Merge pull request #26311 from OliBomby/grids-3

Make editor flip, rotate, and scale tools revolve around the grid center

osu.Game.Rulesets.Osu.Tests/Editor/TestScenePreciseRotation.cs

@@ -116,7 +116,7 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
                 () => EditorBeatmap.HitObjects.OfType<HitCircle>().ElementAt(1).Position,
                 () => Is.EqualTo(OsuPlayfield.BASE_SIZE - new Vector2(200)));
 
-            AddStep("change rotation origin", () => getPopover().ChildrenOfType<EditorRadioButton>().ElementAt(1).TriggerClick());
+            AddStep("change rotation origin", () => getPopover().ChildrenOfType<EditorRadioButton>().ElementAt(2).TriggerClick());
             AddAssert("first object rotated 90deg around selection centre",
                 () => EditorBeatmap.HitObjects.OfType<HitCircle>().ElementAt(0).Position, () => Is.EqualTo(new Vector2(200, 200)));
             AddAssert("second object rotated 90deg around selection centre",

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

@@ -106,6 +106,7 @@ namespace osu.Game.Rulesets.Osu.Edit
                     {
                         RotationHandler = BlueprintContainer.SelectionHandler.RotationHandler,
                         ScaleHandler = (OsuSelectionScaleHandler)BlueprintContainer.SelectionHandler.ScaleHandler,
+                        GridToolbox = OsuGridToolboxGroup,
                     },
                     new GenerateToolboxGroup(),
                     FreehandSliderToolboxGroup

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

@@ -3,6 +3,7 @@
 
 using System.Collections.Generic;
 using System.Linq;
+using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Primitives;
 using osu.Framework.Graphics.UserInterface;
@@ -25,6 +26,9 @@ namespace osu.Game.Rulesets.Osu.Edit
 {
     public partial class OsuSelectionHandler : EditorSelectionHandler
     {
+        [Resolved]
+        private OsuGridToolboxGroup gridToolbox { get; set; } = null!;
+
         protected override void OnSelectionChanged()
         {
             base.OnSelectionChanged();
@@ -123,13 +127,43 @@ namespace osu.Game.Rulesets.Osu.Edit
         {
             var hitObjects = selectedMovableObjects;
 
-            var flipQuad = flipOverOrigin ? new Quad(0, 0, OsuPlayfield.BASE_SIZE.X, OsuPlayfield.BASE_SIZE.Y) : GeometryUtils.GetSurroundingQuad(hitObjects);
+            // If we're flipping over the origin, we take the grid origin position from the grid toolbox.
+            var flipQuad = flipOverOrigin ? new Quad(gridToolbox.StartPositionX.Value, gridToolbox.StartPositionY.Value, 0, 0) : GeometryUtils.GetSurroundingQuad(hitObjects);
+            Vector2 flipAxis = direction == Direction.Vertical ? Vector2.UnitY : Vector2.UnitX;
+
+            if (flipOverOrigin)
+            {
+                // If we're flipping over the origin, we take one of the axes of the grid.
+                // Take the axis closest to the direction we want to flip over.
+                switch (gridToolbox.GridType.Value)
+                {
+                    case PositionSnapGridType.Square:
+                        flipAxis = GeometryUtils.RotateVector(Vector2.UnitX, -((gridToolbox.GridLinesRotation.Value + 360 + 45) % 90 - 45));
+                        flipAxis = direction == Direction.Vertical ? flipAxis.PerpendicularLeft : flipAxis;
+                        break;
+
+                    case PositionSnapGridType.Triangle:
+                        // Hex grid has 3 axes, so you can not directly flip over one of the axes,
+                        // however it's still possible to achieve that flip by combining multiple flips over the other axes.
+                        // Angle degree range for vertical = (-120, -60]
+                        // Angle degree range for horizontal = [-30, 30)
+                        flipAxis = direction == Direction.Vertical
+                            ? GeometryUtils.RotateVector(Vector2.UnitX, -((gridToolbox.GridLinesRotation.Value + 360 + 30) % 60 + 60))
+                            : GeometryUtils.RotateVector(Vector2.UnitX, -((gridToolbox.GridLinesRotation.Value + 360) % 60 - 30));
+                        break;
+                }
+            }
+
+            var controlPointFlipQuad = new Quad();
 
             bool didFlip = false;
 
