Implement grid size toggling matching stable

osu.Game.Rulesets.Osu/Edit/OsuRectangularPositionSnapGrid.cs

@@ -0,0 +1,50 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using osu.Framework.Input.Events;
+using osu.Game.Rulesets.Osu.UI;
+using osu.Game.Screens.Edit.Compose.Components;
+using osuTK;
+using osuTK.Input;
+
+namespace osu.Game.Rulesets.Osu.Edit
+{
+    public class OsuRectangularPositionSnapGrid : RectangularPositionSnapGrid
+    {
+        private static readonly int[] grid_sizes = { 4, 8, 16, 32 };
+
+        private int currentGridSizeIndex;
+
+        public OsuRectangularPositionSnapGrid(int gridSize)
+            : base(OsuPlayfield.BASE_SIZE / 2)
+        {
+            var gridSizeIndex = Array.IndexOf(grid_sizes, gridSize);
+            if (gridSizeIndex > 0)
+                currentGridSizeIndex = gridSizeIndex;
+            updateSpacing();
+        }
+
+        protected override bool OnKeyDown(KeyDownEvent e)
+        {
+            if (e.Key == Key.G)
+            {
+                nextGridSize();
+                return true;
+            }
+
+            return false;
+        }
+
+        private void nextGridSize()
+        {
+            currentGridSizeIndex = (currentGridSizeIndex + 1) % grid_sizes.Length;
+            updateSpacing();
+        }
+
+        private void updateSpacing()
+        {
+            Spacing = new Vector2(grid_sizes[currentGridSizeIndex]);
+        }
+    }
+}