Feature: Add vertical scrolling support with Ctrl+Up/Down.

Author: deanthecoder

G33kShell.Desktop/Console/Views/ConsoleView.axaml.cs

@@ -143,22 +143,29 @@ public override void Render(DrawingContext context)
 
         // Draw the screen cursor.
         var cursor = m_windowManager.Cursor;
-        if (cursor?.IsVisible == true && cursor.X >= 0 && cursor.X < screen.Width && cursor.Y >= 0 && cursor.Y < screen.Height)
+        if (cursor?.IsVisible == true)
         {
-            var foregroundColor = m_windowManager.Skin.ForegroundColor;
-            if (cursor.IsBusy)
+            var cursorY = cursor.Y + m_windowManager.OffsetY;
+            if (cursorY >= 0 && cursorY < screen.Height)
             {
-                var animChars = "/-\\|";
-                var animFrame = (Environment.TickCount64 / 100) % animChars.Length;
-                DrawTextRun(context, new StringBuilder(animChars, (int)animFrame, 1, 1), cursor.X, cursor.Y, foregroundColor, screen.Chars[cursor.Y][cursor.X].Background);
-            }
-            else
-            {
-                var isFlashOn = (Environment.TickCount64 - cursor.MoveTime) % 1000 < 500;
-                if (isFlashOn)
+                if (cursor.X >= 0 && cursor.X < screen.Width)
                 {
-                    var cursorRect = new Rect(cursor.X * CharWidth + Padding.Left, cursor.Y * CharHeight + Padding.Top, CharWidth, CharHeight);
-                    context.FillRectangle(GetBrush(foregroundColor), cursorRect);
+                    var foregroundColor = m_windowManager.Skin.ForegroundColor;
+                    if (cursor.IsBusy)
+                    {
+                        var animChars = "/-\\|";
+                        var animFrame = (Environment.TickCount64 / 100) % animChars.Length;
+                        DrawTextRun(context, new StringBuilder(animChars, (int)animFrame, 1, 1), cursor.X, cursorY, foregroundColor, screen.Chars[cursorY][cursor.X].Background);
+                    }
+                    else
+                    {
+                        var isFlashOn = (Environment.TickCount64 - cursor.MoveTime) % 1000 < 500;
+                        if (isFlashOn)
+                        {
+                            var cursorRect = new Rect(cursor.X * CharWidth + Padding.Left, cursorY * CharHeight + Padding.Top, CharWidth, CharHeight);
+                            context.FillRectangle(GetBrush(foregroundColor), cursorRect);
+                        }
+                    }
                 }
             }
         }

G33kShell.Desktop/Console/WindowManager.cs

@@ -12,6 +12,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Avalonia.Input;
 using Avalonia.Layout;
 using DTC.Core;
 using G33kShell.Desktop.Console.Controls;
@@ -27,6 +28,7 @@ public class WindowManager
     private readonly List<ConsoleEvent> m_consoleEvents = new List<ConsoleEvent>();
     private SkinBase m_skin;
     private ConsoleCursor m_cursor;
+    internal int OffsetY { get; private set; }
 
     public Visual Root { get; }
 
@@ -86,7 +88,7 @@ public void Render()
                     visual.ActualX = pos.x;
                     visual.ActualY = pos.y;
                     using (visual.Screen.Lock(out var sourceScreen))
-                        sourceScreen.CopyTo(targetScreen, pos.x, pos.y);
+                        sourceScreen.CopyTo(targetScreen, pos.x, pos.y + OffsetY);
                 }
             }
         }
@@ -225,6 +227,31 @@ public void ProcessEvents()
             var visualTree = GetVisualTree(Root).ToArray();
             foreach (var consoleEvent in m_consoleEvents)
             {
+                if (consoleEvent is KeyConsoleEvent keyEvent && keyEvent.Direction == KeyConsoleEvent.KeyDirection.Down)
+                {
+                    if ((keyEvent.Modifiers & KeyModifiers.Control) != KeyModifiers.None)
+                    {
+                        switch (keyEvent.Key)
+                        {
+                            case Key.Up:
+                                OffsetY++;
+                                Root.InvalidateVisual();
+                                continue;
+                            case Key.Down:
+                                OffsetY--;
+                                Root.InvalidateVisual();
+                                continue;
+                        }
+                    }
+                    
+                    // Any other key resets scroll offset.
+                    if (OffsetY != 0 && keyEvent.Modifiers == KeyModifiers.None)
+                    {
+                        Root.InvalidateVisual();
+                        OffsetY = 0;
+                    }
+                }
+                
                 foreach (var visual in visualTree)
                 {
                     var handled = false;