Add project files.

AlientAttack.MonoGame/View/ViewTransform.cs

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+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Content;
+using Microsoft.Xna.Framework.Graphics;
+
+namespace AlienAttack.MonoGame.View;
+
+public class ViewTransform(Game game, GraphicsDeviceManager graphics)
+{
+    public readonly GameWindow Window = game.Window;
+    public readonly ContentManager Content = game.Content;
+    public readonly GraphicsDeviceManager Graphics = graphics;
+    public readonly GraphicsDevice GraphicsDevice = game.GraphicsDevice;
+    public readonly SpriteBatch SpriteBatch;
+
+    public float ScaleX => (float)WindowWidth / Graphics.PreferredBackBufferWidth;
+    public float ScaleY => (float)WindowHeight / Graphics.PreferredBackBufferHeight;
+    public float ScaleMin => MathHelper.Min(ScaleX, ScaleY);
+
+    public float OffsetX => KeepAspectRatio ? MathHelper.Max(ScaleX - ScaleY, 0) * ScreenWidth : 0;
+    public float OffsetY => KeepAspectRatio ? MathHelper.Max(ScaleY - ScaleX, 0) * ScreenHeight : 0;
+
+    public bool KeepAspectRatio = true;
+
+    public int ScreenWidth
+    {
+        get
+        {
+            return Graphics.PreferredBackBufferWidth;
+        }
+    }
+
+    public int ScreenHeight
+    {
+        get
+        {
+            return Graphics.PreferredBackBufferHeight;
+        }
+    }
+
+    public int WindowWidth
+    {
+        get
+        {
+            return Window.ClientBounds.Width;
+        }
+    }
+
+    public int WindowHeight
+    {
+        get
+        {
+            return Window.ClientBounds.Height;
+        }
+    }
+
+    public Matrix ViewMatrix
+    {
+        get
+        {
+            if (KeepAspectRatio)
+            {
+                return Matrix.CreateScale(ScaleMin, ScaleMin, 1.0f) * Matrix.CreateTranslation(OffsetX / 2, OffsetY / 2, 0);
+            }
+            else
+            {
+                return Matrix.CreateScale(ScaleX, ScaleY, 1.0f);
+            }
+        }
+    }
+}