module-inspector/Editor/Handles/CircleHandleAttributeDrawer.cs

using Module.Inspector.Editor.Utilities;
using UnityEditor;
using UnityEngine;

namespace Module.Inspector.Editor
{
    [CustomPropertyDrawer(typeof(CircleHandleAttribute))]
    internal sealed class CircleHandleAttributeDrawer : HandlePropertyDrawer
    {
        public override void Draw(HandleDrawerPropertyAttribute attribute, SerializedProperty serializedProperty)
        {
            var att = (CircleHandleAttribute)attribute;
            bool hasPositionField = EditorHandleUtility.TryGetWorldPosition(serializedProperty, att.fieldPosition, att.space, out Vector3 worldPosition);
            bool hasRotationField = EditorHandleUtility.TryGetWorldRotation(serializedProperty, att.fieldRotation, att.space, out Quaternion worldRotation);
            float size = GetValue(serializedProperty);
            Color color = Handles.color;

            if (hasPositionField)
                worldPosition = EditorHandleUtility.PositionHandle(worldPosition, worldRotation);
            if (hasRotationField)
                worldRotation = EditorHandleUtility.RotationHandle(worldPosition, worldRotation);

            size = EditorHandleUtility.CircleHandle(worldPosition, worldRotation, size);
            
            if (hasPositionField)
                EditorHandleUtility.SetWorldPosition(serializedProperty, att.fieldPosition, worldPosition, att.space);
            if (hasRotationField)
                EditorHandleUtility.SetWorldRotation(serializedProperty, att.fieldRotation, worldRotation, att.space);
            
            SetValue(serializedProperty, size);
            Handles.color = color;
        }

        private float GetValue(SerializedProperty serializedProperty)
        {
            switch (serializedProperty.propertyType)
            {
                case SerializedPropertyType.Integer:
                    return serializedProperty.intValue;
                case SerializedPropertyType.Float:
                    return serializedProperty.floatValue;
                default:
                    return 1f;
            }
        }
        
        private void SetValue(SerializedProperty serializedProperty, float value)
        {
            switch (serializedProperty.propertyType)
            {
                case SerializedPropertyType.Integer:
                    serializedProperty.intValue = Mathf.RoundToInt(value);
                    break;
                case SerializedPropertyType.Float:
                    serializedProperty.floatValue = value;
                    break;
            }
        }

        public override bool IsValidFor(SerializedProperty serializedProperty)
        {
            switch (serializedProperty.propertyType)
            {
                case SerializedPropertyType.Integer:
                case SerializedPropertyType.Float:
                    return true;
                default:
                    return false;
            }
        }
    }
}