Fix position tracking on reload in piper backed

src/calibre/gui2/tts2/manager.py

@@ -72,14 +72,14 @@ class Tracker:
             return self.queue[0].text
         return ''
 
-    def resume(self):
+    def resume(self, filler_char: str = ' '):
         self.last_pos = 0
         if self.queue:
             self.last_pos = self.queue[0].index_in_positions
             if self.queue[0].reached_offset:
                 o = self.queue[0].reached_offset
                 # make sure positions remain the same for word tracking
-                self.queue[0] = self.queue[0]._replace(text=(' ' * o) + self.queue[0].text[o:])
+                self.queue[0] = self.queue[0]._replace(text=(filler_char * o) + self.queue[0].text[o:])
         return self.current_text()
 
     def boundary_reached(self, start):
@@ -160,7 +160,7 @@ class TTSManager(QObject):
         yield rd
         if rd.is_speaking:
             if rd.needs_full_resume:
-                self.tts.say(self.tracker.resume())
+                self.tts.say(self.tracker.resume(self.tts.filler_char))
             else:
                 self.tts.resume()
 

src/calibre/gui2/tts2/piper.py

@@ -32,7 +32,7 @@ from qt.core import (
 from calibre.constants import cache_dir, is_debugging
 from calibre.gui2 import error_dialog
 from calibre.gui2.tts2.types import EngineSpecificSettings, Quality, TTSBackend, Voice, piper_cmdline, widget_parent
-from calibre.spell.break_iterator import split_into_sentences_for_tts
+from calibre.spell.break_iterator import PARAGRAPH_SEPARATOR, split_into_sentences_for_tts
 from calibre.utils.localization import canonicalize_lang, get_lang
 from calibre.utils.resources import get_path as P
 
@@ -156,6 +156,7 @@ def split_into_utterances(text: str, counter: count, lang: str = 'en'):
 class Piper(TTSBackend):
 
     engine_name: str = 'piper'
+    filler_char: str = PARAGRAPH_SEPARATOR
     _synthesis_done = pyqtSignal()
 
     def __init__(self, engine_name: str = '', parent: QObject|None = None):

src/calibre/gui2/tts2/types.py

@@ -269,6 +269,7 @@ class TTSBackend(QObject):
     available_voices: dict[str, tuple[Voice, ...]] = {}
     engine_name: str = ''
     default_output_module: str = ''
+    filler_char: str = ' '
 
     def __init__(self, engine_name: str = '', parent: QObject|None = None):
         super().__init__(parent)

src/calibre/spell/break_iterator.py

@@ -93,7 +93,10 @@ def split_long_sentences(sentence: str, offset: int, lang: str = 'en', limit: in
         yield offset + start_at, ' '.join(buf)
 
 
-def split_into_sentences_for_tts(text: str, lang: str = 'en', PARAGRAPH_SEPARATOR: str = '\u2029'):
+PARAGRAPH_SEPARATOR = '\u2029'
+
+
+def split_into_sentences_for_tts(text: str, lang: str = 'en', PARAGRAPH_SEPARATOR: str = PARAGRAPH_SEPARATOR):
     import re
     def sub(m):
         return PARAGRAPH_SEPARATOR + ' ' * (len(m.group()) - 1)