// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
 
using System.Diagnostics;
 
namespace System.Windows.Input.Manipulations
{
    /// <summary>
    /// Represents data that is sent with a
    /// <strong><see cref="System.Windows.Input.Manipulations.ManipulationProcessor2D.Delta">ManipulationProcessor2D.Delta</see></strong> 
    /// event or an
    /// <strong><see cref="System.Windows.Input.Manipulations.InertiaProcessor2D.Delta">InertiaProcessor2D.Delta</see></strong> 
    /// event.
    /// </summary>
    public class Manipulation2DDeltaEventArgs: EventArgs
    {
        private readonly float originX;
        private readonly float originY;
        private readonly ManipulationVelocities2D velocities;
        private readonly ManipulationDelta2D delta;
        private readonly ManipulationDelta2D cumulative;
 
        /// <summary>
        /// Creates a new Manipulation2DDeltaEventArgs object with
        /// the specified properties.
        /// </summary>
        /// <param name="originX">the x coordinate of the composite position of the manipulation</param>
        /// <param name="originY">the y coordinate of the composite position of the manipulation</param>
        /// <param name="velocities">velocities</param>
        /// <param name="delta">amount of change for this delta</param>
        /// <param name="cumulative">total change since operation began</param>
        internal Manipulation2DDeltaEventArgs(
            float originX,
            float originY,
            ManipulationVelocities2D velocities,
            ManipulationDelta2D delta,
            ManipulationDelta2D cumulative)
        {
            Debug.Assert(Validations.IsFinite(originX), "originX should be finite");
            Debug.Assert(Validations.IsFinite(originY), "originY should be finite");
            Debug.Assert(velocities != null, "velocities should not be null");
            Debug.Assert(delta != null, "delta should not be null");
            Debug.Assert(cumulative != null, "cumulative should not be null");
            this.originX = originX;
            this.originY = originY;
            this.velocities = velocities;
            this.delta = delta;
            this.cumulative = cumulative;
        }
 
        /// <summary>
        /// Gets the new x-coordinate of the composite position of the manipulation.
        /// </summary>
        /// <remarks>
        /// The origin point represented by the <strong>OriginX</strong> and
        /// <strong><see cref="OriginY"/></strong>
        /// properties is the average position of all manipulators associated with an element. 
        /// </remarks>
        public float OriginX
        {
            get
            {
                return this.originX;
            }
        }
 
        /// <summary>
        /// Gets the new y-coordinate of the composite position of the manipulation.
        /// </summary>
        /// <remarks>
        /// The origin point represented by the <strong><see cref="OriginX"/></strong> and
        /// <strong>OriginY</strong>
        /// properties is the average position of all manipulators associated with an element. 
        /// </remarks>
        public float OriginY
        {
            get
            {
                return this.originY;
            }
        }
 
        /// <summary>
        /// Gets the current velocities of the manipulation.
        /// </summary>
        public ManipulationVelocities2D Velocities
        {
            get
            {
                return this.velocities;
            }
        }
 
        /// <summary>
        /// Gets the amount of change since the last event.
        /// </summary>
        public ManipulationDelta2D Delta
        {
            get
            {
                return this.delta;
            }
        }
 
        /// <summary>
        /// Gets the total amount of change since the manipulation started.
        /// </summary>
        public ManipulationDelta2D Cumulative
        {
            get
            {
                return this.cumulative;
            }
        }
    }
}