E-book viewer: Add workaround for Qt embedded font bug (at least for ebooks that put all their css in .css files, such as ebooks generated by calibre)

src/calibre/ebooks/oeb/iterator/book.py

@@ -22,7 +22,6 @@ from calibre.utils.logging import default_log
 from calibre import (guess_type, prepare_string_for_xml,
         xml_replace_entities)
 from calibre.ebooks.oeb.transforms.cover import CoverManager
-
 from calibre.ebooks.oeb.iterator.spine import (SpineItem, create_indexing_data)
 from calibre.ebooks.oeb.iterator.bookmarks import BookmarksMixin
 
@@ -76,7 +75,8 @@ class EbookIterator(BookmarksMixin):
                     return i
 
     def __enter__(self, processed=False, only_input_plugin=False,
-            run_char_count=True, read_anchor_map=True):
+            run_char_count=True, read_anchor_map=True,
+            extract_embedded_fonts_for_qt=False):
         ''' Convert an ebook file into an exploded OEB book suitable for
         display in viewers/preprocessing etc. '''
 
@@ -174,6 +174,16 @@ class EbookIterator(BookmarksMixin):
 
         self.read_bookmarks()
 
+        if extract_embedded_fonts_for_qt:
+            from calibre.ebooks.oeb.iterator.extract_fonts import extract_fonts
+            try:
+                extract_fonts(self.opf, self.log)
+            except:
+                ol = self.log.filter_level
+                self.log.filter_level = self.log.DEBUG
+                self.log.exception('Failed to extract fonts')
+                self.log.filter_level = ol
+
         return self
 
     def __exit__(self, *args):

src/calibre/ebooks/oeb/iterator/extract_fonts.py

@@ -0,0 +1,100 @@
+#!/usr/bin/env python
+# vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:fdm=marker:ai
+from __future__ import (unicode_literals, division, absolute_import,
+                        print_function)
+
+__license__   = 'GPL v3'
+__copyright__ = '2012, Kovid Goyal <kovid at kovidgoyal.net>'
+__docformat__ = 'restructuredtext en'
+
+import re, os, logging
+from functools import partial
+from future_builtins import map
+
+class FamilyMap(dict):
+
+    def __init__(self, log):
+        dict.__init__(self)
+        self.replace_map = {}
+        self.added_fonts = set()
+        self.log = log
+
+    def __call__(self, basedir, match):
+        self.read_font_fule(basedir, match.group())
+        return b''
+
+    def finalize(self):
+        if self.replace_map:
+            self.pat = re.compile(br'(font-family.*?)(' +
+                    b'|'.join(self.replace_map.iterkeys())+b')', re.I)
+
+    def replace_font_families(self, raw):
+        if self.replace_map:
+            def sub(m):
+                k = m.group(2).lower()
+                for q, val in self.replace_map.iteritems():
+                    if q.lower() == k.lower():
+                        return m.group().replace(m.group(2), val)
+                return m.group()
+
+            return self.pat.sub(sub, raw)
+
+    def read_font_fule(self, basedir, css):
+        from PyQt4.Qt import QFontDatabase
+        import cssutils
+        cssutils.log.setLevel(logging.ERROR)
+        try:
+            sheet = cssutils.parseString(css)
+        except:
+            return
+        for rule in sheet.cssRules:
+            try:
+                s = rule.style
+                src = s.getProperty('src').propertyValue[0].uri
+                font_family = s.getProperty('font-family').propertyValue[0].value
+            except:
+                continue
+            if not src or not font_family:
+                continue
+            font_file = os.path.normcase(os.path.abspath(os.path.join(basedir,
+                src)))
+            if font_file not in self.added_fonts:
+                self.added_fonts.add(font_file)
+                if os.path.exists(font_file):
+                    with open(font_file, 'rb') as f:
+                        idx = QFontDatabase.addApplicationFontFromData(f.read())
+                    if idx > -1:
+                        family = map(unicode,
+                            QFontDatabase.applicationFontFamilies(idx)).next()
+                        self.log('Extracted embedded font:', family, 'from',
+                                os.path.basename(font_file))
+                        if (family and family != font_family and
+                                family not in self.replace_map):
+                            self.log('Replacing font family value:',
+                                    font_family, 'with', family)
+                            self.replace_map[font_family.encode('utf-8')] = \
+                                    family.encode('utf-8')
+
+def extract_fonts(opf, log):
+    css_files = {}
+    font_family_map = FamilyMap(log)
+    pat = re.compile(br'^\s*@font-face\s*{[^}]+}', re.M)
+
+    for item in opf.manifest:
+        if item.mime_type and item.mime_type.lower() in {
+                'text/css', 'text/x-oeb1-css', 'text/x-oeb-css'}:
+            try:
+                with open(item.path, 'rb') as f:
+                    raw = f.read()
+            except EnvironmentError:
+                continue
+            css_files[item.path] = pat.sub(partial(font_family_map,
+                os.path.dirname(item.path)), raw)
+
+    font_family_map.finalize()
+
+    for path, raw in css_files.iteritems():
+        with open(path, 'wb') as f:
+            nraw = font_family_map.replace_font_families(raw)
+            f.write(nraw)
+

src/calibre/gui2/viewer/main.py

@@ -963,7 +963,8 @@ class EbookViewer(MainWindow, Ui_EbookViewer):
             self.iterator.__exit__()
         self.iterator = EbookIterator(pathtoebook)
         self.open_progress_indicator(_('Loading ebook...'))
-        worker = Worker(target=self.iterator.__enter__)
+        worker = Worker(target=partial(self.iterator.__enter__,
+            extract_embedded_fonts_for_qt=True))
         worker.start()
         while worker.isAlive():
             worker.join(0.1)