Added some comments

Assets/Code/Editor/SlickViewLayout.cs

@@ -21,28 +21,34 @@ public SlickViewLayout(int totalRows, int rowHeight, Action<Rect, int, bool> dra
         }
 
 
-        public bool Draw(Rect rect, int totalRows, GUIStyle style)
+        /// <summary>
+        /// Draw
+        /// Called during the OnGUI of the client code
+        /// for SlickView to render its view
+        /// </summary>
+        /// <param name="rect"></param>
+        /// <param name="totalRows"></param>
+        /// <param name="style"></param>
+        public void Draw(Rect rect, int totalRows, GUIStyle style)
         {
             Event e = Event.current;
 
-            bool selectionChanged = false;
             _slickViewState.visRect   = rect;
             _slickViewState.totalRows = totalRows;
 
+            // iterate through all the rows that are _visible_ in the view 
+            // and call the draw delegate
             foreach (SlickViewElement el in SlickView.ListView(_slickViewState, style))
             {
                 if (e.type == EventType.MouseDown && e.button == 0 && el.position.Contains(e.mousePosition))
                 {
-                    _selectedRow     = _slickViewState.row;
-                    selectionChanged = true;
+                    _selectedRow = _slickViewState.row;
                 }
                 else if (e.type == EventType.Repaint)
                 {
                     _draw(el.position, el.row, _selectedRow == el.row);
                 }
             }
-
-            return selectionChanged;
         }
     }
 }

Assets/Code/Editor/SlickViewWindow.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using UnityEditor;
 using UnityEngine;
@@ -9,17 +10,20 @@ public class SlickViewWindow : EditorWindow
         private SlickViewLayout _slickViewLayout;
 
         private static SlickViewWindow _instance;
-        public static  GUIStyle        Box;
-        public static  GUIStyle        EvenBackground;
-        public static  GUIStyle        OddBackground;
-        public static  GUIStyle        LogStyle;
+        private static GUIStyle        Box;
+        private static GUIStyle        EvenBackground;
+        private static GUIStyle        OddBackground;
+        private static GUIStyle        LogStyle;
         private        bool            _initialisedGUIStyles;
         Texture2D[]                    _textures;
         private Vector2                _scrollPos;
         private bool                   _slickview = true;
         private Rect[]                 _columnRects;
         GUIContent                     _tempContent = new GUIContent();
 
+        /// <summary>
+        /// An example list view element for the demo window
+        /// </summary>
         public struct ExampleListElement
         {
             public ExampleListElement(int index, Texture2D texture2D)
@@ -28,19 +32,21 @@ public ExampleListElement(int index, Texture2D texture2D)
                 name          = texture2D.name;
                 width         = texture2D.width;
                 height        = texture2D.height;
+                format        = texture2D.format;
                 texture       = texture2D;
-                columnWidth   = new[] {60, 240, 60, 60, 50};
+                columnWidth   = new[] {60, 240, 60, 60, 100, 21};
             }
 
-            public string    elementNumber;
-            public string    name;
-            public int       width;
-            public int       height;
-            public Texture2D texture;
-            public int[]     columnWidth;
+            public string        elementNumber;
+            public string        name;
+            public int           width;
+            public int           height;
+            public TextureFormat format;
+            public Texture2D     texture;
+            public int[]         columnWidth;
         }
 
-        private List<ExampleListElement> _listElements = new List<ExampleListElement>(1000);
+        private List<ExampleListElement> _listElements = new List<ExampleListElement>(10000);
 
         [MenuItem("SlickView/Open Demo Window", false, 0)]
         public static void CreateDeviceWindow()
@@ -55,7 +61,11 @@ static void AfterAssembliesLoaded()
             _instance.InitVars();
         }
 
-        void Init()
+        /// <summary>
+        /// InitStyles
+        /// This has to be called from OnGUI rather than a initialisation step
+        /// </summary>
+        void InitStyles()
         {
             if (!_initialisedGUIStyles)
             {
@@ -67,11 +77,21 @@ void Init()
             }
         }
 
