greenshot/Greenshot/Memento/DrawableContainerBoundsChangeMemento.cs

/*
 * 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 Greenshot.Drawing;
using GreenshotPlugin.Core;
using System.Collections.Generic;
using System.Drawing;
using GreenshotPlugin.Interfaces.Drawing;

namespace Greenshot.Memento
{
	/// <summary>
	/// The DrawableContainerBoundsChangeMemento makes it possible to undo-redo an IDrawableContainer resize & move
	/// </summary>
	public class DrawableContainerBoundsChangeMemento : IMemento
	{
		private readonly List<Point> _points = new();
		private readonly List<Size> _sizes = new();
		private IDrawableContainerList _listOfdrawableContainer;

		private void StoreBounds()
		{
			foreach (IDrawableContainer drawableContainer in _listOfdrawableContainer)
			{
				_points.Add(drawableContainer.Location);
				_sizes.Add(drawableContainer.Size);
			}
		}

		public DrawableContainerBoundsChangeMemento(IDrawableContainerList listOfdrawableContainer)
		{
			_listOfdrawableContainer = listOfdrawableContainer;
			StoreBounds();
		}

		public DrawableContainerBoundsChangeMemento(IDrawableContainer drawableContainer)
		{
			_listOfdrawableContainer = new DrawableContainerList
			{
				drawableContainer
			};
			_listOfdrawableContainer.Parent = drawableContainer.Parent;
			StoreBounds();
		}

		public void Dispose()
		{
			Dispose(true);
		}

		protected virtual void Dispose(bool disposing)
		{
			if (disposing)
			{
				_listOfdrawableContainer?.Dispose();
			}
			_listOfdrawableContainer = null;
		}

		public bool Merge(IMemento otherMemento)
		{
			if (otherMemento is not DrawableContainerBoundsChangeMemento other) return false;
			
			if (ObjectExtensions.CompareLists(_listOfdrawableContainer, other._listOfdrawableContainer))
            {
	            // Lists are equal, as we have the state already we can ignore the new memento
	            return true;
            }
            return false;
		}

		public IMemento Restore()
		{
			var oldState = new DrawableContainerBoundsChangeMemento(_listOfdrawableContainer);
			for (int index = 0; index < _listOfdrawableContainer.Count; index++)
			{
				IDrawableContainer drawableContainer = _listOfdrawableContainer[index];
				// Before
				drawableContainer.Invalidate();
				drawableContainer.Left = _points[index].X;
				drawableContainer.Top = _points[index].Y;
				drawableContainer.Width = _sizes[index].Width;
				drawableContainer.Height = _sizes[index].Height;
				// After
				drawableContainer.Invalidate();
				drawableContainer.Parent.Modified = true;
			}
			return oldState;
		}
	}
}