AGE, Another Graphic Engine in .NET

/////////////////////////////////////////////////////////////////////////////////
// NeoDataType Another Graphic Engine
// --------------------
// Project Copyright (C)    : Fabio Zanetta, email: support@neodatatype.net
// Portions Copyright (C)   : Microsoft Corporation. All Rights Reserved.
// License                  : docs/license.txt
// ------------------------------------------------------------------------------
// File created by          : Fabio Zanetta, email: support@neodatatype.net
// ------------------------------------------------------------------------------
// Please, if you modify some parts of this file mark them as described in
// docs/modify_guidelines.txt
/////////////////////////////////////////////////////////////////////////////////

using System;
using System.Drawing;
using System.Collections.Generic;
using NeoDataType.Documents;

namespace NeoDataType.Graphic
{

    #region GraphicLayer

    [SaveThisClass()]
    public class GraphicLayer : DocumentGroup
    {

        bool _visible = true;
        GraphicItemCollection _items = new GraphicItemCollection();
        bool _refreshItemsCache = true;

        internal void RequireRefreshItemList()
        {
            _refreshItemsCache = true;
        }


        [SaveThisProperty]
        public bool Visible
        {
            get { return _visible; }
            set
            {
                _visible = value;
                PropertyChanged();
            }
        }

        protected void PropertyChanged()
        {
            if (Document != null)
            {
                ((GraphicDocument)Document).NotifyPropertyChanged(this);
            }
        }

        /// <summary>
        /// Collection of GraphicItem in the layer
        /// </summary>
        public GraphicItemCollection GraphicItems
        {
            get
            {

                if (_refreshItemsCache)
                {
                    _items.Clear();

                    foreach (DocumentItem di in Items)
                    {
                        if (di is GraphicItem)
                        {
                            _items.Add((GraphicItem)di);
                        }
                    }

                    _refreshItemsCache = false;
                }

                return _items;
            }
        }

        /// <summary>
        /// Save the GraphicDocument as an image file.
        /// </summary>
        public Image GetImage()
        {
            Rectangle docBounds = ((GraphicDocument)Document).GetBounds();          
            Bitmap bmp;
            if (!docBounds.IsEmpty)
            {
                bmp = new Bitmap(docBounds.Width, docBounds.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
                Graphics g = Graphics.FromImage(bmp);

                SolidBrush back = new SolidBrush(Color.White);
                g.FillRectangle(back, 0, 0, docBounds.Width, docBounds.Height);
                g.TranslateTransform(-docBounds.X, -docBounds.Y);
                foreach (GraphicItem item in GraphicItems)
                    if (item.Visible)
                        item.Painter.PaintItem(g);
                back.Dispose();
                g.Dispose();
            }
            else
            {
                bmp = new Bitmap(1, 1, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
            }
            return bmp;
        }

        /// <summary>
        /// Shift the group down in the group list.
        /// </summary>
        public void MoveDown()
        {
            if (Document != null)
            {
                int i = Document.GroupsInternal.IndexOf(this);
                if (i < Document.GroupsInternal.Count - 1)
                {
                    Document.GroupsInternal.Move(this, i + 1);
                    DocumentActionEventArgs e = new DocumentActionEventArgs(Document, this, null);
                    OnMoved(e);
                }
            }
        }

        /// <summary>
        /// Shift the group up in the group list.
        /// </summary>
        public void MoveUp()
        {
            if (Document != null)
            {
                int i = Document.GroupsInternal.IndexOf(this);
                if (i > 0)
                {
                    Document.GroupsInternal.Move(this, i - 1);
                    DocumentActionEventArgs e = new DocumentActionEventArgs(Document, this, null);
                    OnMoved(e);
                }
            }
        }

        
        public override void OnItemAdded(DocumentActionEventArgs e)
        {
            base.OnItemAdded(e);
            _refreshItemsCache = true;
            PropertyChanged();
        }

        public override void OnItemRemoved(DocumentActionEventArgs e)
        {
            base.OnItemRemoved(e);
            _refreshItemsCache = true;
            PropertyChanged();
        }

        protected override void OnMoved(DocumentActionEventArgs e)
        {
            base.OnMoved(e);
            ((GraphicDocument)Document).RequireRefreshLayerList();
            PropertyChanged();
        }
    }
    #endregion

}