             foreach (var h in hitObjects)
             {
-                var flippedPosition = GeometryUtils.GetFlippedPosition(direction, flipQuad, h.Position);
+                var flippedPosition = GeometryUtils.GetFlippedPosition(flipAxis, flipQuad, h.Position);
+
+                // Clamp the flipped position inside the playfield bounds, because the flipped position might be outside the playfield bounds if the origin is not centered.
+                flippedPosition = Vector2.Clamp(flippedPosition, Vector2.Zero, OsuPlayfield.BASE_SIZE);
 
                 if (!Precision.AlmostEquals(flippedPosition, h.Position))
                 {
@@ -142,12 +176,7 @@ namespace osu.Game.Rulesets.Osu.Edit
                     didFlip = true;
 
                     foreach (var cp in slider.Path.ControlPoints)
-                    {
+                        cp.Position = GeometryUtils.GetFlippedPosition(flipAxis, controlPointFlipQuad, cp.Position);
-                        cp.Position = new Vector2(
-                            (direction == Direction.Horizontal ? -1 : 1) * cp.Position.X,
-                            (direction == Direction.Vertical ? -1 : 1) * cp.Position.Y
-                        );
-                    }
                 }
             }
 

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

@@ -69,6 +69,7 @@ namespace osu.Game.Rulesets.Osu.Edit
 
         private Dictionary<OsuHitObject, OriginalHitObjectState>? objectsInScale;
         private Vector2? defaultOrigin;
+        private List<Vector2>? originalConvexHull;
 
         public override void Begin()
         {
@@ -84,9 +85,12 @@ namespace osu.Game.Rulesets.Osu.Edit
                 ? GeometryUtils.GetSurroundingQuad(slider.Path.ControlPoints.Select(p => slider.Position + p.Position))
                 : GeometryUtils.GetSurroundingQuad(objectsInScale.Keys);
             defaultOrigin = OriginalSurroundingQuad.Value.Centre;
+            originalConvexHull = objectsInScale.Count == 1 && objectsInScale.First().Key is Slider slider2
+                ? GeometryUtils.GetConvexHull(slider2.Path.ControlPoints.Select(p => slider2.Position + p.Position))
+                : GeometryUtils.GetConvexHull(objectsInScale.Keys);
         }
 
-        public override void Update(Vector2 scale, Vector2? origin = null, Axes adjustAxis = Axes.Both)
+        public override void Update(Vector2 scale, Vector2? origin = null, Axes adjustAxis = Axes.Both, float axisRotation = 0)
         {
             if (!OperationInProgress.Value)
                 throw new InvalidOperationException($"Cannot {nameof(Update)} a scale operation without calling {nameof(Begin)} first!");
@@ -94,6 +98,7 @@ namespace osu.Game.Rulesets.Osu.Edit
             Debug.Assert(objectsInScale != null && defaultOrigin != null && OriginalSurroundingQuad != null);
 
             Vector2 actualOrigin = origin ?? defaultOrigin.Value;
+            scale = clampScaleToAdjustAxis(scale, adjustAxis);
 
             // for the time being, allow resizing of slider paths only if the slider is
             // the only hit object selected. with a group selection, it's likely the user
@@ -102,15 +107,15 @@ namespace osu.Game.Rulesets.Osu.Edit
             {
                 var originalInfo = objectsInScale[slider];
                 Debug.Assert(originalInfo.PathControlPointPositions != null && originalInfo.PathControlPointTypes != null);
-                scaleSlider(slider, scale, originalInfo.PathControlPointPositions, originalInfo.PathControlPointTypes);
+                scaleSlider(slider, scale, originalInfo.PathControlPointPositions, originalInfo.PathControlPointTypes, axisRotation);
             }
             else
             {
-                scale = ClampScaleToPlayfieldBounds(scale, actualOrigin);
+                scale = ClampScaleToPlayfieldBounds(scale, actualOrigin, adjustAxis, axisRotation);
 
                 foreach (var (ho, originalState) in objectsInScale)
                 {
-                    ho.Position = GeometryUtils.GetScaledPosition(scale, actualOrigin, originalState.Position);
+                    ho.Position = GeometryUtils.GetScaledPosition(scale, actualOrigin, originalState.Position, axisRotation);
                 }
             }
 
@@ -134,14 +139,34 @@ namespace osu.Game.Rulesets.Osu.Edit
         private IEnumerable<OsuHitObject> selectedMovableObjects => selectedItems.Cast<OsuHitObject>()
                                                                                  .Where(h => h is not Spinner);
 
