Add preview button to voice mixer

CHANGELOG.md

@@ -1,4 +1,5 @@
 - Added `Insert chapter marker` button in text editor to insert chapter markers at the current cursor position.
+- Added `Preview` button in voice mixer to preview the voice mix with the selected settings.
 - Fixed `f-string: unmatched '['` error in Voice preview, mentioned in #14
-- Fixed the content before first chapter not being included in the output (added handling for initial content).
+- Fixed the issue with the content before first chapter not being included in the output.
 - Fixed m4b chapter generation opens CMD window in Windows.

abogen/gui.py

@@ -290,8 +290,8 @@ class InputBox(QLabel):
                 )
                 win.selected_book_path = file_path
                 win.open_book_file(
-                    file_path
-                )  # This will handle the dialog and setting file info
+                    file_path  # This will handle the dialog and setting file info
+                )
                 event.acceptProposedAction()
             else:
                 self.set_error("Please drop a .txt, .epub, or .pdf file.")
@@ -328,7 +328,7 @@ class TextboxDialog(QDialog):
         self.setWindowFlags(
             Qt.Window | Qt.WindowCloseButtonHint | Qt.WindowMaximizeButtonHint
         )
-        self.resize(600, 400)
+        self.resize(700, 500)
 
         layout = QVBoxLayout(self)
 
@@ -452,7 +452,7 @@ class TextboxDialog(QDialog):
     def insert_chapter_marker(self):
         # Insert a fixed chapter marker without prompting
         cursor = self.text_edit.textCursor()
-        cursor.insertText("<<CHAPTER_MARKER:Chapter Title>>")
+        cursor.insertText("<<CHAPTER_MARKER:Title>>")
         self.text_edit.setTextCursor(cursor)
         self.update_char_count()
 
@@ -1500,14 +1500,14 @@ class abogen(QWidget):
             # Build voice formula string
             components = [f"{name}*{weight}" for name, weight in self.mixed_voice_state]
             voice = " + ".join(filter(None, components))
-            # determine language: use profile setting if available, else first voice code
+            # determine language: use profile setting, else explicit mixer selection, else fallback to first voice code
             if self.selected_profile_name:
                 from voice_profiles import load_profiles
 
                 entry = load_profiles().get(self.selected_profile_name, {})
                 lang = entry.get("language")
             else:
-                lang = None
+                lang = self.selected_lang
             if not lang and self.mixed_voice_state:
                 lang = (
                     self.mixed_voice_state[0][0][0]
@@ -2138,4 +2138,3 @@ class abogen(QWidget):
                 "Setting Saved",
                 f"Maximum words per subtitle set to {value}.",
             )
-

abogen/voice_formula_gui.py

@@ -47,7 +47,7 @@ VOICE_MIXER_WIDTH = 100
 SLIDER_WIDTH = 32
 MIN_WINDOW_WIDTH = 600
 MIN_WINDOW_HEIGHT = 400
-INITIAL_WINDOW_WIDTH = 1000
+INITIAL_WINDOW_WIDTH = 1200
 INITIAL_WINDOW_HEIGHT = 500
 
 # Language options for the language selector loaded from constants
@@ -413,6 +413,11 @@ class VoiceFormulaDialog(QDialog):
             self.language_combo.setCurrentIndex(idx)
         self.language_combo.currentIndexChanged.connect(self.mark_profile_modified)
         header_row.addWidget(self.language_combo)
+        # Preview current voice mix using main window's preview
+        self.btn_preview_mix = QPushButton("Preview", self)
+        self.btn_preview_mix.setToolTip("Preview current voice mix")
+        self.btn_preview_mix.clicked.connect(self.preview_current_mix)
+        header_row.addWidget(self.btn_preview_mix)
         mixer_layout.addLayout(header_row)
 
         # Error message
@@ -708,6 +713,8 @@ class VoiceFormulaDialog(QDialog):
         ]
 
         total = sum(w for _, w in selected)
+        # disable Preview if no voices selected
+        self.btn_preview_mix.setEnabled(total > 0)
 
         if total > 0:
             self.error_label.hide()
@@ -1338,3 +1345,37 @@ class VoiceFormulaDialog(QDialog):
                 else:
                     item.setBackground(QColor("white"))
         self.update_profile_save_buttons()
+
+    def preview_current_mix(self):
+        # Disable preview until playback completes
+        self.btn_preview_mix.setEnabled(False)
+        self.btn_preview_mix.setText("Loading...")
+        parent = self.parent()
+        if parent and hasattr(parent, "preview_voice"):
+            # Apply mixed voices and selected language
+            parent.mixed_voice_state = self.get_selected_voices()
+            parent.selected_profile_name = None
+            lang = self.language_combo.currentData()
+            parent.selected_lang = lang
+            parent.subtitle_combo.setEnabled(
+                lang in SUPPORTED_LANGUAGES_FOR_SUBTITLE_GENERATION
+            )
+            # Reset start flag and trigger preview
+            self._started = False
+            parent.preview_voice()
+            # Poll preview_playing: wait for start then end
+            self._preview_poll_timer = QTimer(self)
+            self._preview_poll_timer.timeout.connect(self._check_preview_done)
+            self._preview_poll_timer.start(200)
+
+    def _check_preview_done(self):
+        parent = self.parent()
+        if parent and hasattr(parent, "preview_playing"):
+            # Mark when playback starts
+            if parent.preview_playing:
+                self._started = True
+            # Once started and then stopped, re-enable
+            elif getattr(self, "_started", False):
+                self.btn_preview_mix.setEnabled(True)
+                self.btn_preview_mix.setText("Preview")
+                self._preview_poll_timer.stop()