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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
//
//
using System.ComponentModel;
using System.Windows.Input.Manipulations;
namespace System.Windows.Input
{
/// <summary>
/// Provides information about the start of the inertia phase of the manipulation.
/// </summary>
public sealed class ManipulationInertiaStartingEventArgs : InputEventArgs
{
/// <summary>
/// Instantiates a new instance of this class.
/// </summary>
internal ManipulationInertiaStartingEventArgs(
ManipulationDevice manipulationDevice,
int timestamp,
IInputElement manipulationContainer,
Point origin,
ManipulationVelocities initialVelocities,
bool isInInertia)
: base(manipulationDevice, timestamp)
{
ArgumentNullException.ThrowIfNull(initialVelocities);
RoutedEvent = Manipulation.ManipulationInertiaStartingEvent;
ManipulationContainer = manipulationContainer;
ManipulationOrigin = origin;
InitialVelocities = initialVelocities;
_isInInertia = isInInertia;
}
/// <summary>
/// Invokes a handler of this event.
/// </summary>
protected override void InvokeEventHandler(Delegate genericHandler, object genericTarget)
{
ArgumentNullException.ThrowIfNull(genericHandler);
ArgumentNullException.ThrowIfNull(genericTarget);
if (RoutedEvent == Manipulation.ManipulationInertiaStartingEvent)
{
((EventHandler<ManipulationInertiaStartingEventArgs>)genericHandler)(genericTarget, this);
}
else
{
base.InvokeEventHandler(genericHandler, genericTarget);
}
}
/// <summary>
/// Defines the coordinate space of the other properties.
/// </summary>
public IInputElement ManipulationContainer
{
get;
private set;
}
/// <summary>
/// Returns the value of the origin.
/// </summary>
public Point ManipulationOrigin
{
get;
set;
}
/// <summary>
/// Returns the default, calculated velocities of the current manipulation.
/// </summary>
/// <remarks>
/// These values can be used to populate the initial velocity properties in
/// the various behaviors that can be set.
/// </remarks>
public ManipulationVelocities InitialVelocities
{
get;
private set;
}
/// <summary>
/// The desired behavior for how position changes due to inertia.
/// </summary>
public InertiaTranslationBehavior TranslationBehavior
{
get
{
if (!IsBehaviorSet(Behaviors.Translation))
{
_translationBehavior = new InertiaTranslationBehavior(InitialVelocities.LinearVelocity);
SetBehavior(Behaviors.Translation);
}
return _translationBehavior;
}
set
{
_translationBehavior = value;
}
}
/// <summary>
/// The desired behavior for how the angle changes due to inertia.
/// </summary>
public InertiaRotationBehavior RotationBehavior
{
get
{
if (!IsBehaviorSet(Behaviors.Rotation))
{
_rotationBehavior = new InertiaRotationBehavior(InitialVelocities.AngularVelocity);
SetBehavior(Behaviors.Rotation);
}
return _rotationBehavior;
}
set
{
_rotationBehavior = value;
}
}
/// <summary>
/// The desired behavior for how the size changes due to inertia.
/// </summary>
public InertiaExpansionBehavior ExpansionBehavior
{
get
{
if (!IsBehaviorSet(Behaviors.Expansion))
{
_expansionBehavior = new InertiaExpansionBehavior(InitialVelocities.ExpansionVelocity);
SetBehavior(Behaviors.Expansion);
}
return _expansionBehavior;
}
set
{
_expansionBehavior = value;
}
}
/// <summary>
/// Method to cancel the Manipulation
/// </summary>
/// <returns>A bool indicating the success of Cancel</returns>
public bool Cancel()
{
if (!_isInInertia)
{
RequestedCancel = true;
return true;
}
return false;
}
/// <summary>
/// A handler Requested to cancel the Manipulation
/// </summary>
internal bool RequestedCancel
{
get;
private set;
}
/// <summary>
/// The Manipulators for this manipulation.
/// </summary>
public IEnumerable<IManipulator> Manipulators
{
get
{
if (_manipulators == null)
{
_manipulators = ((ManipulationDevice)Device).GetManipulatorsReadOnly();
}
return _manipulators;
}
}
/// <summary>
/// Supplies additional parameters for calculating the inertia.
/// </summary>
/// <param name="parameter">The new parameter.</param>
[Browsable(false)]
public void SetInertiaParameter(InertiaParameters2D parameter)
{
ArgumentNullException.ThrowIfNull(parameter);
if (_inertiaParameters == null)
{
_inertiaParameters = new List<InertiaParameters2D>();
}
_inertiaParameters.Add(parameter);
}
internal bool CanBeginInertia()
{
if (_inertiaParameters != null && _inertiaParameters.Count > 0)
{
return true;
}
if (_translationBehavior != null && _translationBehavior.CanUseForInertia())
{
return true;
}
if (_rotationBehavior != null && _rotationBehavior.CanUseForInertia())
{
return true;
}
if (_expansionBehavior != null && _expansionBehavior.CanUseForInertia())
{
return true;
}
return false;
}
internal void ApplyParameters(InertiaProcessor2D processor)
{
processor.InitialOriginX = (float)ManipulationOrigin.X;
processor.InitialOriginY = (float)ManipulationOrigin.Y;
ManipulationVelocities velocities = InitialVelocities;
InertiaTranslationBehavior.ApplyParameters(_translationBehavior, processor, velocities.LinearVelocity);
InertiaRotationBehavior.ApplyParameters(_rotationBehavior, processor, velocities.AngularVelocity);
InertiaExpansionBehavior.ApplyParameters(_expansionBehavior, processor, velocities.ExpansionVelocity);
if (_inertiaParameters != null)
{
for (int i = 0, count = _inertiaParameters.Count; i < count; i++)
{
processor.SetParameters(_inertiaParameters[i]);
}
}
}
private bool IsBehaviorSet(Behaviors behavior)
{
return ((_behaviors & behavior) == behavior);
}
private void SetBehavior(Behaviors behavior)
{
_behaviors |= behavior;
}
private List<InertiaParameters2D> _inertiaParameters;
private InertiaTranslationBehavior _translationBehavior;
private InertiaRotationBehavior _rotationBehavior;
private InertiaExpansionBehavior _expansionBehavior;
private Behaviors _behaviors = Behaviors.None;
private bool _isInInertia = false; // This is true when it is a second level inertia (inertia due to inertia).
private IEnumerable<IManipulator> _manipulators;
[Flags]
private enum Behaviors
{
None = 0,
Translation = 0x00000001,
Rotation = 0x00000002,
Expansion = 0x00000004
}
}
}
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