Fix folder navigation and restyle navigation arrows

app/qt/image_processor.py

@@ -84,38 +84,38 @@ class QtImageProcessor:
 
     # image handling --------------------------------------------------------
 
-    def load_single_image(self, path: Path) -> None:
+    def load_single_image(self, path: Path, *, reset_collection: bool = True) -> Path:
         image = Image.open(path).convert("RGBA")
         self.orig_img = image
-        self.preview_paths = [path]
+        if reset_collection:
-        self.current_index = 0
+            self.preview_paths = [path]
+            self.current_index = 0
         self._build_preview()
-        if self.reset_exclusions_on_switch:
-            self.exclude_shapes = []
         self._rebuild_overlay()
+        return path
 
-    def load_folder(self, paths: Iterable[Path], start_index: int = 0) -> None:
+    def load_folder(self, paths: Iterable[Path], start_index: int = 0) -> Path:
         self.preview_paths = list(paths)
         if not self.preview_paths:
             raise ValueError("No images in folder.")
         self.current_index = max(0, min(start_index, len(self.preview_paths) - 1))
-        self._load_current()
+        return self._load_image_at_current()
 
-    def next_image(self) -> None:
+    def next_image(self) -> Path | None:
         if not self.preview_paths:
-            return
+            return None
         self.current_index = (self.current_index + 1) % len(self.preview_paths)
-        self._load_current()
+        return self._load_image_at_current()
 
-    def previous_image(self) -> None:
+    def previous_image(self) -> Path | None:
         if not self.preview_paths:
-            return
+            return None
         self.current_index = (self.current_index - 1) % len(self.preview_paths)
-        self._load_current()
+        return self._load_image_at_current()
 
-    def _load_current(self) -> None:
+    def _load_image_at_current(self) -> Path:
         path = self.preview_paths[self.current_index]
-        self.load_single_image(path)
+        return self.load_single_image(path, reset_collection=False)
 
     # preview/overlay -------------------------------------------------------
 

app/qt/main_window.py

@@ -672,9 +672,12 @@ class MainWindow(QtWidgets.QMainWindow, I18nMixin):
         layout.setHorizontalSpacing(16)
 
         self.prev_button = QtWidgets.QToolButton()
-        self.prev_button.setText("◀")
         self.prev_button.setCursor(QtCore.Qt.PointingHandCursor)
-        self.prev_button.setFixedSize(44, 44)
+        self.prev_button.setAutoRaise(True)
+        self.prev_button.setToolButtonStyle(QtCore.Qt.ToolButtonIconOnly)
+        self.prev_button.setIcon(self.style().standardIcon(QtWidgets.QStyle.SP_ArrowBack))
+        self.prev_button.setIconSize(QtCore.QSize(20, 20))
+        self.prev_button.setFixedSize(38, 38)
         self.prev_button.clicked.connect(lambda: self._invoke_action("show_previous_image"))
         layout.addWidget(self.prev_button, 0, 0, QtCore.Qt.AlignVCenter)
 
@@ -687,9 +690,12 @@ class MainWindow(QtWidgets.QMainWindow, I18nMixin):
         layout.addWidget(self.overlay_view, 0, 2)
 
