Unity procedural UI component, Rounded Rect script

RoundedRect.cs

using UnityEngine;
using UnityEngine.UI;

[RequireComponent(typeof(CanvasRenderer))]
public class RoundedRect : Graphic
{
    [SerializeField] private float m_CornerRadius = 10f;
    [SerializeField] private float m_BorderWidth = 1f;
    [SerializeField] private Color m_BorderColor = Color.black;
    [SerializeField] private int m_CornerSegments = 20;

    public float cornerRadius
    {
        get { return m_CornerRadius; }
        set
        {
            m_CornerRadius = value;
            SetVerticesDirty();
        }
    }

    public float borderWidth
    {
        get { return m_BorderWidth; }
        set
        {
            m_BorderWidth = value;
            SetVerticesDirty();
        }
    }

    public Color borderColor
    {
        get { return m_BorderColor; }
        set
        {
            m_BorderColor = value;
            SetVerticesDirty();
        }
    }

    protected override void OnPopulateMesh(VertexHelper vh)
    {
        vh.Clear();

        Rect rect = rectTransform.rect;
        Vector2 pivot = rectTransform.pivot;

        Vector2 bottomLeft = -rect.size * pivot;
        Vector2 topRight = rect.size - rect.size * pivot;

        float minSize = Mathf.Min(rect.width, rect.height);
        float radius = Mathf.Clamp(m_CornerRadius, 0, minSize / 2);

        if (m_BorderWidth > 0)
        {
            // Outer rectangle (border)
            AddRoundedRectangle(vh, bottomLeft, topRight, radius, m_BorderColor);

            // Inner rectangle (fill)
            AddRoundedRectangle(vh,
                bottomLeft + Vector2.one * m_BorderWidth,
                topRight - Vector2.one * m_BorderWidth,
                Mathf.Max(0, radius - m_BorderWidth),
                color);
        }
        else
        {
            // Only fill if there is no border
            AddRoundedRectangle(vh, bottomLeft, topRight, radius, color);
        }
    }

    private void AddRoundedRectangle(VertexHelper vh, Vector2 bottomLeft, Vector2 topRight, float radius, Color vertexColor)
    {
        int startIndex = vh.currentVertCount;

        // Add corners
        AddCorner(vh, bottomLeft + new Vector2(radius, radius), radius, 180, 270, vertexColor);
        AddCorner(vh, new Vector2(topRight.x - radius, bottomLeft.y + radius), radius, 270, 360, vertexColor);
        AddCorner(vh, topRight - new Vector2(radius, radius), radius, 0, 90, vertexColor);
        AddCorner(vh, new Vector2(bottomLeft.x + radius, topRight.y - radius), radius, 90, 180, vertexColor);

        // Add center vertices
        vh.AddVert(new Vector3(bottomLeft.x, bottomLeft.y + radius), vertexColor, Vector2.zero);
        vh.AddVert(new Vector3(bottomLeft.x, topRight.y - radius), vertexColor, Vector2.zero);
        vh.AddVert(new Vector3(bottomLeft.x + radius, bottomLeft.y), vertexColor, Vector2.zero);
        vh.AddVert(new Vector3(topRight.x - radius, bottomLeft.y), vertexColor, Vector2.zero);
        vh.AddVert(new Vector3(topRight.x, bottomLeft.y + radius), vertexColor, Vector2.zero);
        vh.AddVert(new Vector3(topRight.x, topRight.y - radius), vertexColor, Vector2.zero);
        vh.AddVert(new Vector3(topRight.x - radius, topRight.y), vertexColor, Vector2.zero);
        vh.AddVert(new Vector3(bottomLeft.x + radius, topRight.y), vertexColor, Vector2.zero);

        // Add center vertex
        vh.AddVert(new Vector3((bottomLeft.x + topRight.x) / 2, (bottomLeft.y + topRight.y) / 2), vertexColor, Vector2.zero);
        int centerIndex = vh.currentVertCount - 1;

        // Add triangles
        int vertexCount = vh.currentVertCount - startIndex;
        for (int i = startIndex; i < startIndex + vertexCount - 1; i++)
        {
            vh.AddTriangle(i, i + 1, centerIndex);
        }
        vh.AddTriangle(startIndex + vertexCount - 1, startIndex, centerIndex);
    }

    private void AddCorner(VertexHelper vh, Vector2 center, float radius, float startAngle, float endAngle, Color vertexColor)
    {
        float angleStep = (endAngle - startAngle) / m_CornerSegments;

        for (int i = 0; i <= m_CornerSegments; i++)
        {
            float angle = (startAngle + i * angleStep) * Mathf.Deg2Rad;
            float cosAngle = Mathf.Cos(angle);
            float sinAngle = Mathf.Sin(angle);

            float x = center.x + radius * cosAngle;
            float y = center.y + radius * sinAngle;

            vh.AddVert(new Vector3(x, y), vertexColor, Vector2.zero);
        }
    }
}