-        private void scaleSlider(Slider slider, Vector2 scale, Vector2[] originalPathPositions, PathType?[] originalPathTypes)
+        private Vector2 clampScaleToAdjustAxis(Vector2 scale, Axes adjustAxis)
+        {
+            switch (adjustAxis)
+            {
+                case Axes.Y:
+                    scale.X = 1;
+                    break;
+
+                case Axes.X:
+                    scale.Y = 1;
+                    break;
+
+                case Axes.None:
+                    scale = Vector2.One;
+                    break;
+            }
+
+            return scale;
+        }
+
+        private void scaleSlider(Slider slider, Vector2 scale, Vector2[] originalPathPositions, PathType?[] originalPathTypes, float axisRotation = 0)
         {
             scale = Vector2.ComponentMax(scale, new Vector2(Precision.FLOAT_EPSILON));
 
             // Maintain the path types in case they were defaulted to bezier at some point during scaling
             for (int i = 0; i < slider.Path.ControlPoints.Count; i++)
             {
-                slider.Path.ControlPoints[i].Position = originalPathPositions[i] * scale;
+                slider.Path.ControlPoints[i].Position = GeometryUtils.GetScaledPosition(scale, Vector2.Zero, originalPathPositions[i], axisRotation);
                 slider.Path.ControlPoints[i].Type = originalPathTypes[i];
             }
 
@@ -176,11 +201,13 @@ namespace osu.Game.Rulesets.Osu.Edit
         /// </summary>
         /// <param name="origin">The origin from which the scale operation is performed</param>
         /// <param name="scale">The scale to be clamped</param>
+        /// <param name="adjustAxis">The axes to adjust the scale in.</param>
+        /// <param name="axisRotation">The rotation of the axes in degrees</param>
         /// <returns>The clamped scale vector</returns>
-        public Vector2 ClampScaleToPlayfieldBounds(Vector2 scale, Vector2? origin = null)
+        public Vector2 ClampScaleToPlayfieldBounds(Vector2 scale, Vector2? origin = null, Axes adjustAxis = Axes.Both, float axisRotation = 0)
         {
             //todo: this is not always correct for selections involving sliders. This approximation assumes each point is scaled independently, but sliderends move with the sliderhead.
-            if (objectsInScale == null)
+            if (objectsInScale == null || adjustAxis == Axes.None)
                 return scale;
 
             Debug.Assert(defaultOrigin != null && OriginalSurroundingQuad != null);
@@ -188,24 +215,60 @@ namespace osu.Game.Rulesets.Osu.Edit
             if (objectsInScale.Count == 1 && objectsInScale.First().Key is Slider slider)
                 origin = slider.Position;
 
+            float cos = MathF.Cos(float.DegreesToRadians(-axisRotation));
+            float sin = MathF.Sin(float.DegreesToRadians(-axisRotation));
+            scale = clampScaleToAdjustAxis(scale, adjustAxis);
             Vector2 actualOrigin = origin ?? defaultOrigin.Value;
+            IEnumerable<Vector2> points;
+
+            if (axisRotation == 0)
+            {
                 var selectionQuad = OriginalSurroundingQuad.Value;
+                points = new[]
+                {
+                    selectionQuad.TopLeft,
+                    selectionQuad.TopRight,
+                    selectionQuad.BottomLeft,
+                    selectionQuad.BottomRight
+                };
+            }
+            else
+                points = originalConvexHull!;
 
-            var tl1 = Vector2.Divide(-actualOrigin, selectionQuad.TopLeft - actualOrigin);
+            foreach (var point in points)
-            var tl2 = Vector2.Divide(OsuPlayfield.BASE_SIZE - actualOrigin, selectionQuad.TopLeft - actualOrigin);
+            {
-            var br1 = Vector2.Divide(-actualOrigin, selectionQuad.BottomRight - actualOrigin);
+                scale = clampToBound(scale, point, Vector2.Zero);
-            var br2 = Vector2.Divide(OsuPlayfield.BASE_SIZE - actualOrigin, selectionQuad.BottomRight - actualOrigin);
+                scale = clampToBound(scale, point, OsuPlayfield.BASE_SIZE);
-
+            }
-            if (!Precision.AlmostEquals(selectionQuad.TopLeft.X - actualOrigin.X, 0))
-                scale.X = selectionQuad.TopLeft.X - actualOrigin.X < 0 ? MathHelper.Clamp(scale.X, tl2.X, tl1.X) : MathHelper.Clamp(scale.X, tl1.X, tl2.X);
-            if (!Precision.AlmostEquals(selectionQuad.TopLeft.Y - actualOrigin.Y, 0))
-                scale.Y = selectionQuad.TopLeft.Y - actualOrigin.Y < 0 ? MathHelper.Clamp(scale.Y, tl2.Y, tl1.Y) : MathHelper.Clamp(scale.Y, tl1.Y, tl2.Y);
-            if (!Precision.AlmostEquals(selectionQuad.BottomRight.X - actualOrigin.X, 0))
-                scale.X = selectionQuad.BottomRight.X - actualOrigin.X < 0 ? MathHelper.Clamp(scale.X, br2.X, br1.X) : MathHelper.Clamp(scale.X, br1.X, br2.X);
-            if (!Precision.AlmostEquals(selectionQuad.BottomRight.Y - actualOrigin.Y, 0))
-                scale.Y = selectionQuad.BottomRight.Y - actualOrigin.Y < 0 ? MathHelper.Clamp(scale.Y, br2.Y, br1.Y) : MathHelper.Clamp(scale.Y, br1.Y, br2.Y);
 
