Attempt to decrease dectalk lag. Hoping you don't have to send settings over every time you want it to say something.

src/fenrirscreenreader/speechDriver/dectalkUsbDriver.py

@@ -27,6 +27,7 @@ class driver(dectalkDriver.driver):
     def initialize(self, environment):
         self.env = environment
         self._is_initialized = False
+        self._reset_setting_cache()
         self.usb_device = None
         self.usb_core = None
         self.usb_util = None
@@ -187,7 +188,7 @@ class driver(dectalkDriver.driver):
     def _write_bytes(self, data, description="data", cancel_generation=None):
         if description == "speech" and cancel_generation is None:
             cancel_generation = self._get_speech_cancel_generation()
-        self._write_endpoint(
+        return self._write_endpoint(
             self.speech_endpoint,
             data,
             description,
@@ -203,12 +204,12 @@ class driver(dectalkDriver.driver):
         cancel_generation=None,
     ):
         if not data:
-            return
+            return False
         if write_lock is None:
             write_lock = self.lock
         with write_lock:
             if self.usb_device is None:
-                return
+                return False
             try:
                 total_written = 0
                 while total_written < len(data):
@@ -220,7 +221,7 @@ class driver(dectalkDriver.driver):
                             debug.DebugLevel.INFO,
                             on_any_level=True,
                         )
-                        return
+                        return False
                     chunk = data[
                         total_written : total_written + self.packet_size
                     ]
@@ -243,12 +244,14 @@ class driver(dectalkDriver.driver):
                     debug.DebugLevel.INFO,
                     on_any_level=True,
                 )
+                return True
             except (self.usb_core.USBError, OSError) as error:
                 self._debug(
                     f"DECtalk USB write failed: {error}",
                     debug.DebugLevel.ERROR,
                     on_any_level=True,
                 )
+                return False
 
     def _advance_speech_cancel_generation(self):
         with self._speech_cancel_lock:

src/fenrirscreenreader/speechDriver/hardwareSerialDriver.py

@@ -38,10 +38,12 @@ class hardware_serial_driver(speech_driver):
         self.lock = threading.Lock()
         self.worker_thread = None
         self._stop_worker = False
+        self._setting_cache = {}
 
     def initialize(self, environment):
         self.env = environment
         self._is_initialized = False
+        self._reset_setting_cache()
         settings_manager = self.env["runtime"]["SettingsManager"]
         self.device = self._clean_device_setting(
             settings_manager.get_setting("speech", "hardware_device")
@@ -115,21 +117,30 @@ class hardware_serial_driver(speech_driver):
             return
         if not isinstance(rate, float):
             return
-        self._write_bytes(self._rate_command(rate), "rate")
+        self._write_setting_command("rate", self._rate_command(rate))
 
     def set_pitch(self, pitch):
         if not self._is_initialized:
             return
         if not isinstance(pitch, float):
             return
-        self._write_bytes(self._pitch_command(pitch), "pitch")
+        self._write_setting_command("pitch", self._pitch_command(pitch))
 
     def set_volume(self, volume):
         if not self._is_initialized:
             return
         if not isinstance(volume, float):
             return
-        self._write_bytes(self._volume_command(volume), "volume")
+        self._write_setting_command("volume", self._volume_command(volume))
+
+    def _reset_setting_cache(self):
+        self._setting_cache = {}
+
+    def _write_setting_command(self, setting, command):
+        if self._setting_cache.get(setting) == command:
+            return
+        if self._write_bytes(command, setting):
+            self._setting_cache[setting] = command
 
     def _worker(self):
         while not self._stop_worker:
@@ -223,10 +234,10 @@ class hardware_serial_driver(speech_driver):
 
     def _write_bytes(self, data, description="data"):
         if not data:
-            return
+            return False
         with self.lock:
             if self.serial_port is None:
-                return
+                return False
             try:
                 total_written = 0
                 while total_written < len(data):
@@ -243,12 +254,14 @@ class hardware_serial_driver(speech_driver):
                     debug.DebugLevel.INFO,
                     on_any_level=True,
                 )
+                return True
             except OSError as error:
                 self._debug(
                     f"Hardware speech write failed: {error}",
                     debug.DebugLevel.ERROR,
                     on_any_level=True,
                 )
+                return False
 
     def _termios_baud_rate(self, baud_rate):
         baud_name = f"B{baud_rate}"