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     _is_selectable_func = None
  11
  12     def __init__(self, pos, size=None):
  13         self.pos = pos
  14         self.size = size or (0, 0)
  15         self._prepared = False
  16         self.callbacks = defaultdict(list)
  17
  18     @property
  19     def rect(self):
  20         return pygame.Rect(self.pos, self.size)
  21
  22     def render(self, surface):
  23         '''Draw the widget onto surface'''
  24         if not self._prepared:
  25             self.prepare()
  26             self._prepared = True
  27         self.draw(surface)
  28
  29     def draw(self, surface):
  30         '''The overrideable bit of widget drawing'''
  31         raise NotImplemented()
  32
  33     def prepare(self):
  34         '''Prepare the widget for drawing. This usually caches a surface.'''
  35
  36     def handle_event(self, ev):
  37         '''Return True if the event has been handled'''
  38         if InvalidateTheWorld.matches(ev):
  39             # Invalidate has special handling. Widgets should never return
  40             # True for for this event
  41             self._prepared = False
  42             return False
  43         if SelectEvent.matches(ev) or ev.type == pgl.MOUSEBUTTONDOWN:
  44             return self.callback('click')
  45         return False
  46
  47     def add_callback(self, event, callback):
  48         self.callbacks[event].append(callback)
  49
  50     def callback(self, event):
  51         for callback in self.callbacks[event]:
  52             callback(event)
  53         return bool(self.callbacks[event])
  54
  55     def set_selectable_callback(self, func):
  56         self._is_selectable_func = func
  57
  58     def is_selectable(self):
  59         """Return False if this widget isn't selectable by SelectorWidget."""
  60         if self._is_selectable_func is not None:
  61             return self._is_selectable_func()
  62         else:
  63             return True
  64
  65
  66 class Container(object):
  67     def __init__(self, *widgets):
  68         self.widgets = []
  69         for widget in widgets:
  70             self.add(widget)
  71
  72     def add(self, widget):
  73         self.widgets.append(widget)
  74
  75     def render(self, surface):
  76         for widget in self.widgets:
  77             widget.render(surface)
  78
  79     def handle_event(self, ev):
  80         if hasattr(ev, 'pos'):
  81             for widget in self.widgets:
  82                 if isinstance(widget, Container):
  83                     if widget.handle_event(ev):
  84                         return True
  85                 elif widget.rect.collidepoint(ev.pos):
  86                     if widget.handle_event(ev):
  87                         return True
  88         else:
  89             for widget in self.widgets:
  90                 if widget.handle_event(ev):
  91                     return True
  92         return False