         self.next_button = QtWidgets.QToolButton()
-        self.next_button.setText("▶")
         self.next_button.setCursor(QtCore.Qt.PointingHandCursor)
-        self.next_button.setFixedSize(44, 44)
+        self.next_button.setAutoRaise(True)
+        self.next_button.setToolButtonStyle(QtCore.Qt.ToolButtonIconOnly)
+        self.next_button.setIcon(self.style().standardIcon(QtWidgets.QStyle.SP_ArrowForward))
+        self.next_button.setIconSize(QtCore.QSize(20, 20))
+        self.next_button.setFixedSize(38, 38)
         self.next_button.clicked.connect(lambda: self._invoke_action("show_next_image"))
         layout.addWidget(self.next_button, 0, 3, QtCore.Qt.AlignVCenter)
         layout.setColumnStretch(1, 1)
@@ -742,11 +748,11 @@ class MainWindow(QtWidgets.QMainWindow, I18nMixin):
             return
         path = Path(path_str)
         try:
-            self.processor.load_single_image(path)
+            loaded_path = self.processor.load_single_image(path)
         except Exception as exc:  # pragma: no cover - user feedback
             QtWidgets.QMessageBox.warning(self, self._t("dialog.error_title"), str(exc))
             return
-        self._current_image_path = path
+        self._current_image_path = loaded_path
         if self.processor.reset_exclusions_on_switch:
             self.image_view.clear_shapes()
             self.processor.set_exclusions([])
@@ -765,19 +771,21 @@ class MainWindow(QtWidgets.QMainWindow, I18nMixin):
             QtWidgets.QMessageBox.information(self, self._t("dialog.info_title"), self._t("dialog.folder_empty"))
             return
         try:
-            self.processor.load_folder(paths)
+            loaded_path = self.processor.load_folder(paths)
         except ValueError as exc:
             QtWidgets.QMessageBox.information(self, self._t("dialog.info_title"), str(exc))
             return
-        self._current_image_path = paths[0]
+        self._current_image_path = loaded_path
         self._refresh_views()
 
     def show_previous_image(self) -> None:
         if not self.processor.preview_paths:
             QtWidgets.QMessageBox.information(self, self._t("dialog.info_title"), self._t("dialog.no_image_loaded"))
             return
-        self.processor.previous_image()
+        path = self.processor.previous_image()
-        self._current_image_path = self.processor.preview_paths[self.processor.current_index]
+        if path is None:
+            return
+        self._current_image_path = path
         if self.processor.reset_exclusions_on_switch:
             self.image_view.clear_shapes()
             self.processor.set_exclusions([])
@@ -787,8 +795,10 @@ class MainWindow(QtWidgets.QMainWindow, I18nMixin):
         if not self.processor.preview_paths:
             QtWidgets.QMessageBox.information(self, self._t("dialog.info_title"), self._t("dialog.no_image_loaded"))
             return
-        self.processor.next_image()
+        path = self.processor.next_image()
-        self._current_image_path = self.processor.preview_paths[self.processor.current_index]
+        if path is None:
+            return
+        self._current_image_path = path
         if self.processor.reset_exclusions_on_switch:
             self.image_view.clear_shapes()
             self.processor.set_exclusions([])
@@ -895,13 +905,8 @@ class MainWindow(QtWidgets.QMainWindow, I18nMixin):
         for control in self._slider_controls.values():
             control.apply_theme(colours)
 
-        style_button = (
+        self._style_nav_button(self.prev_button)
-            f"QToolButton {{ border-radius: 22px; background-color: {colours['panel_bg']}; "
+        self._style_nav_button(self.next_button)
-            f"border: 1px solid {colours['border']}; color: {colours['text']}; }}"
-            f"QToolButton:hover {{ background-color: {colours['accent_secondary']}; color: white; }}"
-        )
-        self.prev_button.setStyleSheet(style_button)
-        self.next_button.setStyleSheet(style_button)
 
         self.title_bar.apply_theme(colours)
 
@@ -917,6 +922,20 @@ class MainWindow(QtWidgets.QMainWindow, I18nMixin):
                 return self._t(title_key)
         return key
 
+    def _style_nav_button(self, button: QtWidgets.QToolButton) -> None:
+        colours = THEMES[self.current_theme]
+        button.setStyleSheet(
+            f"QToolButton {{ border-radius: 19px; background-color: {colours['panel_bg']}; "
+            f"border: 1px solid {colours['border']}; color: {colours['text']}; }}"
+            f"QToolButton:hover {{ background-color: {colours['accent_secondary']}; color: white; }}"
+        )
+        button.setIconSize(QtCore.QSize(20, 20))
+        if button is getattr(self, "prev_button", None):
+            button.setIcon(self.style().standardIcon(QtWidgets.QStyle.SP_ArrowBack))
+        elif button is getattr(self, "next_button", None):
+            button.setIcon(self.style().standardIcon(QtWidgets.QStyle.SP_ArrowForward))
+
+
     def _refresh_views(self) -> None:
         preview_pix = self.processor.preview_pixmap()
         overlay_pix = self.processor.overlay_pixmap()