##    pygame - Python Game Library
##    Copyright (C) 2000-2003  Pete Shinners
##              (C) 2004 Joe Wreschnig
##    Windowed Sprite Group Extension
##    Copyright (C) 2008 Bryce Schroeder
##
##    This library is free software; you can redistribute it and/or
##    modify it under the terms of the GNU Library General Public
##    License as published by the Free Software Foundation; either
##    version 2 of the License, or (at your option) any later version.
##
##    This library is distributed in the hope that it will be useful,
##    but WITHOUT ANY WARRANTY; without even the implied warranty of
##    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
##    Library General Public License for more details.
##
##    You should have received a copy of the GNU Library General Public
##    License along with this library; if not, write to the Free
##    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
##
##    Pete Shinners
##    pete@shinners.org
##
##    Bryce Schroeder
##    bryce.schroeder@gmail.com

# flashing bug is probably here
import pygame
from pygame.locals import *
class WindowedGroup(pygame.sprite.Group):
    def __init__(self, *args):
    	pygame.sprite.Group.__init__(*((self,)+args))
	self.current = 0,0
    def clear_window(self, screen, window, cords, background):
       screen.blit(background, window, cords+(window.w,window.h))
    def clear_background(self, surface, window, rects, cords, background):
       for s in rects:
           source = pygame.rect.Rect(s.x+cords[0]-window.x, s.y+cords[1]-window.y,
	                             s.w, s.h)
           surface.blit(background, s, source)
    def draw(self, surface, window, background, cords=(0,0)):
       if cords != self.current:
           self.clear_window(surface, window, cords, background)
           reset = True
	   self.current = cords
       else:
           reset = False
       spritedict = self.spritedict
       surface_blit = surface.blit
       dirty = self.lostsprites
       self.lostsprites = []
       dirty_append = dirty.append
       for s in self.sprites():
           r = spritedict[s]
	   shiftedrect = pygame.rect.Rect(
	                     s.rect.x-cords[0]+window.x, 
			     s.rect.y-cords[1]+window.y, 
			     s.rect.w, 
			     s.rect.h
			     )
	   if (   shiftedrect.x - window.x > window.width
	       or shiftedrect.x - window.x < -shiftedrect.w
	       or shiftedrect.y - window.y > window.height
	       or shiftedrect.y - window.y < -shiftedrect.h): continue
           newrect = surface_blit(s.image, shiftedrect)
           if r is 0:
               dirty_append(newrect)
           else:
               if newrect.colliderect(r):
                   dirty_append(newrect.union(r))
               else:
                   dirty_append(newrect)
                   dirty_append(r)
           spritedict[s] = newrect
       if reset:
           return [window]
       else:
           return dirty