greenshot/Greenshot/Memento/ChangeFieldHolderMemento.cs

77 lines
2.3 KiB
C#

/*
* Greenshot - a free and open source screenshot tool
* Copyright (C) 2007-2021 Thomas Braun, Jens Klingen, Robin Krom
*
* For more information see: http://getgreenshot.org/
* The Greenshot project is hosted on GitHub https://github.com/greenshot/greenshot
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 1 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
using GreenshotPlugin.Interfaces.Drawing;
namespace Greenshot.Memento
{
/// <summary>
/// The ChangeFieldHolderMemento makes it possible to undo-redo an IDrawableContainer move
/// </summary>
public class ChangeFieldHolderMemento : IMemento
{
private IDrawableContainer _drawableContainer;
private readonly IField _fieldToBeChanged;
private readonly object _oldValue;
public ChangeFieldHolderMemento(IDrawableContainer drawableContainer, IField fieldToBeChanged)
{
_drawableContainer = drawableContainer;
_fieldToBeChanged = fieldToBeChanged;
_oldValue = fieldToBeChanged.Value;
}
public void Dispose()
{
Dispose(true);
}
protected virtual void Dispose(bool disposing)
{
if (disposing)
{
_drawableContainer?.Dispose();
}
_drawableContainer = null;
}
public bool Merge(IMemento otherMemento)
{
if (otherMemento is not ChangeFieldHolderMemento other) return false;
if (!other._drawableContainer.Equals(_drawableContainer)) return false;
return other._fieldToBeChanged.Equals(_fieldToBeChanged);
}
public IMemento Restore()
{
// Before
_drawableContainer.Invalidate();
ChangeFieldHolderMemento oldState = new ChangeFieldHolderMemento(_drawableContainer, _fieldToBeChanged);
_fieldToBeChanged.Value = _oldValue;
// After
_drawableContainer.Invalidate();
return oldState;
}
}
}