Unity editor window to bulk replace sprites of selected SpriteRenderer components

SpriteReplacer.cs

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



public class SpriteReplacerSettingsAsset
{
    [MenuItem("Assets/Create/SpriteReplacerSettings")]
    public static void CreateAsset()
    {
        SpriteReplacerSettings asset = ScriptableObject.CreateInstance<SpriteReplacerSettings>();

        AssetDatabase.CreateAsset(asset, "Assets/SpriteReplacerSettings.asset");
        AssetDatabase.SaveAssets();

        EditorUtility.FocusProjectWindow();

        Selection.activeObject = asset;
    }
}

public class SpriteReplacer : EditorWindow
{
    public SpriteReplacerSettings settings;
    public bool compactView = false;

    Vector2 scrollposition = Vector2.zero;
    List<SpriteRenderer> targets = new List<SpriteRenderer>();
    List<int> targetReplacement = new List<int>();

    // Add menu named "My Window" to the Window menu
    [MenuItem("Window/SpriteReplacer")]
    static void Init()
    {
        // Get existing open window or if none, make a new one:
        SpriteReplacer window = (SpriteReplacer)EditorWindow.GetWindow(typeof(SpriteReplacer));
        window.minSize = new Vector2(200, 400);
        window.Show();
    }

    void OnEnable()
    {
        if (EditorPrefs.HasKey("SpriteReplacer_Setting"))
        {
            string objectPath = EditorPrefs.GetString("SpriteReplacer_Setting");
            settings = AssetDatabase.LoadAssetAtPath(objectPath, typeof(SpriteReplacerSettings)) as SpriteReplacerSettings;
        }
    }

    private void OnDisable()
    {
        EditorUtility.SetDirty(settings);
        AssetDatabase.SaveAssets();
        AssetDatabase.Refresh();
    }

    void OnGUI()
    {
        compactView = EditorGUILayout.Toggle("Compact View", compactView);
        if (!settings)
        {
            RenderSetup();
            return;
        }

        int columns = Mathf.FloorToInt(EditorGUIUtility.currentViewWidth / 150);
        RenderSpritesList(columns:columns);
        TargetSelection();
        EditorGUILayout.LabelField($"Will apply change to {targets.Count} gameObjects", GUI.skin.GetStyle("HelpBox"));
        ReplacementButton();
    }

    public string GetProjectName()
    {
        string[] s = Application.dataPath.Split('/');
        string projectName = s[s.Length - 2];
        Debug.Log("project = " + projectName);
        return projectName;
    }

    private void RenderSetup()
    {
        settings = (SpriteReplacerSettings)EditorGUILayout.ObjectField("Settings asset", settings, typeof(SpriteReplacerSettings), false);
    }

    private Sprite SpriteField(string label, Sprite sprite)
    {
        if (compactView)
        {
            return (Sprite)EditorGUILayout.ObjectField(sprite, typeof(Sprite), true);
        }else
        {
            return (Sprite)EditorGUILayout.ObjectField(label, sprite, typeof(Sprite), true);
        }
    }

    private void RenderSpritesList(int columns = 1)
    {
        scrollposition = EditorGUILayout.BeginScrollView(scrollposition);

        EditorGUILayout.BeginVertical();
        if (settings.toReplace.Count == 0)
        {
            settings.toReplace.Add(null);
            settings.replacement.Add(null);
        }

        if (GUILayout.Button("Add Replacement"))
        {
            settings.toReplace.Add(null);
            settings.replacement.Add(null);
        }


        EditorGUILayout.BeginHorizontal();
        
        int rowsPerColumn = settings.toReplace.Count  / columns;
        for (int column = 0; column < columns; column++)
        {
            EditorGUILayout.BeginVertical();
            int rowsAlreadyPlaced = rowsPerColumn * column;
            int rowsLeftToPlace = settings.toReplace.Count - rowsAlreadyPlaced;
            int rowsInThisColumn = Math.Min(rowsLeftToPlace, rowsPerColumn);
            for (int i = 0 + rowsAlreadyPlaced; i < rowsInThisColumn + rowsAlreadyPlaced; i++)
            {
                EditorGUILayout.BeginHorizontal();
                if (GUILayout.Button("-", GUILayout.Width(18), GUILayout.Height(18)))
                {
                    settings.toReplace.Remove(settings.toReplace[i]);
                    settings.replacement.Remove(settings.replacement[i]);
                }
                EditorGUIUtility.labelWidth = 1;
                settings.toReplace[i] = SpriteField("", settings.toReplace[i]);
                EditorGUIUtility.labelWidth = 1;
                settings.replacement[i] = SpriteField("", settings.replacement[i]);
           
                EditorGUILayout.EndHorizontal();
            }
            EditorGUILayout.EndVertical();

            if(column < columns - 1)
                GUILayout.FlexibleSpace();
        }
        
        EditorGUILayout.EndHorizontal();
        EditorGUILayout.EndVertical();
        EditorGUILayout.EndScrollView();

        EditorGUIUtility.labelWidth = 0;
    }

    private void TargetSelection()
    {
        if (GUILayout.Button("Select Targets"))
        {
            List<GameObject> newSelection = new List<GameObject>();
            targets.Clear();
            targetReplacement.Clear();
            SpriteRenderer[] spriteRenderers = FindObjectsOfType<SpriteRenderer>();
            foreach (SpriteRenderer renderer in spriteRenderers)
            {
                for (int i = 0; i < settings.toReplace.Count; i++)
                {
                    if (renderer.sprite.name == settings.toReplace[i].name)
                    {
                        newSelection.Add(renderer.gameObject);
                        targets.Add(renderer);
                        targetReplacement.Add(i);

                    }
                }
            }
            Selection.objects = newSelection.ToArray();
        }
    }

    private void ReplacementButton()
    {
        if (Selection.objects.Length > 0 && GUILayout.Button("Apply to selection!", GUILayout.Height(40)))
        {
            for (int i = 0; i < targets.Count; i++)
            {
                targets[i].sprite = settings.replacement[targetReplacement[i]];
            }
        }
    }
}

SpriteReplacerSettings.cs

using UnityEngine;
using System.Collections.Generic;

public class SpriteReplacerSettings : ScriptableObject
{
    public List<Sprite> toReplace;
    public List<Sprite> replacement;
}