             return Vector2.ComponentMax(scale, new Vector2(Precision.FLOAT_EPSILON));
+
+            float minPositiveComponent(Vector2 v) => MathF.Min(v.X < 0 ? float.PositiveInfinity : v.X, v.Y < 0 ? float.PositiveInfinity : v.Y);
+
+            Vector2 clampToBound(Vector2 s, Vector2 p, Vector2 bound)
+            {
+                p -= actualOrigin;
+                bound -= actualOrigin;
+                var a = new Vector2(cos * cos * p.X - sin * cos * p.Y, -sin * cos * p.X + sin * sin * p.Y);
+                var b = new Vector2(sin * sin * p.X + sin * cos * p.Y, sin * cos * p.X + cos * cos * p.Y);
+
+                switch (adjustAxis)
+                {
+                    case Axes.X:
+                        s.X = MathF.Min(scale.X, minPositiveComponent(Vector2.Divide(bound - b, a)));
+                        break;
+
+                    case Axes.Y:
+                        s.Y = MathF.Min(scale.Y, minPositiveComponent(Vector2.Divide(bound - a, b)));
+                        break;
+
+                    case Axes.Both:
+                        s = Vector2.ComponentMin(s, s * minPositiveComponent(Vector2.Divide(bound, a * s.X + b * s.Y)));
+                        break;
+                }
+
+                return s;
+            }
         }
 
         private void moveSelectionInBounds()

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

@@ -1,6 +1,7 @@
 // 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 System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
@@ -19,16 +20,19 @@ namespace osu.Game.Rulesets.Osu.Edit
     {
         private readonly SelectionRotationHandler rotationHandler;
 
-        private readonly Bindable<PreciseRotationInfo> rotationInfo = new Bindable<PreciseRotationInfo>(new PreciseRotationInfo(0, RotationOrigin.PlayfieldCentre));
+        private readonly OsuGridToolboxGroup gridToolbox;
+
+        private readonly Bindable<PreciseRotationInfo> rotationInfo = new Bindable<PreciseRotationInfo>(new PreciseRotationInfo(0, RotationOrigin.GridCentre));
 
         private SliderWithTextBoxInput<float> angleInput = null!;
         private EditorRadioButtonCollection rotationOrigin = null!;
 
         private RadioButton selectionCentreButton = null!;
 
-        public PreciseRotationPopover(SelectionRotationHandler rotationHandler)
+        public PreciseRotationPopover(SelectionRotationHandler rotationHandler, OsuGridToolboxGroup gridToolbox)
         {
             this.rotationHandler = rotationHandler;
+            this.gridToolbox = gridToolbox;
 
             AllowableAnchors = new[] { Anchor.CentreLeft, Anchor.CentreRight };
         }
@@ -58,6 +62,9 @@ namespace osu.Game.Rulesets.Osu.Edit
                         RelativeSizeAxes = Axes.X,
                         Items = new[]
                         {
+                            new RadioButton("Grid centre",
+                                () => rotationInfo.Value = rotationInfo.Value with { Origin = RotationOrigin.GridCentre },
+                                () => new SpriteIcon { Icon = FontAwesome.Regular.PlusSquare }),
                             new RadioButton("Playfield centre",
                                 () => rotationInfo.Value = rotationInfo.Value with { Origin = RotationOrigin.PlayfieldCentre },
                                 () => new SpriteIcon { Icon = FontAwesome.Regular.Square }),
@@ -93,10 +100,19 @@ namespace osu.Game.Rulesets.Osu.Edit
 
             rotationInfo.BindValueChanged(rotation =>
             {
-                rotationHandler.Update(rotation.NewValue.Degrees, rotation.NewValue.Origin == RotationOrigin.PlayfieldCentre ? OsuPlayfield.BASE_SIZE / 2 : null);
+                rotationHandler.Update(rotation.NewValue.Degrees, getOriginPosition(rotation.NewValue));
             });
         }
 