+        /// <summary>
+        /// InitVars
+        /// Set up all the elements for the demo window
+        /// This happens whenever the window is opened or the assemblies have been loaded
+        /// </summary>
         void InitVars()
         {
             _listElements.Clear();
-            _slickViewLayout = new SlickViewLayout(32, 24, DrawElement);
-            _textures        = Resources.FindObjectsOfTypeAll<Texture2D>();
+
+            // create the slick view class and give it a starting size and delegate for drawing each element
+            _slickViewLayout = new SlickViewLayout(32, 21, DrawElement);
+
+            // the demo window finds all the textures in the project and displays them in order
+            // over and over until it reaches the specified capacity
+            _textures = Resources.FindObjectsOfTypeAll<Texture2D>();
             for (int i = 0; i < _listElements.Capacity; i++)
             {
                 _listElements.Add(new ExampleListElement(i, _textures[i % _textures.Length]));
@@ -82,37 +102,70 @@ void InitVars()
 
         private void OnEnable()
         {
-            position              = new Rect(200, 200, 300, 400);
-            wantsLessLayoutEvents = true;
-            titleContent          = new GUIContent("SlickView");
+            position = new Rect(200, 200, 300, 400);
+            //   wantsLessLayoutEvents = true;
+            titleContent = new GUIContent("SlickView");
             InitVars();
         }
 
         private void OnGUI()
         {
-            Init();
+            InitStyles();
 
             _slickViewLayout.Draw(position, _listElements.Capacity, Box);
+
+            // uncomment this to compare performance with SlickView
+            // ExistingScrollView();
         }
 
+        /// <summary>
+        /// ExistingScrollView
+        /// Example implementation using the existing ScrollView
+        /// </summary>
+        void OldScrollView()
+        {
+            _scrollPos = EditorGUILayout.BeginScrollView(_scrollPos);
+            foreach (var el in _listElements)
+            {
+                EditorGUILayout.TextField(el.name);
+                EditorGUILayout.IntField(el.width);
+            }
+
+            EditorGUILayout.EndScrollView();
+        }
 
+
+        /// <summary>
+        /// DrawElement
+        /// Called for each row that is visible
+        /// </summary>
+        /// <param name="rect"></param>
+        /// Area in which to render the elements
+        /// <param name="row"></param>
+        /// Row number in the underlying list
+        /// <param name="selected"></param>
+        /// Is this row currently selected by the user
         void DrawElement(Rect rect, int row, bool selected)
         {
             ExampleListElement el = _listElements[row];
             GUIStyle           s  = (row & 1) == 0 ? OddBackground : EvenBackground;
             s.Draw(rect, false, false, selected, false);
             int column = 0;
-            DrawLabel(ref rect, el.elementNumber, el.columnWidth[column++], false);
-            DrawLabel(ref rect, el.name, el.columnWidth[column++], false);
+
+            // draw some info using the row number as an index into the underlying element array
+            DrawLabel(ref rect, el.elementNumber, el.columnWidth[column++], selected);
+            DrawLabel(ref rect, el.name, el.columnWidth[column++], selected);
             DrawInt(ref rect, el.width, el.columnWidth[column++]);
             DrawInt(ref rect, el.height, el.columnWidth[column++]);
+            DrawEnum(ref rect, el.format, el.columnWidth[column++]);
             DrawTexture(ref rect, el.texture, el.columnWidth[column]);
         }
 
+        /// Some helper functions for displaying different types 
         void DrawInt(ref Rect r, int value, int width)
         {
             r.width = width;
-            EditorGUI.IntField(r, width);
+            EditorGUI.IntField(r, value);
             r.x += width;
         }
 
@@ -127,7 +180,14 @@ void DrawLabel(ref Rect r, string value, int width, bool selected)
         void DrawTexture(ref Rect r, Texture2D value, int width)
         {
             r.width = width;
-            EditorGUI.ObjectField(r, value, typeof(Texture2D), false);
+            EditorGUI.DrawPreviewTexture(r, value);
+            r.x += width;
+        }
+
+        void DrawEnum(ref Rect r, Enum value, int width)
+        {
+            r.width = width;
+            EditorGUI.EnumPopup(r, value);
             r.x += width;
         }
     }

README.md

@@ -68,3 +68,4 @@ Instead of iterating over the entire list of elements Slick view calculates whic
 |:--:| 
 | *Screenshot of the demo window in SlickView with 10,000 textures* |
 
+To bring up this demo window select Slick View -> Open Demo Window