SpritesheetPivotAlign.cs

using System.Collections.Generic;
using UnityEngine;
using UnityEditor;

/// <summary>
/// 
/// Copies the pivot coordinates of a first slice of the spritesheet and applies them to the pivots of other slices in the same spritesheet.
/// This script only works for spritesheets that were sliced using the grid option.
/// How to: select your spritesheet in the project files and go to the menu item to run the command.
/// 
/// Idea stolen from: https://answers.unity.com/questions/761009/unity2d-sprite-editor-multiple-pivot-point-edit.html
/// Original code: https://www.reddit.com/r/Unity3D/comments/1vnvko/bulk_setting_a_sprites_pivot_in_a_spritesheet/
/// 
/// </summary>

public class SpritesheetPivotAlign : MonoBehaviour
{
    [MenuItem("Tools/Sprites/Align pivots in spritesheet")]
    static void SetPivots()
    {

        Object[] textures = GetSelectedTextures();

        Selection.objects = new Object[0];
        foreach (Texture2D texture in textures)
        {
            string path = AssetDatabase.GetAssetPath(texture);
            TextureImporter ti = AssetImporter.GetAtPath(path) as TextureImporter;
            ti.isReadable = true;
            List<SpriteMetaData> newData = new List<SpriteMetaData>();
            for (int i = 0; i < ti.spritesheet.Length; i++)
            {
                SpriteMetaData d = ti.spritesheet[i];
                d.alignment = 9;
                d.pivot = ti.spritesheet[0].pivot;
                newData.Add(d);
            }
            ti.spritesheet = newData.ToArray();
            AssetDatabase.ImportAsset(path, ImportAssetOptions.ForceUpdate);
        }
    }

    static Object[] GetSelectedTextures()
    {
        return Selection.GetFiltered(typeof(Texture2D), SelectionMode.DeepAssets);
    }
}