+        private Vector2? getOriginPosition(PreciseRotationInfo rotation) =>
+            rotation.Origin switch
+            {
+                RotationOrigin.GridCentre => gridToolbox.StartPosition.Value,
+                RotationOrigin.PlayfieldCentre => OsuPlayfield.BASE_SIZE / 2,
+                RotationOrigin.SelectionCentre => null,
+                _ => throw new ArgumentOutOfRangeException(nameof(rotation))
+            };
+
         protected override void PopIn()
         {
             base.PopIn();
@@ -114,6 +130,7 @@ namespace osu.Game.Rulesets.Osu.Edit
 
     public enum RotationOrigin
     {
+        GridCentre,
         PlayfieldCentre,
         SelectionCentre
     }

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

@@ -20,21 +20,25 @@ namespace osu.Game.Rulesets.Osu.Edit
     {
         private readonly OsuSelectionScaleHandler scaleHandler;
 
-        private readonly Bindable<PreciseScaleInfo> scaleInfo = new Bindable<PreciseScaleInfo>(new PreciseScaleInfo(1, ScaleOrigin.PlayfieldCentre, true, true));
+        private readonly OsuGridToolboxGroup gridToolbox;
+
+        private readonly Bindable<PreciseScaleInfo> scaleInfo = new Bindable<PreciseScaleInfo>(new PreciseScaleInfo(1, ScaleOrigin.GridCentre, true, true));
 
         private SliderWithTextBoxInput<float> scaleInput = null!;
         private BindableNumber<float> scaleInputBindable = null!;
         private EditorRadioButtonCollection scaleOrigin = null!;
 
+        private RadioButton gridCentreButton = null!;
         private RadioButton playfieldCentreButton = null!;
         private RadioButton selectionCentreButton = null!;
 
         private OsuCheckbox xCheckBox = null!;
         private OsuCheckbox yCheckBox = null!;
 
-        public PreciseScalePopover(OsuSelectionScaleHandler scaleHandler)
+        public PreciseScalePopover(OsuSelectionScaleHandler scaleHandler, OsuGridToolboxGroup gridToolbox)
         {
             this.scaleHandler = scaleHandler;
+            this.gridToolbox = gridToolbox;
 
             AllowableAnchors = new[] { Anchor.CentreLeft, Anchor.CentreRight };
         }
@@ -66,6 +70,9 @@ namespace osu.Game.Rulesets.Osu.Edit
                         RelativeSizeAxes = Axes.X,
                         Items = new[]
                         {
+                            gridCentreButton = new RadioButton("Grid centre",
+                                () => setOrigin(ScaleOrigin.GridCentre),
+                                () => new SpriteIcon { Icon = FontAwesome.Regular.PlusSquare }),
                             playfieldCentreButton = new RadioButton("Playfield centre",
                                 () => setOrigin(ScaleOrigin.PlayfieldCentre),
                                 () => new SpriteIcon { Icon = FontAwesome.Regular.Square }),
@@ -97,6 +104,10 @@ namespace osu.Game.Rulesets.Osu.Edit
                     },
                 }
             };
+            gridCentreButton.Selected.DisabledChanged += isDisabled =>
+            {
+                gridCentreButton.TooltipText = isDisabled ? "The current selection cannot be scaled relative to grid centre." : string.Empty;
+            };
             playfieldCentreButton.Selected.DisabledChanged += isDisabled =>
             {
                 playfieldCentreButton.TooltipText = isDisabled ? "The current selection cannot be scaled relative to playfield centre." : string.Empty;
@@ -123,19 +134,20 @@ namespace osu.Game.Rulesets.Osu.Edit
 
             selectionCentreButton.Selected.Disabled = !(scaleHandler.CanScaleX.Value || scaleHandler.CanScaleY.Value);
             playfieldCentreButton.Selected.Disabled = scaleHandler.IsScalingSlider.Value && !selectionCentreButton.Selected.Disabled;
+            gridCentreButton.Selected.Disabled = playfieldCentreButton.Selected.Disabled;
 
             scaleOrigin.Items.First(b => !b.Selected.Disabled).Select();
 
             scaleInfo.BindValueChanged(scale =>
             {
-                var newScale = new Vector2(scale.NewValue.XAxis ? scale.NewValue.Scale : 1, scale.NewValue.YAxis ? scale.NewValue.Scale : 1);
+                var newScale = new Vector2(scale.NewValue.Scale, scale.NewValue.Scale);
-                scaleHandler.Update(newScale, getOriginPosition(scale.NewValue));
+                scaleHandler.Update(newScale, getOriginPosition(scale.NewValue), getAdjustAxis(scale.NewValue), getRotation(scale.NewValue));
             });
         }
 
