module-inspector/Editor/Drawers/SliderAttributeDrawer.cs

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

namespace Module.Inspector.Editor
{
    [CustomPropertyDrawer(typeof(SliderAttribute))]
    internal sealed class SliderAttributeDrawer : DrawerPropertyDrawer
    {
        public override bool Draw(Rect position, DrawerPropertyAttribute attribute, SerializedProperty property, GUIContent label, EditorPropertyUtility.Result result)
        {
            var min = result.GetValueModifier<MinValueAttribute>();
            var max = result.GetValueModifier<MaxValueAttribute>();

            if (min == null || max == null)
                return false;
            
            switch (property.propertyType)
            {
                case SerializedPropertyType.Integer:
                case SerializedPropertyType.Float:
                    DrawRange(position, property, label, min, max);
                    break;
                case SerializedPropertyType.Vector2:
                case SerializedPropertyType.Vector2Int:
                    DrawerMinMax(position, property, label, min, max);
                    break;
                default:
                    return false;
            }

            return true;
        }
        
        public override string GetErrorMessage(SerializedProperty property)
        {
            switch (property.propertyType)
            {
                case SerializedPropertyType.Integer:
                case SerializedPropertyType.Float:
                case SerializedPropertyType.Vector2:
                case SerializedPropertyType.Vector2Int:
                    return "Requires MinValue and MaxValue";
            }
            
            return "Only supports integer, float, vector2 and vector2int";
        }
        
        private void DrawRange(Rect position, SerializedProperty property, GUIContent label, MinValueAttribute minValueAttribute, MaxValueAttribute maxValueAttribute)
        {
            int indentLevel = EditorGUI.indentLevel;
            float indentSpacing = indentLevel * 15.0f;
            EditorGUI.indentLevel = 0;
            
            EditorGUI.BeginProperty(position, label, property);
            {
                float xMin = position.x + indentSpacing;
                var r0 = new Rect(xMin, position.y, EditorGUIUtility.labelWidth - indentSpacing + 2.0f, position.height);
                var r1 = new Rect(r0.xMax, r0.y, position.width - r0.width - indentSpacing, r0.height);

                EditorGUI.LabelField(r0, label);
                
                switch (property.propertyType)
                {
                    case SerializedPropertyType.Integer:
                        property.intValue = EditorGUI.IntSlider(r1, property.intValue, minValueAttribute.intValue, maxValueAttribute.intValue);
                        break;
                    case SerializedPropertyType.Float:
                        property.floatValue = EditorGUI.Slider(r1, property.floatValue, minValueAttribute.floatValue, maxValueAttribute.floatValue);
                        break;
                }
            }
            EditorGUI.EndProperty();
            EditorGUI.indentLevel = indentLevel;
        }

        private void DrawerMinMax(Rect position, SerializedProperty property, GUIContent label, MinValueAttribute min, MaxValueAttribute max)
        {
            const float FLOAT_WIDTH = 50.0f;
            const float FLOAT_SPACING = 8.0f;
            
            int indentLevel = EditorGUI.indentLevel;
            float indentSpacing = indentLevel * 15.0f;
            EditorGUI.indentLevel = 0;
            
            EditorGUI.BeginProperty(position, label, property);
            {
                float xMin = position.x + indentSpacing;
                float width = position.width - indentSpacing;

                var r0 = new Rect(xMin, position.y, EditorGUIUtility.labelWidth - indentSpacing + 2.0f, position.height);
                var r1 = new Rect(r0.xMax, r0.y, FLOAT_WIDTH, r0.height);
                var r2 = new Rect(r1.xMax + FLOAT_SPACING, r1.y, width - r0.width - (FLOAT_WIDTH + FLOAT_SPACING) * 2, r1.height);
                var r3 = new Rect(r2.xMax + FLOAT_SPACING, r2.y, FLOAT_WIDTH, r2.height);
                
                EditorGUI.LabelField(r0, label);
                
                switch (property.propertyType)
                {
                    case SerializedPropertyType.Vector2:
                        Vector2 v = property.vector2Value;
                        float minValue = v.x;
                        float maxValue = v.y;
            
                        minValue = EditorGUI.FloatField(r1, minValue);
                        maxValue = EditorGUI.FloatField(r3, maxValue);
                        EditorGUI.MinMaxSlider(r2, ref minValue, ref maxValue, min.floatValue, max.floatValue);

                        v.x = minValue;
                        v.y = maxValue;
            
                        property.vector2Value = v;
                        break;
                    case SerializedPropertyType.Vector2Int:
                        Vector2Int v2Int = property.vector2IntValue;
                        float minIntValue = v2Int.x;
                        float maxIntValue = v2Int.y;
            
                        minIntValue = EditorGUI.IntField(r1, Mathf.RoundToInt(minIntValue));
                        maxIntValue = EditorGUI.IntField(r3, Mathf.RoundToInt(maxIntValue));
                        EditorGUI.MinMaxSlider(r2, ref minIntValue, ref maxIntValue, min.floatValue, max.floatValue);
            
                        v2Int.x = Mathf.RoundToInt(minIntValue);
                        v2Int.y = Mathf.RoundToInt(maxIntValue);
                        
                        property.vector2IntValue = v2Int;
                        break;
                }
            }
            EditorGUI.EndProperty();
            EditorGUI.indentLevel = indentLevel;
        }
    }
}