Refactor ThemeManager:

- Improve thread safety with lock
- Keep 1 reference to manager
- Remove all imports the manager (except 1)
- Added logging if manager is not available, or themes are not found
- This fixes a freeze in Windows on some systems during the launch of OpenShot, related to oleaut32.dll.

src/classes/app.py

@@ -153,7 +153,7 @@ def __init__(self, *args, **kwargs):
 
         # Instantiate Theme Manager (Singleton)
         from themes.manager import ThemeManager
-        ThemeManager(self)
+        self.theme_manager = ThemeManager(self)
 
     def show_environment(self, info, openshot):
         log = self.log
@@ -256,9 +256,8 @@ def gui(self):
         self.window = MainWindow()
 
         # Instantiate Theme Manager (Singleton)
-        from themes.manager import ThemeManager, ThemeName
-        theme_enum = ThemeName.find_by_name(self.settings.get("theme"))
-        theme = ThemeManager().apply_theme(theme_enum)
+        theme_name = self.settings.get("theme")
+        theme = self.theme_manager.apply_theme(theme_name)
 
         # Update theme in settings
         self.settings.set("theme", theme.name)

src/themes/base.py

@@ -34,7 +34,6 @@
 
 from classes import ui_util
 from classes.info import PATH
-from themes.manager import ThemeManager
 
 
 class BaseTheme:
@@ -150,26 +149,25 @@ def set_toolbar_buttons(self, toolbar, icon_size=24, settings=None):
                 if button_stylesheet:
                     button.setStyleSheet(button_stylesheet)
 
-
     def apply_theme(self):
-        # Get initial style and palette
-        manager = ThemeManager()
-
         # Apply the stylesheet to the entire application
-        if manager.original_style:
-            self.app.setStyle(manager.original_style)
-        if manager.original_palette:
-            self.app.setPalette(manager.original_palette)
+        from classes import info
+        from classes.logger import log
+        from PyQt5.QtGui import QFont, QFontDatabase
+
+        if not self.app.theme_manager:
+            log.warning("ThemeManager not initialized yet. Skip applying a theme.")
+
+        if self.app.theme_manager.original_style:
+            self.app.setStyle(self.app.theme_manager.original_style)
+        if self.app.theme_manager.original_palette:
+            self.app.setPalette(self.app.theme_manager.original_palette)
         self.app.setStyleSheet(self.style_sheet)
 
         # Hide main window status bar
         if hasattr(self.app, "window") and hasattr(self.app.window, "statusBar"):
             self.app.window.statusBar.hide()
 
-        from classes import info
-        from classes.logger import log
-        from PyQt5.QtGui import QFont, QFontDatabase
-
         # Load embedded font
         font_path = os.path.join(info.IMAGES_PATH, "fonts", "Ubuntu-R.ttf")
         if os.path.exists(font_path):

src/themes/manager.py

@@ -25,6 +25,7 @@
  along with OpenShot Library.  If not, see <http://www.gnu.org/licenses/>.
  """
 
+import threading
 from enum import Enum
 
 
@@ -51,31 +52,36 @@ def find_by_name(name):
 class ThemeManager:
     """Singleton Theme Manager class, used to easily switch between UI themes"""
     _instance = None
+    _lock = threading.Lock()
 
     def __new__(cls, app=None):
         """Override new method, so the same instance is always returned (i.e. singleton)"""
         if cls._instance is None:
-            cls._instance = super(ThemeManager, cls).__new__(cls)
-            cls._instance.app = app
-            cls._instance.original_style = app.style().objectName() if app else None
-            cls._instance.original_palette = app.palette() if app else None
-            cls._instance.current_theme = None
+            with cls._lock:
+                if cls._instance is None:
+                    cls._instance = super(ThemeManager, cls).__new__(cls)
+                    cls._instance.app = app
+                    cls._instance.original_style = app.style().objectName() if app else None
+                    cls._instance.original_palette = app.palette() if app else None
+                    cls._instance.current_theme = None
         return cls._instance
 