         private void updateAxisCheckBoxesEnabled()
         {
-            if (scaleInfo.Value.Origin == ScaleOrigin.PlayfieldCentre)
+            if (scaleInfo.Value.Origin != ScaleOrigin.SelectionCentre)
             {
                 toggleAxisAvailable(xCheckBox.Current, true);
                 toggleAxisAvailable(yCheckBox.Current, true);
@@ -162,7 +174,7 @@ namespace osu.Game.Rulesets.Osu.Edit
                 return;
 
             const float max_scale = 10;
-            var scale = scaleHandler.ClampScaleToPlayfieldBounds(new Vector2(max_scale), getOriginPosition(scaleInfo.Value));
+            var scale = scaleHandler.ClampScaleToPlayfieldBounds(new Vector2(max_scale), getOriginPosition(scaleInfo.Value), getAdjustAxis(scaleInfo.Value), getRotation(scaleInfo.Value));
 
             if (!scaleInfo.Value.XAxis)
                 scale.X = max_scale;
@@ -179,7 +191,18 @@ namespace osu.Game.Rulesets.Osu.Edit
             updateAxisCheckBoxesEnabled();
         }
 
-        private Vector2? getOriginPosition(PreciseScaleInfo scale) => scale.Origin == ScaleOrigin.PlayfieldCentre ? OsuPlayfield.BASE_SIZE / 2 : null;
+        private Vector2? getOriginPosition(PreciseScaleInfo scale) =>
+            scale.Origin switch
+            {
+                ScaleOrigin.GridCentre => gridToolbox.StartPosition.Value,
+                ScaleOrigin.PlayfieldCentre => OsuPlayfield.BASE_SIZE / 2,
+                ScaleOrigin.SelectionCentre => null,
+                _ => throw new ArgumentOutOfRangeException(nameof(scale))
+            };
+
+        private Axes getAdjustAxis(PreciseScaleInfo scale) => scale.XAxis ? scale.YAxis ? Axes.Both : Axes.X : Axes.Y;
+
+        private float getRotation(PreciseScaleInfo scale) => scale.Origin == ScaleOrigin.GridCentre ? gridToolbox.GridLinesRotation.Value : 0;
 
         private void setAxis(bool x, bool y)
         {
@@ -204,6 +227,7 @@ namespace osu.Game.Rulesets.Osu.Edit
 
     public enum ScaleOrigin
     {
+        GridCentre,
         PlayfieldCentre,
         SelectionCentre
     }

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

@@ -27,6 +27,8 @@ namespace osu.Game.Rulesets.Osu.Edit
         public SelectionRotationHandler RotationHandler { get; init; } = null!;
         public OsuSelectionScaleHandler ScaleHandler { get; init; } = null!;
 
+        public OsuGridToolboxGroup GridToolbox { get; init; } = null!;
+
         public TransformToolboxGroup()
             : base("transform")
         {
@@ -44,10 +46,10 @@ namespace osu.Game.Rulesets.Osu.Edit
                 {
                     rotateButton = new EditorToolButton("Rotate",
                         () => new SpriteIcon { Icon = FontAwesome.Solid.Undo },
-                        () => new PreciseRotationPopover(RotationHandler)),
+                        () => new PreciseRotationPopover(RotationHandler, GridToolbox)),
                     scaleButton = new EditorToolButton("Scale",
                         () => new SpriteIcon { Icon = FontAwesome.Solid.ArrowsAlt },
-                        () => new PreciseScalePopover(ScaleHandler))
+                        () => new PreciseScalePopover(ScaleHandler, GridToolbox))
                 }
             };
         }

