Call from OnDrawGizmos() to draw text at Unity3D glocal position in Editor

gistfile1.cs

static void DrawString(string text, Vector3 worldPos, Color? colour = null) {
	UnityEditor.Handles.BeginGUI();
        var originalColor = GUI.color;
        if (colour.HasValue)
        {
            GUI.color = colour.Value;
        }
        var view = UnityEditor.SceneView.currentDrawingSceneView;
        Vector3 screenPos = view.camera.WorldToScreenPoint(worldPos);
        Vector2 size = GUI.skin.label.CalcSize(new GUIContent(text));
        GUI.Label(new Rect(screenPos.x - (size.x / 2), -screenPos.y + view.position.height + 4, size.x, size.y), text);

        GUI.color = originalColor;
        UnityEditor.Handles.EndGUI();
}