-    def apply_theme(self, theme_name):
+    def apply_theme(self, name):
         """Apply a new UI theme. Expects a ThemeName ENUM as the arg."""
-        if theme_name == ThemeName.HUMANITY_DARK:
+        theme_enum = ThemeName.find_by_name(name)
+
+        if theme_enum == ThemeName.HUMANITY_DARK:
             from themes.humanity.theme import HumanityDarkTheme
             self.current_theme = HumanityDarkTheme(self.app)
-        elif theme_name == ThemeName.RETRO:
+        elif theme_enum == ThemeName.RETRO:
             from themes.humanity.theme import Retro
             self.current_theme = Retro(self.app)
-        elif theme_name == ThemeName.COSMIC:
+        elif theme_enum == ThemeName.COSMIC:
             from themes.cosmic.theme import CosmicTheme
             self.current_theme = CosmicTheme(self.app)
 
         # Set name on theme instance
-        self.current_theme.name = theme_name.value
+        self.current_theme.name = theme_enum.value
 
         # Apply theme
         self.current_theme.apply_theme()

src/windows/main_window.py

@@ -1134,10 +1134,10 @@ def onPlayCallback(self):
         """Handle when playback is started"""
         # Set icon on Play button
         if self.initialized:
-            from themes.manager import ThemeManager
-            theme = ThemeManager().get_current_theme()
-            if theme:
-                theme.togglePlayIcon(True)
+            if get_app().theme_manager:
+                theme = get_app().theme_manager.get_current_theme()
+                if theme:
+                    theme.togglePlayIcon(True)
 
     def onPauseCallback(self):
         """Handle when playback is paused"""
@@ -1146,10 +1146,10 @@ def onPauseCallback(self):
 
         # Set icon on Pause button
         if self.initialized:
-            from themes.manager import ThemeManager
-            theme = ThemeManager().get_current_theme()
-            if theme:
-                theme.togglePlayIcon(False)
+            if get_app().theme_manager:
+                theme = get_app().theme_manager.get_current_theme()
+                if theme:
+                    theme.togglePlayIcon(False)
 
     def actionSaveFrame_trigger(self, checked=True):
         log.info("actionSaveFrame_trigger")
@@ -2992,19 +2992,22 @@ def foundCurrentVersion(self, version):
             # Add toolbar button for non-cosmic dusk themes
             # Cosmic dusk has a hidden toolbar button which is made visible
             # by the setVisible() call above this
-            from themes.manager import ThemeManager, ThemeName
-            theme = ThemeManager().get_current_theme()
-            if theme and theme.name != ThemeName.COSMIC.value:
-                # Add spacer and 'New Version Available' toolbar button (default hidden)
-                spacer = QWidget(self)
-                spacer.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Preferred)
-                self.toolBar.addWidget(spacer)
-
-                # Add update available button (with icon and text)
-                updateButton = QToolButton(self)
-                updateButton.setDefaultAction(self.actionUpdate)
-                updateButton.setToolButtonStyle(Qt.ToolButtonTextBesideIcon)
-                self.toolBar.addWidget(updateButton)
+            if get_app().theme_manager:
+                from themes.manager import ThemeName
+                theme = get_app().theme_manager.get_current_theme()
+                if theme and theme.name != ThemeName.COSMIC.value:
+                    # Add spacer and 'New Version Available' toolbar button (default hidden)
+                    spacer = QWidget(self)
+                    spacer.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Preferred)
+                    self.toolBar.addWidget(spacer)
+
+                    # Add update available button (with icon and text)
+                    updateButton = QToolButton(self)
+                    updateButton.setDefaultAction(self.actionUpdate)
+                    updateButton.setToolButtonStyle(Qt.ToolButtonTextBesideIcon)
+                    self.toolBar.addWidget(updateButton)
+            else:
+                log.warning("No ThemeManager loaded yet. Skip update available button.")
 
