A custom property drawer for matrices

Matrix4x4Drawer.cs

using System;
using UnityEditor;
using UnityEngine;

[CustomPropertyDrawer(typeof(Matrix4x4))]
public sealed class Matrix4x4Drawer : PropertyDrawer
{
    public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
    {
        return (EditorGUIUtility.singleLineHeight + 2) * 4 - 2;
    }

    public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
    {
        float labelWidth = EditorGUIUtility.labelWidth;
        float lineHeight = EditorGUIUtility.singleLineHeight;
        float indent = EditorGUI.indentLevel * 14;

        GUI.Label(new Rect(position.x + indent, position.y, labelWidth - indent, lineHeight), label);

        float left = position.x + labelWidth;
        float width = (position.width - labelWidth) / 4;

        for (int y = 0; y < 4; y++)
        {
            for (int x = 0; x < 4; x++)
            {
                property.Next(true);

                // The math here probably could be simplified. I wanted to make sure the gaps between the
                // columns are exactly 2 pixels at all times. Because aesthetics.
                float x0 = Mathf.Round(left + width * x) + 2;
                float x1 = Mathf.Round(left + width * (x + 1));
                var rect = new Rect(x0 - 15, position.y + y * (lineHeight + 2), x1 - x0 + 15, lineHeight);

                // Avoid displaying useless values values like 6.123234e-17
                float oldValue = (float)Math.Round(property.floatValue, 6);
                float newValue = EditorGUI.FloatField(rect, oldValue);
                if (newValue != oldValue)
                    property.floatValue = newValue;
            }
        }
    }
}