ZForge.Controls.TreeViewAdv.Tree.TreeViewAdv.CreateDragBitmap C# (CSharp) Метод

        private void CreateDragBitmap(IDataObject data)
        {
            if (UseColumns || !DisplayDraggingNodes)
                return;

            TreeNodeAdv[] nodes = data.GetData(typeof(TreeNodeAdv[])) as TreeNodeAdv[];
            if (nodes != null && nodes.Length > 0)
            {
                Rectangle rect = DisplayRectangle;
                Bitmap bitmap = new Bitmap(rect.Width, rect.Height);
                using (Graphics gr = Graphics.FromImage(bitmap))
                {
                    gr.Clear(BackColor);
                    DrawContext context = new DrawContext();
                    context.Graphics = gr;
                    context.Font = Font;
                    context.Enabled = true;
                    int y = 0;
                    int maxWidth = 0;
                    foreach (TreeNodeAdv node in nodes)
                    {
                        if (node.Tree == this)
                        {
                            int x = 0;
                            int height = _rowLayout.GetRowBounds(node.Row).Height;
                            foreach (NodeControl c in NodeControls)
                            {
                                Size s = c.GetActualSize(node, context);
                                if (!s.IsEmpty)
                                {
                                    int width = s.Width;
                                    rect = new Rectangle(x, y, width, height);
                                    x += (width + 1);
                                    context.Bounds = rect;
                                    c.Draw(node, context);
                                }
                            }
                            y += height;
                            maxWidth = Math.Max(maxWidth, x);
                        }
                    }

                    if (maxWidth > 0 && y > 0)
                    {
                        _dragBitmap = new Bitmap(maxWidth, y, PixelFormat.Format32bppArgb);
                        using (Graphics tgr = Graphics.FromImage(_dragBitmap))
                            tgr.DrawImage(bitmap, Point.Empty);
                        BitmapHelper.SetAlphaChanelValue(_dragBitmap, 150);
                    }
                    else
                        _dragBitmap = null;
                }
            }
        }