osu.Game.Tests/Utils/GeometryUtilsTest.cs

@@ -0,0 +1,33 @@
+// 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 NUnit.Framework;
+using osu.Game.Utils;
+using osuTK;
+
+namespace osu.Game.Tests.Utils
+{
+    [TestFixture]
+    public class GeometryUtilsTest
+    {
+        [TestCase(new int[] { }, new int[] { })]
+        [TestCase(new[] { 0, 0 }, new[] { 0, 0 })]
+        [TestCase(new[] { 0, 0, 1, 1, 1, -1, 2, 0 }, new[] { 0, 0, 1, 1, 2, 0, 1, -1 })]
+        [TestCase(new[] { 0, 0, 1, 1, 1, -1, 2, 0, 1, 0 }, new[] { 0, 0, 1, 1, 2, 0, 1, -1 })]
+        [TestCase(new[] { 0, 0, 1, 1, 2, -1, 2, 0, 1, 0, 4, 10 }, new[] { 0, 0, 4, 10, 2, -1 })]
+        public void TestConvexHull(int[] values, int[] expected)
+        {
+            var points = new Vector2[values.Length / 2];
+            for (int i = 0; i < values.Length; i += 2)
+                points[i / 2] = new Vector2(values[i], values[i + 1]);
+
+            var expectedPoints = new Vector2[expected.Length / 2];
+            for (int i = 0; i < expected.Length; i += 2)
+                expectedPoints[i / 2] = new Vector2(expected[i], expected[i + 1]);
+
+            var hull = GeometryUtils.GetConvexHull(points);
+
+            Assert.That(hull, Is.EquivalentTo(expectedPoints));
+        }
+    }
+}

osu.Game.Tests/Visual/Editing/TestSceneComposeSelectBox.cs

@@ -134,7 +134,7 @@ namespace osu.Game.Tests.Visual.Editing
                 OriginalSurroundingQuad = new Quad(targetContainer!.X, targetContainer.Y, targetContainer.Width, targetContainer.Height);
             }
 
-            public override void Update(Vector2 scale, Vector2? origin = null, Axes adjustAxis = Axes.Both)
+            public override void Update(Vector2 scale, Vector2? origin = null, Axes adjustAxis = Axes.Both, float axisRotation = 0)
             {
                 if (targetContainer == null)
                     throw new InvalidOperationException($"Cannot {nameof(Update)} a scale operation without calling {nameof(Begin)} first!");

osu.Game/Overlays/SkinEditor/SkinSelectionScaleHandler.cs

@@ -73,7 +73,7 @@ namespace osu.Game.Overlays.SkinEditor
             isFlippedY = false;
         }
 
-        public override void Update(Vector2 scale, Vector2? origin = null, Axes adjustAxis = Axes.Both)
+        public override void Update(Vector2 scale, Vector2? origin = null, Axes adjustAxis = Axes.Both, float axisRotation = 0)
         {
             if (objectsInScale == null)
                 throw new InvalidOperationException($"Cannot {nameof(Update)} a scale operation without calling {nameof(Begin)} first!");

osu.Game/Screens/Edit/Compose/Components/SelectionScaleHandler.cs

@@ -52,10 +52,11 @@ namespace osu.Game.Screens.Edit.Compose.Components
         /// If the default <see langword="null"/> value is supplied, a sane implementation-defined default will be used.
         /// </param>
         /// <param name="adjustAxis">The axes to adjust the scale in.</param>
-        public void ScaleSelection(Vector2 scale, Vector2? origin = null, Axes adjustAxis = Axes.Both)
+        /// <param name="axisRotation">The rotation of the axes in degrees.</param>
+        public void ScaleSelection(Vector2 scale, Vector2? origin = null, Axes adjustAxis = Axes.Both, float axisRotation = 0)
         {
             Begin();
-            Update(scale, origin, adjustAxis);
+            Update(scale, origin, adjustAxis, axisRotation);
             Commit();
         }
 
@@ -91,7 +92,8 @@ namespace osu.Game.Screens.Edit.Compose.Components
         /// If the default <see langword="null"/> value is supplied, a sane implementation-defined default will be used.
         /// </param>
         /// <param name="adjustAxis">The axes to adjust the scale in.</param>
-        public virtual void Update(Vector2 scale, Vector2? origin = null, Axes adjustAxis = Axes.Both)
+        /// <param name="axisRotation">The rotation of the axes in degrees.</param>
+        public virtual void Update(Vector2 scale, Vector2? origin = null, Axes adjustAxis = Axes.Both, float axisRotation = 0)
         {
         }
 

osu.Game/Utils/GeometryUtils.cs

@@ -51,6 +51,9 @@ namespace osu.Game.Utils
         /// Given a flip direction, a surrounding quad for all selected objects, and a position,
         /// will return the flipped position in screen space coordinates.
         /// </summary>
+        /// <param name="direction">The direction to flip towards.</param>
+        /// <param name="quad">The quad surrounding all selected objects. The center of this determines the position of the axis.</param>
+        /// <param name="position">The position to flip.</param>
         public static Vector2 GetFlippedPosition(Direction direction, Quad quad, Vector2 position)
         {
             var centre = quad.Centre;
@@ -69,6 +72,20 @@ namespace osu.Game.Utils
             return position;
         }
 
