tabakrolletjie/loader.py

   1 """ Utilities for loading resource files. """
   2
   3 import json
   4 import os
   5
   6 import pygame.image
   7 import pygame.display
   8
   9
  10 class Loader(object):
  11     """ Load data files from beneath a prefix. """
  12
  13     def __init__(self, prefix):
  14         self._prefix = prefix
  15         self._cache = {}
  16
  17     def full_path(self, *parts):
  18         path = "/".join(parts)
  19         rel_path = os.path.join(*path.split("/"))
  20         abs_path = os.path.join(self._prefix, rel_path)
  21         print abs_path
  22         return abs_path
  23
  24     def open_file(self, *parts):
  25         return file(self.full_path(*parts), "rb")
  26
  27     def load_station(self, *parts):
  28         with self.open_file("stations", *parts) as f:
  29             return json.load(f)
  30
  31     def load_image(self, *parts):
  32         """Return a pygame surface of the requested image."""
  33         fn = self.full_path("images", *parts)
  34         img = self._cache.get(fn, None)
  35         if img is None:
  36             img = pygame.image.load(fn)
  37             # We assume pygame.display has been initialised
  38             # Fix this if that changes
  39             img.convert_alpha(pygame.display.get_surface())
  40             self._cache[fn] = img
  41         return img
  42
  43
  44 _DATA_PREFIX = os.path.abspath(
  45     os.path.join(os.path.dirname(__file__), "..", "data"))
  46
  47 loader = Loader(_DATA_PREFIX)