naja/widgets/base.py

   1 from collections import defaultdict
   2
   3 import pygame
   4 from pygame import locals as pgl
   5
   6 from naja.events import InvalidateTheWorld, SelectEvent
   7
   8
   9 class Widget(object):
  10     def __init__(self, pos, size=None):
  11         self.pos = pos
  12         self.size = size or (0, 0)
  13         self._prepared = False
  14         self.callbacks = defaultdict(list)
  15
  16     @property
  17     def rect(self):
  18         return pygame.Rect(self.pos, self.size)
  19
  20     def render(self, surface):
  21         '''Draw the widget onto surface'''
  22         if not self._prepared:
  23             self.prepare()
  24             self._prepared = True
  25         self.draw(surface)
  26
  27     def draw(self, surface):
  28         '''The overrideable bit of widget drawing'''
  29         raise NotImplemented()
  30
  31     def prepare(self):
  32         '''Prepare the widget for drawing. This usually caches a surface.'''
  33
  34     def handle_event(self, ev):
  35         '''Return True if the event has been handled'''
  36         if InvalidateTheWorld.matches(ev):
  37             # Invalidate has special handling. Widgets should never return
  38             # True for for this event
  39             self._prepared = False
  40             return False
  41         if SelectEvent.matches(ev) or ev.type == pgl.MOUSEBUTTONDOWN:
  42             return self.callback('click')
  43         return False
  44
  45     def add_callback(self, event, callback):
  46         self.callbacks[event].append(callback)
  47
  48     def callback(self, event):
  49         for callback in self.callbacks[event]:
  50             callback(event)
  51         return bool(self.callbacks[event])
  52
  53
  54 class Container(object):
  55     def __init__(self, *widgets):
  56         self.widgets = []
  57         for widget in widgets:
  58             self.add(widget)
  59
  60     def add(self, widget):
  61         self.widgets.append(widget)
  62
  63     def render(self, surface):
  64         for widget in self.widgets:
  65             widget.render(surface)
  66
  67     def handle_event(self, ev):
  68         if hasattr(ev, 'pos'):
  69             for widget in self.widgets:
  70                 if isinstance(widget, Container):
  71                     if widget.handle_event(ev):
  72                         return True
  73                 elif widget.rect.collidepoint(ev.pos):
  74                     if widget.handle_event(ev):
  75                         return True
  76         else:
  77             for widget in self.widgets:
  78                 if widget.handle_event(ev):
  79                     return True
  80         return False