ ViewportSize
* scrollSensitivity
+ scrollStartPosition;
var offset = CalculateOffset(position);
position += offset;
if (movementType == MovementType.Elastic)
{
if (offset != 0f)
{
position -= RubberDelta(offset, scrollSensitivity);
}
}
UpdatePosition(position);
}
void IEndDragHandler.OnEndDrag(PointerEventData eventData)
{
if (!draggable || eventData.button != PointerEventData.InputButton.Left)
{
return;
}
dragging = false;
}
float CalculateOffset(float position)
{
if (movementType == MovementType.Unrestricted)
{
return 0f;
}
if (position < 0f)
{
return -position;
}
if (position > totalCount - 1)
{
return totalCount - 1 - position;
}
return 0f;
}
void UpdatePosition(float position, bool updateScrollbar = true)
{
onValueChanged?.Invoke(currentPosition = position);
if (scrollbar && updateScrollbar)
{
scrollbar.value = Mathf.Clamp01(position / Mathf.Max(totalCount - 1f, 1e-4f));
}
}
void UpdateSelection(int index) => onSelectionChanged?.Invoke(index);
float RubberDelta(float overStretching, float viewSize) =>
(1 - 1 / (Mathf.Abs(overStretching) * 0.55f / viewSize + 1)) * viewSize * Mathf.Sign(overStretching);
void Update()
{
var deltaTime = Time.unscaledDeltaTime;
var offset = CalculateOffset(currentPosition);
if (autoScrollState.Enable)
{
var position = 0f;
if (autoScrollState.Elastic)
{
position = Mathf.SmoothDamp(currentPosition, currentPosition + offset, ref velocity,
elasticity, Mathf.Infinity, deltaTime);
if (Mathf.Abs(velocity) < 0.01f)
{
position = Mathf.Clamp(Mathf.RoundToInt(position), 0, totalCount - 1);
velocity = 0f;
autoScrollState.Complete();
}
}
else
{
var alpha = Mathf.Clamp01((Time.unscaledTime - autoScrollState.StartTime) /
Mathf.Max(autoScrollState.Duration, float.Epsilon));
position = Mathf.LerpUnclamped(scrollStartPosition, autoScrollState.EndPosition,
autoScrollState.EasingFunction(alpha));
if (Mathf.Approximately(alpha, 1f))
{
autoScrollState.Complete();
}
}
UpdatePosition(position);
}
else if (!dragging && (!Mathf.Approximately(offset, 0f) || !Mathf.Approximately(velocity, 0f)))
{
var position = currentPosition;
if (movementType == MovementType.Elastic && !Mathf.Approximately(offset, 0f))
{
autoScrollState.Reset();
autoScrollState.Enable = true;
autoScrollState.Elastic = true;
UpdateSelection(Mathf.Clamp(Mathf.RoundToInt(position), 0, totalCount - 1));
}
else if (inertia)
{
velocity *= Mathf.Pow(decelerationRate, deltaTime);
if (Mathf.Abs(velocity) < 0.001f)
{
velocity = 0f;
}
position += velocity * deltaTime;
if (snap.Enable && Mathf.Abs(velocity) < snap.VelocityThreshold)
{
ScrollTo(Mathf.RoundToInt(currentPosition), snap.Duration, snap.Easing);
}
}
else
{
velocity = 0f;
}
if (!Mathf.Approximately(velocity, 0f))
{
if (movementType == MovementType.Clamped)
{
offset = CalculateOffset(position);
position += offset;
if (Mathf.Approximately(position, 0f) || Mathf.Approximately(position, totalCount - 1f))
{
velocity = 0f;
UpdateSelection(Mathf.RoundToInt(position));
}
}
UpdatePosition(position);
}
}
if (!autoScrollState.Enable && dragging && inertia)
{
var newVelocity = (currentPosition - prevPosition) / deltaTime;
velocity = Mathf.Lerp(velocity, newVelocity, deltaTime * 10f);
}
prevPosition = currentPosition;
}
float CalculateMovementAmount(float sourcePosition, float destPosition)
{
if (movementType != MovementType.Unrestricted)
{
return Mathf.Clamp(destPosition, 0, totalCount - 1) - sourcePosition;
}
var movementAmount = CircularPosition(destPosition, totalCount) - CircularPosition(sourcePosition, totalCount);
if (Mathf.Abs(movementAmount) > totalCount * 0.5f)
{
movementAmount = Mathf.Sign(-movementAmount) * (totalCount - Mathf.Abs(movementAmount));
}
return movementAmount;
}
float CircularPosition(float p, int size) => size < 1 ? 0 : p < 0 ? size - 1 + (p + 1) % size : p % size;
}
}