Drawing a texture in a custom PropertyDrawer

Question

I am trying to create a custom property drawer for a type that should be displayed as a 2D image, but when I use EditorGUI.DrawPreviewTexture or GUI.DrawTexture to draw the image, it disappears after a short time, and reappears for a short time when the inspector is updated. How do I properly draw a texture in a PropertyDrawer?

Minimal code:

 [CustomPropertyDrawer (typeof (testObj))]
 public class testObjDrawer : PropertyDrawer {
     int tSize = 128;
     Texture2D texture;
     
     public override void OnGUI(Rect pos, SerializedProperty prop, GUIContent label) {
         if (texture == null)
             InitializeTexture();
         EditorGUI.BeginProperty (pos, label, prop);
         pos = EditorGUI.PrefixLabel (pos, GUIUtility.GetControlID(FocusType.Passive), label);
         EditorGUI.DrawPreviewTexture(pos, texture);
         EditorGUI.EndProperty ();
     }
     
     private void InitializeTexture() {
         texture = new Texture2D(tSize, tSize,TextureFormat.RGB24,false);
         //tex = new Texture2D(tSize, tSize);
         Color32[] clr = new Color32[tSize * tSize];
         for (int i = 0; i < clr.Length; i++) 
             clr[i] = Color.black;
         texture.SetPixels32(clr);
         texture.Apply();
     }
 }

Answer 1

This script copies the sprite to a new texture, not optimized but seems to work. Caveat: The texture must be set as Read/Write Enabled in import settings.

 public static class GUIHelper
 {
     private static GUIStyle s_TempStyle = new GUIStyle();
 
     public static void DrawTexture(Rect position, Texture2D texture)
     {
         if (Event.current.type != EventType.Repaint)
             return;
 
         s_TempStyle.normal.background = texture;
         s_TempStyle.Draw(position, GUIContent.none, false, false, false, false);
     }
 
     public static void DrawTexture(Rect position, Sprite sprite)
     {
         if (Event.current.type != EventType.Repaint)
             return;
 
         //The texture must be set as Read/Write Enabled in import settings.
 
         Texture2D texture = new Texture2D((int)sprite.rect.width, (int)sprite.rect.height, sprite.texture.format, false);
         Color[] pixels = sprite.texture.GetPixels((int)sprite.rect.x, (int)sprite.rect.y, (int)sprite.rect.width, (int)sprite.rect.height);
         texture.SetPixels(pixels);
         texture.Apply();
 
         s_TempStyle.normal.background = texture;
         s_TempStyle.Draw(position, GUIContent.none, false, false, false, false);
     }
 
 }

Answer 2

Unity: 5.6.1f1

Couldn't get scriptableobject sprites to draw consistently in a property drawer. The default EditorGUI.ObjectField when large enough to show the icon would randomly flicker the sprite and render it with a delay after clicking in the inspector panel.

Bunch of helpful tips in this thread. In the end I changed the height of the ObjectField so the default icon is not drawn and use a GUIStyle to render the sprite as a background. Using this method I can mash the arrow key down through my scriptableobjects and the sprites show instantly with now weirdness in the inspector.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEditor;
 
 [CustomPropertyDrawer(typeof(Sprite))]
 public class SpriteDrawer : PropertyDrawer {
 
     private static GUIStyle s_TempStyle = new GUIStyle();
     
     public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
     {                                        
         var ident = EditorGUI.indentLevel;
         EditorGUI.indentLevel = 0;
 
         Rect spriteRect;
         
         //create object field for the sprite
         spriteRect = new Rect(position.x, position.y, position.width, EditorGUIUtility.singleLineHeight);
         property.objectReferenceValue = EditorGUI.ObjectField(spriteRect, property.name, property.objectReferenceValue, typeof(Sprite), false);
 
         //if this is not a repain or the property is null exit now
         if (Event.current.type != EventType.Repaint || property.objectReferenceValue == null)
             return;
 
         //draw a sprite
         Sprite sp = property.objectReferenceValue as Sprite;
 
         spriteRect.y += EditorGUIUtility.singleLineHeight+4;
         spriteRect.width = 64;
         spriteRect.height = 64;        
         s_TempStyle.normal.background = sp.texture;
         s_TempStyle.Draw(spriteRect, GUIContent.none, false, false, false, false);
                 
         EditorGUI.indentLevel = ident;
     }
 
     public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
     {
         return base.GetPropertyHeight(property, label) + 70f;
     }
 }

Answer 3

Answer by DrummerB · Aug 15, 2018 at 07:53 PM

Since 2017.3 you can override CanCacheInspectorGUI to fix this issue:

 public override bool CanCacheInspectorGUI(SerializedProperty property)
 {
     return false;
 }

More details here.

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Nonym · Feb 25, 2019 at 04:06 PM 0

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Thanks, this is the best solution.

Drawing a texture in a custom PropertyDrawer

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