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();
	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);
	UnityEditor.Handles.EndGUI();
}

void OnDrawGizmos()
{
   #if UNITY_EDITOR
   UnityEditor.Handles.color = Color.white;
   UnityEditor.Handles.Label( pointA.position, "Point A" );
   #endif
}