feat: show crop bar with vertical lines when random portrait is enabled

When the random portrait checkbox is on and portrait dropdown is Off,
the crop bar appears and the video overlay shows 2 red vertical lines
(instead of filled red bands) indicating the 9:16 crop boundaries.
Clicking the crop bar or video adjusts the crop center position.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

main.py

@@ -717,6 +717,7 @@ class MpvWidget(QWidget):
         self._do_file_loaded.connect(self._on_file_loaded_qt)
         self._overlay_ratio: tuple[int, int] | None = None  # (num, den) or None
         self._overlay_crop_center: float = 0.5
+        self._overlay_lines_only: bool = False
         self._overlay_fracs: "tuple[float, float] | None" = None  # (left_frac, right_frac)
 
         @self._player.event_callback("file-loaded")
@@ -729,9 +730,11 @@ class MpvWidget(QWidget):
         self._overlay_fracs = None  # recompute with new dimensions
         self.file_loaded.emit()
 
-    def set_crop_overlay(self, ratio: "tuple[int,int] | None", crop_center: float) -> None:
+    def set_crop_overlay(self, ratio: "tuple[int,int] | None", crop_center: float,
+                         lines_only: bool = False) -> None:
         self._overlay_ratio = ratio
         self._overlay_crop_center = crop_center
+        self._overlay_lines_only = lines_only
         self._overlay_fracs: "tuple[float,float] | None" = None  # invalidate cache
         self.update()
 
@@ -789,6 +792,13 @@ class MpvWidget(QWidget):
                 ww, wh = self.width(), self.height()
                 left_px  = int(left_frac  * ww)
                 right_px = int(right_frac * ww)
+                if self._overlay_lines_only:
+                    line_pen = QPen(QColor(220, 60, 60, 200))
+                    line_pen.setWidth(2)
+                    p.setPen(line_pen)
+                    p.drawLine(left_px, 0, left_px, wh)
+                    p.drawLine(right_px, 0, right_px, wh)
+                else:
                     cut_color = QColor(180, 0, 0, 140)
                     if left_px > 0:
                         p.fillRect(0, 0, left_px, wh, cut_color)
@@ -1322,6 +1332,7 @@ class MainWindow(QMainWindow):
         self._chk_rand_portrait.toggled.connect(
             lambda v: self._settings.setValue("rand_portrait", "true" if v else "false")
         )
+        self._chk_rand_portrait.toggled.connect(self._on_rand_portrait_toggled)
 
         self._txt_label = QComboBox()
         self._txt_label.setEditable(True)
@@ -1463,9 +1474,16 @@ class MainWindow(QMainWindow):
 
         self.setCentralWidget(splitter)
         self.setStatusBar(QStatusBar())
-        self._crop_bar.setVisible(saved_ratio != "Off")
+        _rand_portrait_on = self._settings.value("rand_portrait", "false") == "true"
         if saved_ratio != "Off":
+            self._crop_bar.setVisible(True)
             self._mpv.set_crop_overlay(_RATIOS[saved_ratio], self._crop_center)
+        elif _rand_portrait_on:
+            self._crop_bar.set_portrait_ratio("9:16")
+            self._crop_bar.setVisible(True)
+            self._mpv.set_crop_overlay(_RATIOS["9:16"], self._crop_center, lines_only=True)
+        else:
+            self._crop_bar.setVisible(False)
 
         # Application-wide shortcuts — fire regardless of which widget has focus.
         ctx = Qt.ShortcutContext.ApplicationShortcut
@@ -1590,20 +1608,44 @@ class MainWindow(QMainWindow):
     def _on_portrait_ratio_changed(self, text: str) -> None:
         ratio = None if text == "Off" else text
         self._crop_bar.set_portrait_ratio(ratio)
-        self._crop_bar.setVisible(ratio is not None)
+        rand_on = self._chk_rand_portrait.isChecked()
+        # Show crop bar if portrait is set OR random portrait is on
+        if ratio is not None:
+            self._crop_bar.setVisible(True)
+            self._mpv.set_crop_overlay(_RATIOS[ratio], self._crop_center)
+        elif rand_on:
+            self._crop_bar.set_portrait_ratio("9:16")
+            self._crop_bar.setVisible(True)
+            self._mpv.set_crop_overlay(_RATIOS["9:16"], self._crop_center, lines_only=True)
+        else:
+            self._crop_bar.setVisible(False)
+            self._mpv.set_crop_overlay(None, self._crop_center)
         self._settings.setValue("portrait_ratio", text)
-        self._mpv.set_crop_overlay(
+
-            _RATIOS[ratio] if ratio else None, self._crop_center
+    def _on_rand_portrait_toggled(self, checked: bool) -> None:
-        )
+        ratio_text = self._cmb_portrait.currentText()
+        if ratio_text != "Off":
+            return  # manual portrait already controls the overlay
+        if checked:
+            self._crop_bar.set_portrait_ratio("9:16")
+            self._crop_bar.setVisible(True)
+            self._mpv.set_crop_overlay(_RATIOS["9:16"], self._crop_center, lines_only=True)
+        else:
+            self._crop_bar.setVisible(False)
+            self._mpv.set_crop_overlay(None, self._crop_center)
 
     def _on_crop_click(self, frac: float) -> None:
         ratio = self._cmb_portrait.currentText()
-        if ratio == "Off":
+        rand_on = self._chk_rand_portrait.isChecked()
+        if ratio == "Off" and not rand_on:
             return
         self._crop_center = max(0.0, min(1.0, frac))
         self._settings.setValue("crop_center", str(self._crop_center))
         self._crop_bar.set_crop_center(self._crop_center)
+        if ratio != "Off":
             self._mpv.set_crop_overlay(_RATIOS[ratio], self._crop_center)
+        else:
+            self._mpv.set_crop_overlay(_RATIOS["9:16"], self._crop_center, lines_only=True)
 
     # --- End-frame preview ---