tabakrolletjie/loader.py

   1 """ Utilities for loading resource files. """
   2
   3 import json
   4 import os
   5
   6 import pygame.image
   7 import pygame.font
   8 import pygame.display
   9 import pygame.mixer
  10
  11 from .constants import DEBUG
  12 from .transforms import NullTransform
  13
  14
  15 class Loader(object):
  16     """ Load data files from beneath a prefix. """
  17
  18     NULL_TRANSFORM = NullTransform()
  19
  20     def __init__(self, prefix):
  21         self._prefix = prefix
  22         self._cache = {}
  23
  24     def full_path(self, *parts):
  25         path = "/".join(parts)
  26         rel_path = os.path.join(*path.split("/"))
  27         abs_path = os.path.join(self._prefix, rel_path)
  28         if DEBUG:
  29             print abs_path
  30         return abs_path
  31
  32     def open_file(self, *parts):
  33         return file(self.full_path(*parts), "rb")
  34
  35     def load_station(self, *parts):
  36         with self.open_file("stations", *parts) as f:
  37             return json.load(f)
  38
  39     def load_image(self, *parts, **kwargs):
  40         """Return a pygame surface of the requested image."""
  41         fn = self.full_path("images", *parts)
  42         transform = kwargs.pop("transform", self.NULL_TRANSFORM)
  43         img = self._cache.get((fn, transform), None)
  44         if img is None:
  45             img = pygame.image.load(fn)
  46             # We assume pygame.display has been initialised
  47             # Fix this if that changes
  48             img.convert_alpha(pygame.display.get_surface())
  49             img = transform.apply(img)
  50             self._cache[(fn, transform)] = img
  51         return img
  52
  53     def load_font(self, *parts, **kwargs):
  54         """Return a pygame font of the given size"""
  55         size = kwargs.get('size', 12)
  56         fn = self.full_path("fonts", *parts)
  57         font = pygame.font.Font(fn, size)
  58         # Do we need to cache this?
  59         return font
  60
  61     def load_sound(self, *parts):
  62         """Return a pygame sound"""
  63         fn = self.full_path("sounds", *parts)
  64         sound = self._cache.get(fn, None)
  65         if not sound:
  66             sound = pygame.mixer.Sound(fn)
  67             self._cache[fn] = sound
  68         return sound
  69
  70
  71 _DATA_PREFIX = os.path.abspath(
  72     os.path.join(os.path.dirname(__file__), "..", "data"))
  73
  74 loader = Loader(_DATA_PREFIX)