Update with corrections - 2

src/UglyToad.PdfPig/DocumentLayoutAnalysis/XYNode.cs

@@ -0,0 +1,130 @@
+using System.Collections.Generic;
+using System.Linq;
+using UglyToad.PdfPig.Geometry;
+using UglyToad.PdfPig.Util;
+
+namespace UglyToad.PdfPig.DocumentLayoutAnalysis
+{
+    /// <summary>
+    /// A Node used in the <see cref="RecursiveXYCut"/> algorithm.
+    /// </summary>
+    public class XYNode
+    {
+        /// <summary>
+        /// Returns true if this node is a leaf, false otherwise.
+        /// </summary>
+        public virtual bool IsLeaf => false;
+
+        /// <summary>
+        /// The rectangle completely containing the node.
+        /// </summary>
+        public PdfRectangle BoundingBox { get; set; }
+
+        /// <summary>
+        /// The children of the node.
+        /// </summary>
+        public XYNode[] Children { get; set; }
+
+        /// <summary>
+        /// Recursively counts the words included in this node.
+        /// </summary>
+        public virtual int CountWords()
+        {
+            if (Children == null) return 0;
+            int count = 0;
+            RecursiveCount(Children, ref count);
+            return count;
+        }
+
+        /// <summary>
+        /// Recursively gets the leafs (last nodes) of this node.
+        /// </summary>
+        public virtual List<XYLeaf> GetLeafs()
+        {
+            List<XYLeaf> leafs = new List<XYLeaf>();
+            if (Children == null || Children.Count() == 0) return leafs;
+            int level = 0;
+            RecursiveGetLeafs(Children, ref leafs, level);
+            return leafs;
+        }
+
+        /// <summary>
+        /// Create a new <see cref="XYNode"/>.
+        /// </summary>
+        /// <param name="children">The node's children.</param>
+        public XYNode(params XYNode[] children)
+            : this(children?.ToList())
+        {
+
+        }
+
+        /// <summary>
+        /// Create a new <see cref="XYNode"/>.
+        /// </summary>
+        /// <param name="children">The node's children.</param>
+        public XYNode(IEnumerable<XYNode> children)
+        {
+            if (children != null && children.Count() != 0)
+            {
+                Children = children.ToArray();
+                decimal left = children.Min(b => b.BoundingBox.Left);
+                decimal right = children.Max(b => b.BoundingBox.Right);
+                decimal bottom = children.Min(b => b.BoundingBox.Bottom);
+                decimal top = children.Max(b => b.BoundingBox.Top);
+                BoundingBox = new PdfRectangle(left, bottom, right, top);
+            }
+            else
+            {
+                Children = EmptyArray<XYNode>.Instance;
+            }
+        }
+
+        private void RecursiveCount(IEnumerable<XYNode> children, ref int count)
+        {
+            if (children.Count() == 0) return;
+            foreach (XYNode node in children.Where(x => x.IsLeaf))
+            {
+                count += node.CountWords();
+            }
+
+            foreach (XYNode node in children.Where(x => !x.IsLeaf))
+            {
+                RecursiveCount(node.Children, ref count);
+            }
+        }
+
+        private void RecursiveGetLeafs(IEnumerable<XYNode> children, ref List<XYLeaf> leafs, int level)
+        {
+            if (children.Count() == 0) return;
+            bool isVerticalCut = level % 2 == 0;
+
+            foreach (XYLeaf node in children.Where(x => x.IsLeaf))
+            {
+                leafs.Add(node);
+            }
+
+            level++;
+
+            IEnumerable<XYNode> notLeafs = children.Where(x => !x.IsLeaf);
+
+            if (isVerticalCut)
+            {
+                notLeafs = notLeafs.OrderBy(x => x.BoundingBox.Left).ToList();
+            }
+            else
+            {
+                notLeafs = notLeafs.OrderByDescending(x => x.BoundingBox.Top).ToList();
+            }
+
+            foreach (XYNode node in notLeafs)
+            {
+                RecursiveGetLeafs(node.Children, ref leafs, level);
+            }
+        }
+
+        public override string ToString()
+        {
+            return (IsLeaf ? "Leaf" : "Node");
+        }
+    }
+}