Colourisation

README.md

@@ -36,7 +36,8 @@
    var sizer = new LogSizer(wordCloud);
    using var engine = new SkGraphicEngine(sizer, wordCloud);
    var layout = new SpiralLayout(wordCloud);
-   var wcg = new WordCloudGenerator<SKBitmap>(wordCloud, engine, layout);
+   var colorizer = new RandomColorizer();    
+   var wcg = new WordCloudGenerator<SKBitmap>(wordCloud, engine, layout, colorizer);
    ```
 
 5. Now we can *arrange* the topic cloud:

examples/WordFrequency.ConsoleApp/Program.cs

@@ -31,6 +31,7 @@ static int Main(string[] args)
                 // Process words on input.
                 var freqs = new Dictionary<string, int>();
                 var whitespaces = new Regex(@"\s+");
+
                 while (Console.ReadLine() is string line)
                 {
                     foreach (var word in whitespaces.Split(line))
@@ -55,7 +56,8 @@ static int Main(string[] args)
                 var sizer = new LogSizer(wordCloud);
                 using var engine = new SkGraphicEngine(sizer, wordCloud);
                 var layout = new SpiralLayout(wordCloud);
-                var wcg = new WordCloudGenerator<SKBitmap>(wordCloud, engine, layout);
+                var colorizer = new RandomColorizer();   //new DefaultColorizer(); uses default color set in WordCloudInput 
+                var wcg = new WordCloudGenerator<SKBitmap>(wordCloud, engine, layout, colorizer);
 
                 // Draw the bitmap on white background.
                 using var final = new SKBitmap(wordCloud.Width, wordCloud.Height);

src/KnowledgePicker.WordCloud/Drawing/DefaultColorizer.cs

@@ -0,0 +1,17 @@
+namespace KnowledgePicker.WordCloud.Drawing
+{
+    /// <summary>
+    /// Gets the default color set in the WordCloudInput
+    /// </summary>
+    public class DefaultColorizer : IColorizer
+    {
+        /// <summary>
+        /// Gets the hex string color for text
+        /// </summary>
+        /// <returns>Hex string color</returns>
+        public string GetColorAsHex()
+        {
+            return WordCloudInput.DefaultTextColor;
+        }
+    }
+}

src/KnowledgePicker.WordCloud/Drawing/IColorizer.cs

@@ -0,0 +1,7 @@
+namespace KnowledgePicker.WordCloud.Drawing
+{
+    public interface IColorizer
+    {
+        string GetColorAsHex();
+    }
+}

src/KnowledgePicker.WordCloud/Drawing/IGraphicEngine.cs

@@ -26,10 +26,14 @@ public interface IGraphicEngine : IDisposable
         /// Draws <paramref name="text"/> with weight proportional to
         /// <paramref name="count"/>.
         /// </summary>
+        /// <param name="location"></param>
         /// <param name="measured">
         /// Result of <see cref="Measure(string, int)"/>.
         /// </param>
-        void Draw(PointD location, RectangleD measured, string text, int count);
+        /// <param name="text"></param>
+        /// <param name="count"></param>
+        /// <param name="randomColorHex"></param>
+        void Draw(PointD location, RectangleD measured, string text, int count, string randomColorHex);
     }
 
     public interface IGraphicEngine<TBitmap> : IGraphicEngine

src/KnowledgePicker.WordCloud/Drawing/RandomColorizer.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Drawing;
+
+namespace KnowledgePicker.WordCloud.Drawing
+{
+    /// <summary>
+    /// Allows random colors for the word cloud text
+    /// </summary>
+    public class RandomColorizer : IColorizer
+    {
+        /// <summary>
+        /// Used to select random colors.
+        /// </summary>
+        private Random Random { get; set; } = new Random(Environment.TickCount);
+
+        /// <summary>
+        /// Gets a random color.
+        /// </summary>
+        /// <returns>Color</returns>
+        private Color GetRandomColor()
+        {
+#pragma warning disable CA5394 // Do not use insecure randomness
+            return Color.FromArgb(Random.Next(0, 255), Random.Next(0, 255), Random.Next(0, 255));
+#pragma warning restore CA5394 // Do not use insecure randomness
+        }
+
+        /// <summary>
+        /// Converts Color to Hext string
+        /// </summary>
+        /// <returns>Color</returns>
+        private static string ConvertToHexString(Color c)
+        {
+            return $"#{c.R:X2}{c.G:X2}{c.B:X2}";
+        }
+
+        /// <summary>
+        /// Gets the randon RGB color and
+        /// returns a hex string
+        /// </summary>
+        /// <returns>Hexstring</returns>
+        public string GetColorAsHex()
+        {
+            Color c = GetRandomColor();
+            return ConvertToHexString(c);
+        }
+
+    }
+}

src/KnowledgePicker.WordCloud/Drawing/SkGraphicEngine.cs

@@ -40,11 +40,12 @@ public RectangleD Measure(string text, int count)
             return new RectangleD(rect.Left + m, rect.Top + m, rect.Width + 2 * m, rect.Height + 2 * m);
         }
 
-        public void Draw(PointD location, RectangleD measured, string text, int count)
+        public void Draw(PointD location, RectangleD measured, string text, int count, string? randomColorHex)
         {
             // For computation explanation, see
             // https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/graphics/skiasharp/basics/text.
             textPaint.TextSize = (float)Sizer.GetFontSize(count);
+            textPaint.Color = SKColor.Parse(randomColorHex);
             canvas.DrawText(text, (float)(location.X - measured.Left),
                 (float)(location.Y - measured.Top), textPaint);
         }

src/KnowledgePicker.WordCloud/WordCloudGenerator.cs

@@ -23,13 +23,15 @@ public class WordCloudGenerator<TBitmap>
         private readonly WordCloudInput wordCloud;
         private readonly IGraphicEngine<TBitmap> engine;
         private readonly ILayout layout;
+        private readonly IColorizer colorizer;
 
         public WordCloudGenerator(WordCloudInput wordCloud,
-            IGraphicEngine<TBitmap> engine, ILayout layout)
+            IGraphicEngine<TBitmap> engine, ILayout layout, IColorizer colorizer)
         {
             this.wordCloud = wordCloud;
             this.engine = engine;
             this.layout = layout;
+            this.colorizer = colorizer;
         }
 
         private T Process<T>(
@@ -59,12 +61,12 @@ private T Process<T>(
         /// cref="IGraphicEngine{TBitmap}.Bitmap"/>.
         /// </summary>
         public TBitmap Draw()
-        {
+        {       
             return Process((engine, items) =>
             {
                 // Draw words.
                 foreach (var item in items)
-                    engine.Draw(item.Location, item.Measured, item.Entry.Word, item.Entry.Count);
+                    engine.Draw(item.Location, item.Measured, item.Entry.Word, item.Entry.Count, colorizer.GetColorAsHex());
                 return engine.Bitmap;
             });
         }