Guess bold and italic properties for unknown glyphs based on all known glyphs from the same word.

pixelocr/document.py

@@ -71,7 +71,7 @@ class Document(object):
         try:
             glyph_data = self.glyphdb[glyph]
         except KeyError:
-            text, bold, italic = self.ui.ask_for_help(glyph, self.last_style.bold, self.last_style.italic)
+            text, bold, italic = self.ui.ask_for_help(glyph, glyph.word.guess_bold(), glyph.word.guess_italic())
             glyph_data = self.glyphdb.add_glyph(glyph, text, bold, italic)
         self.last_style = glyph_data.style
         return glyph_data

pixelocr/page.py

@@ -269,6 +269,29 @@ class Word(PageObject):
         image = line.image[:, beginning.left:end.right]
         super().__init__(line.document, image)
 
+    def guess_bold(self):
+        return self._guess('bold')
+
+    def guess_italic(self):
+        return self._guess('italic')
+
+    def _guess(self, attr):
+        known_glyph_info = self._known_glyph_info()
+        if not known_glyph_info:
+            return None
+        total = sum(getattr(glyph_info.style, attr) for glyph_info in self._known_glyph_info())
+        avg = total / len(self.glyphs)
+        return avg > 0.5
+
+    @collect_iterable
+    def _known_glyph_info(self):
+        glyphdb = self.document.glyphdb
+        for glyph in self.glyphs:
+            try:
+                yield glyphdb[glyph]
+            except KeyError:
+                pass
+
 
 class Glyph(PageObject):
     word = None