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
  10 from .constants import DEBUG
  11
  12
  13 class Loader(object):
  14     """ Load data files from beneath a prefix. """
  15
  16     def __init__(self, prefix):
  17         self._prefix = prefix
  18         self._cache = {}
  19
  20     def full_path(self, *parts):
  21         path = "/".join(parts)
  22         rel_path = os.path.join(*path.split("/"))
  23         abs_path = os.path.join(self._prefix, rel_path)
  24         if DEBUG:
  25             print abs_path
  26         return abs_path
  27
  28     def open_file(self, *parts):
  29         return file(self.full_path(*parts), "rb")
  30
  31     def load_station(self, *parts):
  32         with self.open_file("stations", *parts) as f:
  33             return json.load(f)
  34
  35     def load_image(self, *parts):
  36         """Return a pygame surface of the requested image."""
  37         fn = self.full_path("images", *parts)
  38         img = self._cache.get(fn, None)
  39         if img is None:
  40             img = pygame.image.load(fn)
  41             # We assume pygame.display has been initialised
  42             # Fix this if that changes
  43             img.convert_alpha(pygame.display.get_surface())
  44             self._cache[fn] = img
  45         return img
  46
  47     def load_font(self, *parts, **kwargs):
  48         """Return a pygame font of the given size"""
  49         size = kwargs.get('size', 12)
  50         fn = self.full_path("fonts", *parts)
  51         font = pygame.font.Font(fn, size)
  52         # Do we need to cache this?
  53         return font
  54
  55
  56 _DATA_PREFIX = os.path.abspath(
  57     os.path.join(os.path.dirname(__file__), "..", "data"))
  58
  59 loader = Loader(_DATA_PREFIX)