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

// 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.Linq;
using osu.Framework.Graphics;
using osu.Framework.Input.Events;
using osu.Game.Rulesets.Osu.Objects;
using osu.Game.Screens.Edit.Compose.Components;
using osuTK;

namespace osu.Game.Rulesets.Osu.Edit
{
    public class OsuSelectionHandler : SelectionHandler
    {
        public override ComposeSelectionBox CreateSelectionBox()
            => new ComposeSelectionBox
            {
                CanRotate = true,
                CanScaleX = true,
                CanScaleY = true,

                // OnRotation = handleRotation,
                OnScaleX = handleScaleX,
                OnScaleY = handleScaleY,
            };

        private void handleScaleY(DragEvent e, Anchor reference)
        {
            int direction = (reference & Anchor.y0) > 0 ? -1 : 1;

            if (direction < 0)
            {
                // when resizing from a top drag handle, we want to move the selection first
                if (!moveSelection(new Vector2(0, e.Delta.Y)))
                    return;
            }

            scaleSelection(new Vector2(0, direction * e.Delta.Y));
        }

        private void handleScaleX(DragEvent e, Anchor reference)
        {
            int direction = (reference & Anchor.x0) > 0 ? -1 : 1;

            if (direction < 0)
            {
                // when resizing from a top drag handle, we want to move the selection first
                if (!moveSelection(new Vector2(e.Delta.X, 0)))
                    return;
            }

            scaleSelection(new Vector2(direction * e.Delta.X, 0));
        }

        private void handleRotation(DragEvent e)
        {
            // selectionArea.Rotation += e.Delta.X;
        }

        public override bool HandleMovement(MoveSelectionEvent moveEvent) =>
            moveSelection(moveEvent.InstantDelta);

        private bool scaleSelection(Vector2 scale)
        {
            Vector2 minPosition = new Vector2(float.MaxValue, float.MaxValue);
            Vector2 maxPosition = new Vector2(float.MinValue, float.MinValue);

            // Go through all hitobjects to make sure they would remain in the bounds of the editor after movement, before any movement is attempted
            foreach (var h in SelectedHitObjects.OfType<OsuHitObject>())
            {
                if (h is Spinner)
                {
                    // Spinners don't support position adjustments
                    continue;
                }

                // Stacking is not considered
                minPosition = Vector2.ComponentMin(minPosition, Vector2.ComponentMin(h.EndPosition, h.Position));
                maxPosition = Vector2.ComponentMax(maxPosition, Vector2.ComponentMax(h.EndPosition, h.Position));
            }

            Vector2 size = maxPosition - minPosition;
            Vector2 newSize = size + scale;

            foreach (var h in SelectedHitObjects.OfType<OsuHitObject>())
            {
                if (h is Spinner)
                {
                    // Spinners don't support position adjustments
                    continue;
                }

                if (scale.X != 1)
                    h.Position = new Vector2(minPosition.X + (h.X - minPosition.X) / size.X * newSize.X, h.Y);
                if (scale.Y != 1)
                    h.Position = new Vector2(h.X, minPosition.Y + (h.Y - minPosition.Y) / size.Y * newSize.Y);
            }

            return true;
        }

        private bool moveSelection(Vector2 delta)
        {
            Vector2 minPosition = new Vector2(float.MaxValue, float.MaxValue);
            Vector2 maxPosition = new Vector2(float.MinValue, float.MinValue);

            // Go through all hitobjects to make sure they would remain in the bounds of the editor after movement, before any movement is attempted
            foreach (var h in SelectedHitObjects.OfType<OsuHitObject>())
            {
                if (h is Spinner)
                {
                    // Spinners don't support position adjustments
                    continue;
                }

                // Stacking is not considered
                minPosition = Vector2.ComponentMin(minPosition, Vector2.ComponentMin(h.EndPosition + delta, h.Position + delta));
                maxPosition = Vector2.ComponentMax(maxPosition, Vector2.ComponentMax(h.EndPosition + delta, h.Position + delta));
            }

            if (minPosition.X < 0 || minPosition.Y < 0 || maxPosition.X > DrawWidth || maxPosition.Y > DrawHeight)
                return false;

            foreach (var h in SelectedHitObjects.OfType<OsuHitObject>())
            {
                if (h is Spinner)
                {
                    // Spinners don't support position adjustments
                    continue;
                }

                h.Position += delta;
            }

            return true;
        }
    }
}