RectTransformExtensions.cs

using UnityEngine;
 
public enum AnchorPresets
    {
    TopLeft,
    TopCenter,
    TopRight,

    MiddleLeft,
    MiddleCenter,
    MiddleRight,

    BottomLeft,
    BottonCenter,
    BottomRight,
    BottomStretch,

    VertStretchLeft,
    VertStretchRight,
    VertStretchCenter,

    HorStretchTop,
    HorStretchMiddle,
    HorStretchBottom,

    StretchAll
}
 
public enum PivotPresets
{
    TopLeft,
    TopCenter,
    TopRight,

    MiddleLeft,
    MiddleCenter,
    MiddleRight,

    BottomLeft,
    BottomCenter,
    BottomRight,
}
/// <summary>
/// A simplified rect made of 4 floats
/// </summary>
public struct Rect4
{
    public Rect4(float top,float bottom,float left,float right)
    {
        this.top = top;
        this.bottom = bottom;
        this.left = left;
        this.right = right;
    }
    public float top;
    public float bottom;
    public float left;
    public float right;
}
 
public static class RectTransformExtensions
{
    public static void SetAnchor(this RectTransform source, AnchorPresets allign, int offsetX=0, int offsetY=0)
    {
        source.anchoredPosition = new Vector3(offsetX, offsetY, 0);

        switch (allign)
        {
            case(AnchorPresets.TopLeft):
            {
                source.anchorMin = new Vector2(0, 1);
                source.anchorMax = new Vector2(0, 1);
                break;
            }
            case (AnchorPresets.TopCenter):
            {
                source.anchorMin = new Vector2(0.5f, 1);
                source.anchorMax = new Vector2(0.5f, 1);
                break;
            }
            case (AnchorPresets.TopRight):
            {
                source.anchorMin = new Vector2(1, 1);
                source.anchorMax = new Vector2(1, 1);
                break;
            }

            case (AnchorPresets.MiddleLeft):
            {
                source.anchorMin = new Vector2(0, 0.5f);
                source.anchorMax = new Vector2(0, 0.5f);
                break;
            }
            case (AnchorPresets.MiddleCenter):
            {
                source.anchorMin = new Vector2(0.5f, 0.5f);
                source.anchorMax = new Vector2(0.5f, 0.5f);
                break;
            }
            case (AnchorPresets.MiddleRight):
            {
                source.anchorMin = new Vector2(1, 0.5f);
                source.anchorMax = new Vector2(1, 0.5f);
                break;
            }

            case (AnchorPresets.BottomLeft):
            {
                source.anchorMin = new Vector2(0, 0);
                source.anchorMax = new Vector2(0, 0);
                break;
            }
            case (AnchorPresets.BottonCenter):
            {
                source.anchorMin = new Vector2(0.5f, 0);
                source.anchorMax = new Vector2(0.5f,0);
                break;
            }
            case (AnchorPresets.BottomRight):
            {
                source.anchorMin = new Vector2(1, 0);
                source.anchorMax = new Vector2(1, 0);
                break;
            }

            case (AnchorPresets.HorStretchTop):
            {
                source.anchorMin = new Vector2(0, 1);
                source.anchorMax = new Vector2(1, 1);
                break;
            }
            case (AnchorPresets.HorStretchMiddle):
            {
                source.anchorMin = new Vector2(0, 0.5f);
                source.anchorMax = new Vector2(1, 0.5f);
                break;
            }
            case (AnchorPresets.HorStretchBottom):
            {
                source.anchorMin = new Vector2(0, 0);
                source.anchorMax = new Vector2(1, 0);
                break;
            }

            case (AnchorPresets.VertStretchLeft):
            {
                source.anchorMin = new Vector2(0, 0);
                source.anchorMax = new Vector2(0, 1);
                break;
            }
            case (AnchorPresets.VertStretchCenter):
            {
                source.anchorMin = new Vector2(0.5f, 0);
                source.anchorMax = new Vector2(0.5f, 1);
                break;
            }
            case (AnchorPresets.VertStretchRight):
            {
                source.anchorMin = new Vector2(1, 0);
                source.anchorMax = new Vector2(1, 1);
                break;
            }

            case (AnchorPresets.StretchAll):
            {
                source.anchorMin = new Vector2(0, 0);
                source.anchorMax = new Vector2(1, 1);
                break;
            }
        }
    }

    public static void SetPivot(this RectTransform source, PivotPresets preset)
    {

        switch (preset)
        {
            case (PivotPresets.TopLeft):
            {
                source.pivot = new Vector2(0, 1);
                break;
            }
            case (PivotPresets.TopCenter):
            {
                source.pivot = new Vector2(0.5f, 1);
                break;
            }
            case (PivotPresets.TopRight):
            {
                source.pivot = new Vector2(1, 1);
                break;
            }

            case (PivotPresets.MiddleLeft):
            {
                source.pivot = new Vector2(0, 0.5f);
                break;
            }
            case (PivotPresets.MiddleCenter):
            {
                source.pivot = new Vector2(0.5f, 0.5f);
                break;
            }
            case (PivotPresets.MiddleRight):
            {
                source.pivot = new Vector2(1, 0.5f);
                break;
            }

            case (PivotPresets.BottomLeft):
            {
                source.pivot = new Vector2(0, 0);
                break;
            }
            case (PivotPresets.BottomCenter):
            {
                source.pivot = new Vector2(0.5f, 0);
                break;
            }
            case (PivotPresets.BottomRight):
            {
                source.pivot = new Vector2(1, 0);
                break;
            }
        }
    }
    public static void SetRect(this RectTransform source, Rect4 rect)
    {
        source.offsetMin = new Vector2(rect.left, rect.bottom);
        source.offsetMax = new Vector2(-rect.right, -rect.top);
    }
}