Drawing a sprite in editor window

I have a bunch of ScriptableObjects that hold references to Spriters I need in game.
I'd like to have a preview of the selected sprite when viewing the scriptable object.

Is there an attribute that I can put on the Sprite field or other built in way to do this?

If not I think I will make a property drawer that would use GUI.DrawTexture.

 

You mean in an editor extension window?
There a property to draw textures, you could draw the texture of the sprite as a preview.
https://docs.unity3d.com/ScriptReference/EditorGUI.DrawPreviewTexture.html

 

Here's my code to display sprite's texture below the property.
Simply put the PropertyDrawer inside an Editor folder and the PropertyAttribute somewhere next to it (not inside an Editor folder).
Now you can put [PreviewSprite] above any Sprite field and have your sprite image preview.

Code (CSharp):

1. using UnityEngine;
2. namespace UnityEditor {
3. [CustomPropertyDrawer(typeof(PreviewSpriteAttribute))]
4. public class PreviewSpriteDrawer : PropertyDrawer
5. {
6.     const float imageHeight = 100;
7.  
8.     public override float GetPropertyHeight(SerializedProperty property,
9.                                             GUIContent label)
10.     {
11.         if (property.propertyType == SerializedPropertyType.ObjectReference &&
12.             (property.objectReferenceValue as Sprite) != null)
13.         {
14.             return EditorGUI.GetPropertyHeight(property, label, true) + imageHeight + 10;
15.         }
16.         return EditorGUI.GetPropertyHeight(property, label, true);
17.     }
18.  
19.     static string GetPath(SerializedProperty property)
20.     {
21.         string path = property.propertyPath;
22.         int index = path.LastIndexOf(".");
23.         return path.Substring(0, index + 1);
24.     }
25.  
26.     public override void OnGUI(Rect position,
27.                                 SerializedProperty property,
28.                                 GUIContent label)
29.     {
30.         //Draw the normal property field
31.         EditorGUI.PropertyField(position, property, label, true);
32.  
33.         if (property.propertyType == SerializedPropertyType.ObjectReference)
34.         {
35.             var sprite = property.objectReferenceValue as Sprite;
36.             if (sprite != null)
37.             {
38.                 position.y += EditorGUI.GetPropertyHeight(property, label, true) + 5;
39.                 position.height = imageHeight;
40.                 //EditorGUI.DrawPreviewTexture(position, sprite.texture, null, ScaleMode.ScaleToFit, 0);
41.                 GUI.DrawTexture(position, sprite.texture, ScaleMode.ScaleToFit);
42.             }
43.         }
44.     }
45. }
46. }

Code (CSharp):

1. namespace UnityEngine {
2. public class PreviewSpriteAttribute : PropertyAttribute
3. {
4.     public PreviewSpriteAttribute() {}
5. }
6. }

 

This is great but it shows the entire spritesheet when it contains multiple sprites instead of showing only the selected one.
I fixed it by using GUI.DrawTextureWithTexCoords but this method doesn't have the ScaleMode argument for some reason so I just replicated the ScaleToFit functionality myself.

Code (CSharp):

1. using UnityEngine;
2.  
3. namespace UnityEditor
4. {
5.     [CustomPropertyDrawer(typeof(PreviewSpriteAttribute))]
6.     public class PreviewSpriteDrawer : PropertyDrawer
7.     {
8.         const float imageHeight = 100;
9.  
10.         public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
11.         {
12.             if (property.propertyType == SerializedPropertyType.ObjectReference &&
13.                 (property.objectReferenceValue as Sprite) != null)
14.             {
15.                 return EditorGUI.GetPropertyHeight(property, label, true) + imageHeight + 10;
16.             }
17.             return EditorGUI.GetPropertyHeight(property, label, true);
18.         }
19.  
20.         static string GetPath(SerializedProperty property)
21.         {
22.             string path = property.propertyPath;
23.             int index = path.LastIndexOf(".");
24.             return path.Substring(0, index + 1);
25.         }
26.  
27.         public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
28.         {
29.             //Draw the normal property field
30.             EditorGUI.PropertyField(position, property, label, true);
31.  
32.             if (property.propertyType == SerializedPropertyType.ObjectReference)
33.             {
34.                 var sprite = property.objectReferenceValue as Sprite;
35.                 if (sprite != null)
36.                 {
37.                     position.y += EditorGUI.GetPropertyHeight(property, label, true) + 5;
38.                     position.height = imageHeight;
39.  
40.                     //GUI.DrawTexture(position, sprite.texture, ScaleMode.ScaleToFit);
41.                     DrawTexturePreview(position, sprite);
42.                 }
43.             }
44.         }
45.  
46.         private void DrawTexturePreview(Rect position, Sprite sprite)
47.         {
48.             Vector2 fullSize = new Vector2(sprite.texture.width, sprite.texture.height);
49.             Vector2 size = new Vector2(sprite.textureRect.width, sprite.textureRect.height);
50.  
51.             Rect coords = sprite.textureRect;
52.             coords.x /= fullSize.x;
53.             coords.width /= fullSize.x;
54.             coords.y /= fullSize.y;
55.             coords.height /= fullSize.y;
56.  
57.             Vector2 ratio;
58.             ratio.x = position.width / size.x;
59.             ratio.y = position.height / size.y;
60.             float minRatio = Mathf.Min(ratio.x, ratio.y);
61.  
62.             Vector2 center = position.center;
63.             position.width = size.x * minRatio;
64.             position.height = size.y * minRatio;
65.             position.center = center;
66.  
67.             GUI.DrawTextureWithTexCoords(position, sprite.texture, coords);
68.         }
69.     }
70. }

 

At risk of being accused of necroing, I just had to say thanks for this, saved me a load of time and works perfectly.

 

Yeah I really don't wanna necro this thread, but can someone explain how the PreviewSpriteAttribute class works? It just has an empty method, I don't understand lol. Is that class even necessary?
Other than that this worked perfectly for me and I now have sprite previews in my scriptable object editors.

 

Might as well join you in necroing to explain~

PreviewSpriteAttribute defines the attribute that you tag the field with to invoke the PropertyDrawer. The empty method is a constructor, which doesn't do anything because the attribute doesn't need any parameters to work. If you wanted to store, say, a user-defined height value, you would read that in through the constructor like so:

Code (CSharp):

1. namespace UnityEngine {
2.     public class PreviewSpriteAttribute : PropertyAttribute
3.     {
4.         public int _height;
5.         public PreviewSpriteAttribute(int height = 100)
6.         {
7.             _height = height;
8.         }
9.     }
10. }

And then to read the height in the Drawer methods:

Code (CSharp):

1. var attr = attribute as PreviewSpriteAttribute;
2. int height = attr._height;

 

If you need to set both the texture coordinates AND the material, you can use Graphics.DrawTexture. Make sure check for EventType.Repaint before calling the function.

 

Right. Though keep in mind that there's also GUI.DrawTexture with many overloads. It's essentially a wrapper around Graphics.DrawTexture but does already the event check. Though an additional check does not hurt. Actually avoiding the method call could even be better ^^