ShowIfDrawer.cs

#if UNITY_EDITOR
using UnityEditor;
using UnityEngine;
 
#pragma warning disable IDE0130
namespace SCG.Editor
#pragma warning restore IDE0130
{
    [CustomPropertyDrawer(typeof(ShowIfAttribute))]
    internal sealed class ShowIfDrawer : PropertyDrawer
    {
        public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
        {
            if (!ShouldShow(property))
                return;
 
            if (ConditionalMemberEvaluator.TryGetBuiltInDrawer(property, fieldInfo, out var builtInDrawer))
            {
                ConditionalMemberEvaluator.DrawBuiltInDrawer(builtInDrawer, position, property, label);
                return;
            }
 
            EditorGUI.PropertyField(position, property, label, true);
        }
 
        public override float GetPropertyHeight(SerializedProperty property, GUIContent label) =>
            !ShouldShow(property)
                ? 0f
                : ConditionalMemberEvaluator.TryGetBuiltInDrawer(property, fieldInfo, out var builtInDrawer)
                    ? ConditionalMemberEvaluator.GetBuiltInDrawerHeight(builtInDrawer, property, label)
                    : EditorGUI.GetPropertyHeight(property, label, true);
 
        private bool ShouldShow(SerializedProperty property) =>
            attribute is not ShowIfAttribute showIf || property == null ||
            ConditionalMemberEvaluator.ShouldShow(property, showIf);
    }
}
#endif