+        /// <summary>
+        /// Given a flip axis vector, a surrounding quad for all selected objects, and a position,
+        /// will return the flipped position in screen space coordinates.
+        /// </summary>
+        /// <param name="axis">The vector indicating the direction to flip towards. This is perpendicular to the mirroring axis.</param>
+        /// <param name="quad">The quad surrounding all selected objects. The center of this determines the position of the axis.</param>
+        /// <param name="position">The position to flip.</param>
+        public static Vector2 GetFlippedPosition(Vector2 axis, Quad quad, Vector2 position)
+        {
+            var centre = quad.Centre;
+
+            return position - 2 * Vector2.Dot(position - centre, axis) * axis;
+        }
+
         /// <summary>
         /// Given a scale vector, a surrounding quad for all selected objects, and a position,
         /// will return the scaled position in screen space coordinates.
@@ -93,9 +110,9 @@ namespace osu.Game.Utils
         /// Given a scale multiplier, an origin, and a position,
         /// will return the scaled position in screen space coordinates.
         /// </summary>
-        public static Vector2 GetScaledPosition(Vector2 scale, Vector2 origin, Vector2 position)
+        public static Vector2 GetScaledPosition(Vector2 scale, Vector2 origin, Vector2 position, float axisRotation = 0)
         {
-            return origin + (position - origin) * scale;
+            return origin + RotateVector(RotateVector(position - origin, axisRotation) * scale, -axisRotation);
         }
 
         /// <summary>
@@ -127,7 +144,67 @@ namespace osu.Game.Utils
         /// </summary>
         /// <param name="hitObjects">The hit objects to calculate a quad for.</param>
         public static Quad GetSurroundingQuad(IEnumerable<IHasPosition> hitObjects) =>
-            GetSurroundingQuad(hitObjects.SelectMany(h =>
+            GetSurroundingQuad(enumerateStartAndEndPositions(hitObjects));
+
+        /// <summary>
+        /// Returns the points that make up the convex hull of the provided points.
+        /// </summary>
+        /// <param name="points">The points to calculate a convex hull.</param>
+        public static List<Vector2> GetConvexHull(IEnumerable<Vector2> points)
+        {
+            var pointsList = points.OrderBy(p => p.X).ThenBy(p => p.Y).ToList();
+
+            if (pointsList.Count < 3)
+                return pointsList;
+
+            var convexHullLower = new List<Vector2>
+            {
+                pointsList[0],
+                pointsList[1]
+            };
+            var convexHullUpper = new List<Vector2>
+            {
+                pointsList[^1],
+                pointsList[^2]
+            };
+
+            // Build the lower hull.
+            for (int i = 2; i < pointsList.Count; i++)
+            {
+                Vector2 c = pointsList[i];
+                while (convexHullLower.Count > 1 && isClockwise(convexHullLower[^2], convexHullLower[^1], c))
+                    convexHullLower.RemoveAt(convexHullLower.Count - 1);
+
+                convexHullLower.Add(c);
+            }
+
+            // Build the upper hull.
+            for (int i = pointsList.Count - 3; i >= 0; i--)
+            {
+                Vector2 c = pointsList[i];
+                while (convexHullUpper.Count > 1 && isClockwise(convexHullUpper[^2], convexHullUpper[^1], c))
+                    convexHullUpper.RemoveAt(convexHullUpper.Count - 1);
+
+                convexHullUpper.Add(c);
+            }
+
+            convexHullLower.RemoveAt(convexHullLower.Count - 1);
+            convexHullUpper.RemoveAt(convexHullUpper.Count - 1);
+
+            convexHullLower.AddRange(convexHullUpper);
+
+            return convexHullLower;
+
+            float crossProduct(Vector2 v1, Vector2 v2) => v1.X * v2.Y - v1.Y * v2.X;
+
+            bool isClockwise(Vector2 a, Vector2 b, Vector2 c) => crossProduct(b - a, c - a) >= 0;
+        }
+
+        public static List<Vector2> GetConvexHull(IEnumerable<IHasPosition> hitObjects) =>
+            GetConvexHull(enumerateStartAndEndPositions(hitObjects));
+
+        private static IEnumerable<Vector2> enumerateStartAndEndPositions(IEnumerable<IHasPosition> hitObjects) =>
+            hitObjects.SelectMany(h =>
             {
                 if (h is IHasPath path)
                 {
@@ -140,6 +217,6 @@ namespace osu.Game.Utils
                 }
 
                 return new[] { h.Position };
-            }));
+            });
     }
 }