         # Initialize sentry exception tracing (now that we know the current version)
         from classes import sentry

src/windows/preferences.py

@@ -566,9 +566,8 @@ def dropdown_index_changed(self, widget, param, index):
 
         if param["setting"] == "theme":
             # Apply selected theme to UI
-            from themes.manager import ThemeManager, ThemeName
-            theme_enum = ThemeName.find_by_name(value)
-            ThemeManager().apply_theme(theme_enum)
+            if get_app().theme_manager:
+                get_app().theme_manager.apply_theme(value)
 
         # Check for restart
         self.check_for_restart(param)

src/windows/video_widget.py

@@ -44,7 +44,6 @@
 from classes.logger import log
 from classes.app import get_app
 from classes.query import Clip, Effect
-from themes.manager import ThemeManager
 
 
 class VideoWidget(QWidget, updates.UpdateInterface):
@@ -331,11 +330,15 @@ def paintEvent(self, event, *args):
             True)
 
         # Get theme colors (if any)
-        theme = ThemeManager().get_current_theme()
-        if not theme:
-            return
-        background_color = theme.get_color(".video_widget", "background-color")
-        painter.fillRect(event.rect(), background_color)
+        if get_app().theme_manager:
+            theme = get_app().theme_manager.get_current_theme()
+            if not theme:
+                log.warning("No theme loaded yet. Skip rendering video preview widget.")
+                return
+            background_color = theme.get_color(".video_widget", "background-color")
+            painter.fillRect(event.rect(), background_color)
+        else:
+            log.warning("No ThemeManager loaded yet. Skip rendering video preview widget.")
 
         # Find centered viewport
         viewport_rect = self.centeredViewport(self.width(), self.height())

src/windows/views/properties_tableview.py

@@ -49,7 +49,6 @@
 
 from windows.models.properties_model import PropertiesModel
 from windows.color_picker import ColorPicker
-from themes.manager import ThemeManager
 from .menu import StyledContextMenu
 
 import openshot
@@ -109,11 +108,15 @@ def paint(self, painter, option, index):
             value_percent = 0.0
 
         # Get theme colors
-        theme = ThemeManager().get_current_theme()
-        if not theme:
-            return
-        foreground_color = theme.get_color(".property_value", "foreground-color")
-        background_color = theme.get_color(".property_value", "background-color")
+        if get_app().theme_manager:
+            theme = get_app().theme_manager.get_current_theme()
+            if not theme:
+                log.warning("No theme loaded yet. Skip rendering properties widget.")
+                return
+            foreground_color = theme.get_color(".property_value", "foreground-color")
+            background_color = theme.get_color(".property_value", "background-color")
+        else:
+            log.warning("No ThemeManager loaded yet. Skip rendering properties widget.")
 
         # set background color
         painter.setPen(QPen(Qt.NoPen))

src/windows/views/zoom_slider.py

@@ -38,7 +38,7 @@
 from classes import updates
 from classes.app import get_app
 from classes.query import Clip, Track, Transition, Marker
-from themes.manager import ThemeManager
+from classes.logger import log
 
 
 class ZoomSlider(QWidget, updates.UpdateInterface):
@@ -108,10 +108,14 @@ def paintEvent(self, event, *args):
         event.accept()
 
         # Get theme colors
-        theme = ThemeManager().get_current_theme()
-        if not theme:
-            return
-        playhead_color = theme.get_color(".zoom_slider_playhead", "background-color")
+        if get_app().theme_manager:
+            theme = get_app().theme_manager.get_current_theme()
+            if not theme:
+                log.warning("No theme loaded yet. Skip rendering zoom slider widget.")
+                return
+            playhead_color = theme.get_color(".zoom_slider_playhead", "background-color")
+        else:
+            log.warning("No ThemeManager loaded yet. Skip rendering zoom slider widget.")
 
         # Paint timeline preview on QWidget
         painter = QPainter(self)