Restrict maximum icon size with --max-icon-size

By using the --max-icon-size option any icons that are larger than the
requested icon size get discarded. This is useful for at least Fvwm,
where the menus can hold icons of any size, with no option to resize to
a maximum size, making for some funny looking menus.

This adds a new dependency on the Pillow library, which is only loaded
if the --max-icon-size option is used.

src/xdgmenumaker

@@ -35,6 +35,7 @@ iconsize = 16
 desktop = False
 submenu = True
 pekwmdynamic = False
+max_icon_size = False
 
 # the following line gets changed by the Makefile. If it is set to
 # 'not_set' it looks in the currect directory tree for the .directory
@@ -167,10 +168,12 @@ def main(argv):
     global iconsize
     global submenu
     global pekwmdynamic
+    global max_icon_size
     try:
         opts, args = getopt.getopt(argv, "hins:f:", ["help", "icons",
                                                      "no-submenu",
                                                      "pekwm-dynamic",
+                                                     "max-icon-size",
                                                      "size=",
                                                      "format="])
     except getopt.GetoptError:
@@ -192,6 +195,20 @@ def main(argv):
             submenu = False
         elif opt in ("--pekwm-dynamic",):
             pekwmdynamic = True
+        elif opt in ("--max-icon-size",):
+            try:
+                # Pillow is optional and loaded only if we want to restrict the
+                # icon sizes (useful for Fvwm). Yeah, I know it's not a good
+                # idea to load a module in here, but I really don't want to
+                # load it by default at the top. It would make xdgmenumaker a
+                # bit slower to run even if it is not needed. This way it only
+                # slows down when it is actually needed.
+                global Image
+                from PIL import Image
+                max_icon_size = True
+            except ImportError:
+                usage()
+                sys.exit('ERROR: --max-icon-size requires Pillow')
         elif opt in ("-f", "--format"):
             desktop = arg
     if not desktop:
@@ -251,22 +268,39 @@ def icon_strip(icon):
         icon = icon.replace('.xpm', '')
     return icon
 
+def icon_max_size(icon):
+    # Checks if the icon size is bigger than the requested size and discards
+    # the icon if it is, only allowing sizes smaller or equal to the requested
+    # size
+    try:
+        img = Image.open(icon)
+    except:
+        # if there is any error reading the icon, just discard it
+        return None
+    if img.size[0] <= iconsize:
+        return icon
+    else:
+        return None
 
 def icon_full_path(icon):
     # If the icon path is absolute and exists, leave it alone.
     # This takes care of software that has its own icons stored
     # in non-standard directories
     if os.path.exists(icon):
-        return icon
+        if max_icon_size:
+            return icon_max_size(icon)
+        else:
+            return None
     else:
         icon = icon_strip(icon)
         icon_theme = gtk.icon_theme_get_default()
         icon = icon_theme.lookup_icon(icon, iconsize, gtk.ICON_LOOKUP_NO_SVG)
         if icon:
             icon = icon.get_filename()
+            if max_icon_size:
+                icon = icon_max_size(icon)
         return icon
 
-
 def get_entry_info(desktopfile, ico_paths=True):
     de = dentry.DesktopEntry(filename=desktopfile)