CompositeCollider2DGizmo.cs

using System.Collections.Generic;
using System.Linq;
using UnityEditor;
using UnityEngine;

namespace Kogane.Internal
{
    internal static class CompositeCollider2DGizmo
    {
        [DrawGizmo
        (
            GizmoType.NotInSelectionHierarchy |
            GizmoType.Selected |
            GizmoType.NonSelected
        )]
        private static void Draw
        (
            CompositeCollider2D compositeCollider2D,
            GizmoType           gizmoType
        )
        {
            var color = Color.red;
            var width = 8;

            var transform = compositeCollider2D.transform;
            var pathCount = compositeCollider2D.pathCount;
            var points    = new List<Vector2>();

            Handles.color = color;

            for ( var i = 0; i < pathCount; i++ )
            {
                points.Clear();
                compositeCollider2D.GetPath( i, points );
                points.Add( points[ 0 ] );

                Handles.DrawAAPolyLine
                (
                    lineTex: EditorGUIUtility.whiteTexture,
                    width: width,
                    points: points
                        .Select( x => TransformPointUnscaled( transform, x ) )
                        .ToArray()
                );
            }

            static Vector3 TransformPointUnscaled
            (
                Transform  transform,
                in Vector3 position
            )
            {
                var localToWorldMatrix = Matrix4x4.TRS
                (
                    pos: transform.position,
                    q: transform.rotation,
                    s: Vector3.one
                );

                return localToWorldMatrix.MultiplyPoint3x4( position );
            }
        }
    }
}