Initial commit of TexturePacker.

Source/OpenTK/TexturePacker.cs

@@ -0,0 +1,196 @@
+#region --- License ---
+/* Copyright (c) 2006, 2007 Stefanos Apostolopoulos
+ * See license.txt for license info
+ */
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Drawing;
+using System.Drawing.Imaging;
+
+namespace OpenTK
+{
+    class TexturePacker<T> where T : IPackable<T>
+    {
+        Dictionary<T, Node> items = new Dictionary<T, Node>();
+        
+        Node root;
+
+        #region --- Constructors ---
+
+        public TexturePacker(int width, int height)
+        {
+            if (width <= 0)
+                throw new ArgumentOutOfRangeException("width", width, "Must be greater than zero.");
+            if (height <= 0)
+                throw new ArgumentOutOfRangeException("height", height, "Must be greater than zero.");
+
+            root = new Node();
+            root.Rect = new Rectangle(0, 0, width, width);
+        }
+
+        #endregion
+
+        #region public Rectangle Add(T item)
+
+        /// <summary>
+        /// Packs the given item into the free space of the TexturePacker.
+        /// </summary>
+        /// <param name="item">The item to pack.</param>
+        /// <returns>A System.Drawing.Rectangle containing the coordinates of the packed item.</returns>
+        /// <exception cref="InvalidOperationException">Occurs if the item is larger than the available TexturePacker area</exception>
+        /// <exception cref="ArgumentException">Occurs if the item already exists in the TexturePacker.</exception>
+        public Rectangle Add(T item)
+        {
+            if (item.Width > root.Rect.Width || item.Height > root.Rect.Height)
+                throw new InvalidOperationException("The item is too large for this TexturePacker");
+
+            Node node;
+            if (!items.ContainsKey(item))
+            {
+                node = root.Insert(item);
+
+                // Tree is full and insertion failed:
+                if (node == null)
+                    throw new InvalidOperationException("There is not enough space to add this item. Consider calling the Clear() method.");
+
+                items.Add(item, node);
+                return node.Rect;
+            }
+            throw new ArgumentException("The item already exists in the TexturePacker.", "item");
+        }
+
+        #endregion
+
+        #region public bool Find(T item, out Rectangle rect)
+
+        /// <summary>
+        /// Searches for the item given and returns its bounding rectangle if it exists.
+        /// </summary>
+        /// <param name="item">The item to search for.</param>
+        /// <param name="rect">The bounding box of the item, if the item exists.</param>
+        /// <returns>True if the item exists, false otherwise.</returns>
+        public bool Find(T item, out Rectangle rect)
+        {
+            Node node;
+            bool found = items.TryGetValue(item, out node);
+            rect = node.Rect;
+            return found;
+        }
+
+        #endregion
+
+        #region public void Clear()
+
+        /// <summary>
+        /// Discards all packed items.
+        /// </summary>
+        public void Clear()
+        {
+            items.Clear();
+            root.Clear();
+        }
+
+        #endregion
+
+        #region Node
+
+        class Node
+        {
+            public Node()
+            {
+            }
+
+            Node left, right;
+            Rectangle rect;
+            int use_count;
+
+            public Rectangle Rect { get { return rect; } set { rect = value; } }
+            public Node Left { get { return left; } set { left = value; } }
+            public Node Right { get { return right; } set { right = value; } }
+
+            #region --- Constructor ---
+
+            public bool Leaf
+            {
+                get { return left == null && right == null; }
+            }
+
+            #endregion
+
+            #region public Node Insert(T item)
+
+            public Node Insert(T item)
+            {
+                if (!this.Leaf)
+                {
+                    // Recurse towards left child, and if that fails, towards the right.
+                    Node new_node = left.Insert(item);
+                    return new_node ?? right.Insert(item);
+                }
+                else
+                {
+                    // We have recursed to a leaf.
+
+                    // If it is not empty go back.
+                    if (use_count != 0)
+                        return null;
+
+                    // If this leaf is too small go back.
+                    if (rect.Width < item.Width || rect.Height < item.Height)
+                        return null;
+
+                    // If this leaf is the right size, insert here.
+                    if (rect.Width == item.Width && rect.Height == item.Height)
+                    {
+                        use_count = 1;
+                        return this;
+                    }
+
+                    // This leaf is too large, split it up. We'll decide which way to split
+                    // by checking the width and height difference between this rectangle and
+                    // out item's bounding box. If the width difference is larger, we'll split
+                    // horizontaly, else verticaly.
+                    left = new Node();
+                    right = new Node();
+
+                    int dw = this.rect.Width - item.Width;
+                    int dh = this.rect.Height - item.Height;
+
+                    if (dw > dh)
+                    {
+                        left.rect = new Rectangle(rect.Left, rect.Top, item.Width, rect.Height);
+                        right.rect = new Rectangle(rect.Left + item.Width, rect.Top, rect.Width - item.Width, rect.Height);
+                    }
+                    else
+                    {
+                        left.rect = new Rectangle(rect.Left, rect.Top, rect.Width, item.Height);
+                        right.rect = new Rectangle(rect.Left, rect.Top + item.Height, rect.Width, rect.Height - item.Height);
+                    }
+
+                    return left.Insert(item);
+                }
+            }
+
+            #endregion
+
+            #region public void Clear()
+            
+            public void Clear()
+            {
+                if (left != null)
+                    left.Clear();
+                if (right != null)
+                    right.Clear();
+
+                left = right = null;
+            }
+
+            #endregion
+        }
+
+        #endregion
+    }
+}