Feature: Add ClockCanvas screensaver with bouncing digital clock display.

Author: deanthecoder

G33kShell.Desktop/Console/HighResScreen.cs

@@ -34,10 +34,13 @@ public HighResScreen(ScreenData screen, DrawMode drawMode = DrawMode.Overwrite)
         m_screen = screen;
         m_drawMode = drawMode;
     }
-    
+
+    public int Width => m_screen.Width;
+    public int Height => m_screen.Height * 2;
+
     public void Plot(int x, int y, Rgb color)
     {
-        if (x < 0 || x >= m_screen.Width || y < 0 || y >= m_screen.Height * 2)
+        if (x < 0 || x >= Width || y < 0 || y >= Height)
             return; // Off screen.
 
         var isTopPixel = (y & 1) == 0;

G33kShell.Desktop/Console/Screensavers/ClockCanvas.cs

@@ -0,0 +1,117 @@
+// Code authored by Dean Edis (DeanTheCoder).
+// Anyone is free to copy, modify, use, compile, or distribute this software,
+// either in source code form or as a compiled binary, for any non-commercial
+//  purpose.
+// 
+// If you modify the code, please retain this copyright header,
+// and consider contributing back to the repository or letting us know
+// about your modifications. Your contributions are valued!
+// 
+// THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND.
+
+using System;
+using System.Diagnostics;
+using System.Linq;
+using System.Reflection;
+using DTC.Core.Extensions;
+using G33kShell.Desktop.Console.Controls;
+using JetBrains.Annotations;
+using WenceyWang.FIGlet;
+
+namespace G33kShell.Desktop.Console.Screensavers;
+
+/// <summary>
+/// Digital clock that bounces around the screen.
+/// </summary>
+[DebuggerDisplay("ClockCanvas:{X},{Y} {Width}x{Height}")]
+[UsedImplicitly]
+public class ClockCanvas : ScreensaverBase
+{
+    private readonly FIGletFont m_font;
+    private int m_posX;
+    private int m_posY;
+    private int m_dX = 1;
+    private int m_dY = 1;
+
+    public ClockCanvas(int screenWidth, int screenHeight) : base(screenWidth, screenHeight, 5)
+    {
+        Name = "clock";
+
+        m_font = LoadFont();
+    }
+
+    public override void UpdateFrame(ScreenData screen)
+    {
+        screen.Clear(Foreground, Background);
+        var highResScreen = new HighResScreen(screen);
+        
+        var now = DateTime.Now.ToString("HH:mm");
+        
+        // Calculate width and height of the text.
+        var textWidth = 0;
+        var textHeight = 0;
+        foreach (var ch in now)
+        {
+            var charLines = Enumerable.Range(0, m_font.Height)
+                .Select(y => m_font.GetCharacter(ch, y))
+                .ToArray();
+            if (charLines.Length > 0)
+                textWidth += charLines[0].Length;
+            
+            var blankLines = charLines
+                .Reverse()
+                .TakeWhile(string.IsNullOrWhiteSpace)
+                .Count();
+            textHeight = Math.Max(textHeight, m_font.Height - blankLines);
+        }
+
+        // Update position.
+        m_posX += m_dX;
+        m_posY += m_dY;
+
+        // Bounce off walls.
+        if (m_posX <= 0 || m_posX + textWidth >= highResScreen.Width)
+        {
+            m_dX = -m_dX;
+            m_posX = Math.Max(0, Math.Min(highResScreen.Width - textWidth, m_posX));
+        }
+        
+        if (m_posY <= 0 || m_posY + textHeight >= highResScreen.Height)
+        {
+            m_dY = -m_dY;
+            m_posY = Math.Max(0, Math.Min(highResScreen.Height - textHeight, m_posY));
+        }
+
+        // Draw the time at the bouncing position
+        for (var y = 0; y < m_font.Height; y++)
+        {
+            var offset = 0;
+            foreach (var textRow in now.Select(ch => m_font.GetCharacter(ch, y)))
+            {
+                for (var x = 0; x < textRow.Length; x++)
+                {
+                    var ch = textRow[x];
+                    if (ch == ' ')
+                        continue; // Nothing to draw.
+
+                    var screenX = m_posX + x + offset;
+                    var screenY = m_posY + y;
+                    highResScreen.Plot(screenX, screenY, ch == '█' ? Foreground : 0.25.Lerp(Background, Foreground));
+                }
+                
+                offset += textRow.Length;
+            }
+        }
+    }
+    
+    private static FIGletFont LoadFont()
+    {
+        // Enumerate all Avalonia embedded resources.
+        var fontFolder = Assembly.GetExecutingAssembly().GetDirectory();
+        var fontFile = fontFolder.GetFiles("Assets/Fonts/Figlet/*.flf").Single();
+
+        // Load the font.
+        using var fontStream = fontFile.OpenRead();
+        return new FIGletFont(fontStream);
+    }
+}