/******************************************************************************
 * Copyright (C) Ultraleap, Inc. 2011-2021.                                   *
 *                                                                            *
 * Use subject to the terms of the Apache License 2.0 available at            *
 * http://www.apache.org/licenses/LICENSE-2.0, or another agreement           *
 * between Ultraleap and you, your company or other organization.             *
 ******************************************************************************/

using System;

namespace Leap.Unity.Animation
{

    /// <summary>
    /// Implement this interface to add your own interpolators to Tween!
    /// </summary>
    public interface IInterpolator : IPoolable, IDisposable
    {

        /// <summary>
        /// Called to trigger the interpolation of this interpolator.  Use
        /// this callback to do whatever work your interpolator needs to do.
        /// </summary>
        void Interpolate(float percent);

        /// <summary>
        /// Returns the 'length' of this interpolator, in whatever units
        /// make sense for this interpolator.  If you are interpolating 
        /// from one point to another, you would return the distance 
        /// between the points.
        /// 
        /// The only current use of this function is to drive the
        /// Tween.AtRate function.
        /// </summary>
        float length { get; }

        /// <summary>
        /// Returns whether or not this interpolator is currently considered
        /// valid.  Any invalid interpolators will be removed from a tween.
        /// </summary>
        bool isValid { get; }
    }
}