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

Answer by Edy · Sep 22, 2014 at 05:07 PM

Two alternatives to DrawPreviewTexture that don't use GUIStyle and use the ScaleToFit scaling method: scale down the texture keeping the aspect ratio only when position is smaller than the texture rect.

 // ScaleToFit method, left-aligned at the position of the prefix label
 EditorGUI.LabelField(position, new GUIContent(texture));
 
 // ScaleToFit method, horizontally centered, bottom-aligned, shadow effect
 EditorGUI.DropShadowLabel(position, new GUIContent(texture));

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numberkruncher · Sep 22, 2014 at 05:45 PM 0

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Internally this would still use GUIStyle.

Edy numberkruncher · Jan 13, 2016 at 06:22 PM 0

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I guess that everything use GUIStyle at some point, but I meant that you don't have to create or configure a GUIStyle object explicitly.

Answer 2

Answer by numberkruncher · Sep 19, 2014 at 09:05 PM

I had this issue and came up with a similar workaround to @MalikDrako except without allocating GUIStyle's each time OnGUI events occur.

This aims to function as a drop-in replacement for GUI.DrawTexture:

 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);
     }
 
 }

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BoraxKid · Nov 22, 2017 at 04:49 PM 0

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Perfect thank you! This solution works on Unity 2017.2.0f3

Answer 3

Answer by Simon Says · May 25, 2014 at 05:14 AM

I found out that the texture doesn't flicker if the PropertyDrawer is drawn by a custom Editor. If you know where your PropertyDrawer is going to be used, simply make an empty stub deriving from the Editor for that object, like this:

 [CustomEditor(typeof(ScriptableObject))]
 public class ScriptableObjectInspector : Editor
 {
     // Empty stub so a custom PropertyDrawer with textures would work.
     // (Workaround for Unity bug #514655.)
 }

That's the closest I got to drawing textures with custom texture coordinates (e.g. sprites).

However, remember to put your drawing calls behind:

 if (Event.current.type == EventType.Repaint) {
     EditorGUI.DrawPreviewTexture(rect, texture);
 }

Or you'll get garbage in the supplied position rectangle. The documentation only mentions it for Graphics.DrawTexture(), but it is also needed in this case.

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nsfnotthrowingaway · Nov 20, 2019 at 10:09 PM 0

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Thank you so much! This is the only solution that worked for me.

Drawing a texture in a custom PropertyDrawer

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