Source Code for Module zeroinstall.gtkui.icon

 1  """Loading icons.""" 
 2  # Copyright (C) 2009, Thomas Leonard 
 3  # See the README file for details, or visit http://0install.net. 
 4   
 5  from zeroinstall import _ 
 6  import gtk 
 7  from logging import warn 
 8  import math 
 9   
10 -def load_icon(icon_path, icon_width=None, icon_height=None): 
11          """Load icon from path. Icon MUST be in PNG format. 
12          @param icon_path: pathname of icon, or None to load nothing 
13          @return: a GdkPixbuf, or None on failure""" 
14          if not icon_path: 
15                  return None 
16   
17          def size_prepared_cb(loader, width, height): 
18                  dest_width = icon_width or width 
19                  dest_height = icon_height or height 
20   
21                  if dest_width == width and dest_height == height: 
22                          return 
23   
24                  ratio_width = float(dest_width) / width 
25                  ratio_height = float(dest_height) / height 
26                  ratio = min(ratio_width, ratio_height) 
27   
28                  # preserve original ration 
29                  if ratio_width != ratio: 
30                          dest_width = int(math.ceil(width * ratio)) 
31                  elif ratio_height != ratio: 
32                          dest_height = int(math.ceil(height * ratio)) 
33   
34                  loader.set_size(int(dest_width), int(dest_height)) 
35   
36          # Restrict icon formats to avoid attacks 
37          try: 
38                  loader = gtk.gdk.PixbufLoader('png') 
39                  if icon_width or icon_height: 
40                          loader.connect('size-prepared', size_prepared_cb) 
41                  try: 
42                          loader.write(open(icon_path).read()) 
43                  finally: 
44                          loader.close() 
45                  return loader.get_pixbuf() 
46          except Exception as ex: 
47                  warn(_("Failed to load cached PNG icon: %s") % ex) 
48                  return None 
49