1) fix problem where new covers are not sent as thumbnails even if the options ask for it.

2) permit not respecting aspect ratio when generating cover thumbnails

src/calibre/devices/interface.py

@@ -35,6 +35,16 @@ class DevicePlugin(Plugin):
 
     #: Height for thumbnails on the device
     THUMBNAIL_HEIGHT = 68
+    #: Width for thumbnails on the device. Setting this will force thumbnails
+    #: to this size, not preserving aspect ratio. If it is not set, then
+    #: the aspect ratio will be preserved and the thumbnail will be no higher
+    #: than THUMBNAIL_HEIGHT
+    # THUMBNAIL_WIDTH = 68
+
+    #: Set this to True if the device supports updating cover thumbnails during
+    #: sync_booklists. Setting it to true will ask device.py to refresh the
+    #: cover thumbnails during book matching
+    WANTS_UPDATED_THUMBNAILS = False
 
     #: Whether the metadata on books can be set via the GUI.
     CAN_SET_METADATA = ['title', 'authors', 'collections']

src/calibre/devices/prs505/driver.py

@@ -81,12 +81,19 @@ class PRS505(USBMS):
                 _('Set this option to have separate book covers uploaded '
                   'every time you connect your device. Unset this option if '
                   'you have so many books on the reader that performance is '
-                  'unacceptable.')
+                  'unacceptable.'),
+            _('Preserve cover aspect ratio when building thumbnails') +
+                ':::' +
+                _('Set this option if you want the cover thumbnails to have '
+                  'the same aspect ratio (width to height) as the cover. '
+                  'Unset it if you want the thumbnail to be the maximum size, '
+                  'ignoring aspect ratio.')
     ]
     EXTRA_CUSTOMIZATION_DEFAULT = [
                 ', '.join(['series', 'tags']),
                 False,
-                False
+                False,
+                True
     ]
 
     OPT_COLLECTIONS    = 0
@@ -96,7 +103,7 @@ class PRS505(USBMS):
     plugboard = None
     plugboard_func = None
 
-    THUMBNAIL_HEIGHT = 200
+    THUMBNAIL_HEIGHT = 217
 
     MAX_PATH_LEN = 201 # 250 - (max(len(CACHE_THUMBNAIL), len(MEDIA_THUMBNAIL)) +
                        # len('main_thumbnail.jpg') + 1)
@@ -138,6 +145,13 @@ class PRS505(USBMS):
             if not write_cache(self._card_b_prefix):
                 self._card_b_prefix = None
         self.booklist_class.rebuild_collections = self.rebuild_collections
+        # Set the thumbnail width to the theoretical max if the user has asked
+        # that we do not preserve aspect ratio
+        if not self.settings().extra_customization[3]:
+            self.THUMBNAIL_WIDTH = 168
+        # Set CAN_UPDATE_THUMBNAILS if the user has asked that thumbnails be
+        # updated on every connect
+        self.WANTS_UPDATED_THUMBNAILS = self.settings().extra_customization[2]
 
     def get_device_information(self, end_session=True):
         return (self.gui_name, '', '', '')

src/calibre/gui2/device.py

@@ -871,6 +871,16 @@ class DeviceMixin(object): # {{{
             self.send_by_mail(to, fmts, delete)
 
     def cover_to_thumbnail(self, data):
+        if self.device_manager.device and \
+                hasattr(self.device_manager.device, 'THUMBNAIL_WIDTH'):
+            try:
+                return thumbnail(data,
+                                 self.device_manager.device.THUMBNAIL_WIDTH,
+                                 self.device_manager.device.THUMBNAIL_HEIGHT,
+                                 preserve_aspect_ratio=False)
+            except:
+                pass
+            return
         ht = self.device_manager.device.THUMBNAIL_HEIGHT \
                 if self.device_manager else DevicePlugin.THUMBNAIL_HEIGHT
         try:
@@ -1272,6 +1282,8 @@ class DeviceMixin(object): # {{{
             x = x.lower() if x else ''
             return string_pat.sub('', x)
 
+        update_metadata = prefs['manage_device_metadata'] == 'on_connect'
+
         # Force a reset if the caches are not initialized
         if reset or not hasattr(self, 'db_book_title_cache'):
             # Build a cache (map) of the library, so the search isn't On**2
@@ -1284,8 +1296,13 @@ class DeviceMixin(object): # {{{
             except:
                 return False
 
+            get_covers = False
+            if update_metadata and self.device_manager.is_device_connected:
+                if self.device_manager.device.WANTS_UPDATED_THUMBNAILS:
+                    get_covers = True
+
             for id in db.data.iterallids():
-                mi = db.get_metadata(id, index_is_id=True)
+                mi = db.get_metadata(id, index_is_id=True, get_cover=get_covers)
                 title = clean_string(mi.title)
                 if title not in db_book_title_cache:
                     db_book_title_cache[title] = \
@@ -1311,7 +1328,6 @@ class DeviceMixin(object): # {{{
         # the application_id to the db_id of the matching book. This value
         # will be used by books_on_device to indicate matches.
 
-        update_metadata = prefs['manage_device_metadata'] == 'on_connect'
         for booklist in booklists:
             for book in booklist:
                 book.in_library = None
@@ -1382,6 +1398,12 @@ class DeviceMixin(object): # {{{
 
         if update_metadata:
             if self.device_manager.is_device_connected:
+                if self.device_manager.device.CAN_UPDATE_THUMBNAILS:
+                    for blist in booklists:
+                        for book in blist:
+                            if book.cover and os.access(book.cover, os.R_OK):
+                                book.thumbnail = \
+                                    self.cover_to_thumbnail(open(book.cover, 'rb').read())
                 plugboards = self.library_view.model().db.prefs.get('plugboards', {})
                 self.device_manager.sync_booklists(
                                     Dispatcher(self.metadata_synced), booklists,

src/calibre/utils/magick/draw.py

@@ -72,11 +72,18 @@ def save_cover_data_to(data, path, bgcolor='#ffffff', resize_to=None,
                 f.write(data)
     return ret
 
-def thumbnail(data, width=120, height=120, bgcolor='#ffffff', fmt='jpg'):
+def thumbnail(data, width=120, height=120, bgcolor='#ffffff', fmt='jpg',
+              preserve_aspect_ratio=True):
     img = Image()
     img.load(data)
     owidth, oheight = img.size
-    scaled, nwidth, nheight = fit_image(owidth, oheight, width, height)
+    if not preserve_aspect_ratio:
+        scaled = owidth > width or oheight > height
+        nwidth = width
+        nheight = height
+    else:
+        scaled, nwidth, nheight = fit_image(owidth, oheight, width, height)
+    print 'in thumbnail', scaled, nwidth, nheight
     if scaled:
         img.size = (nwidth, nheight)
     canvas = create_canvas(img.size[0], img.size[1], bgcolor)