From 4e27b4e10d7fd4f66097ece17a8c51b80233a363 Mon Sep 17 00:00:00 2001
From: Neil <neil@dip.sun.ac.za>
Date: Sun, 11 May 2014 21:52:20 +0200
Subject: [PATCH] The world is invalid (sometimes, when desirable)

---
 naja/events.py       | 10 ++++++++++
 naja/widgets/base.py |  6 ++++++
 2 files changed, 16 insertions(+)

diff --git a/naja/events.py b/naja/events.py
index 4d3fb07..0e102ed 100644
--- a/naja/events.py
+++ b/naja/events.py
@@ -35,3 +35,13 @@ class QuitGameEvent(NajaEvent):
     @classmethod
     def post(cls):
         super(QuitGameEvent, cls).post()
+
+
+class InvalidateTheWorld(NajaEvent):
+    # This is used to signal to all the widgets that the world has changed
+    # and cached state may need to be recreated
+    TYPE = "INVALIDATE"
+
+    @classmethod
+    def post(cls):
+        super(InvalidateTheWorld, cls).post()
diff --git a/naja/widgets/base.py b/naja/widgets/base.py
index bda00a4..133cc53 100644
--- a/naja/widgets/base.py
+++ b/naja/widgets/base.py
@@ -1,4 +1,5 @@
 import pygame
+from naja.events import InvalidateTheWorld
 
 
 class Widget(object):
@@ -27,6 +28,11 @@ class Widget(object):
 
     def handle_event(self, ev):
         '''Return True if the event has been handled'''
+        if InvalidateTheWorld.matches(ev):
+            # Invalidate has special handling. Widgets should never return
+            # True for for this event
+            self._prepared = False
+            return False
         return False
 
 
-- 
2.34.1