fix: improve macOS UX (HiDPI support and native key labels)

mask_canvas.py

@@ -246,6 +246,7 @@ def paintEvent(self, event):
             Qt.KeepAspectRatio,
             Qt.SmoothTransformation
         )
+        scaled_pixmap.setDevicePixelRatio(self.screen().devicePixelRatio() if self.screen() else 1.0)
         painter.drawPixmap(0, 0, scaled_pixmap)
 
         # マスクオーバーレイを描画
@@ -298,6 +299,8 @@ def _create_mask_overlay(self) -> QPixmap:
             Qt.SmoothTransformation
         )
 
+        scaled_pixmap.setDevicePixelRatio(self.screen().devicePixelRatio() if self.screen() else 1.0)
+
         return scaled_pixmap
 
     def mousePressEvent(self, event):

mask_composer.py

@@ -337,12 +337,12 @@ def _setup_ui(self):
         # Undo/Redoボタン
         undo_redo_layout = QHBoxLayout()
         self.btn_undo = QPushButton('戻す')
-        self.btn_undo.setToolTip('Ctrl+Z')
+        self.btn_undo.setToolTip(QKeySequence(QKeySequence.StandardKey.Undo).toString(QKeySequence.SequenceFormat.NativeText))
         self.btn_undo.clicked.connect(self._on_undo)
         undo_redo_layout.addWidget(self.btn_undo)
 
         self.btn_redo = QPushButton('やり直し')
-        self.btn_redo.setToolTip('Ctrl+Y')
+        self.btn_redo.setToolTip(QKeySequence(QKeySequence.StandardKey.Redo).toString(QKeySequence.SequenceFormat.NativeText))
         self.btn_redo.clicked.connect(self._on_redo)
         undo_redo_layout.addWidget(self.btn_redo)
         brush_layout.addLayout(undo_redo_layout)

parts_mixer.py

@@ -340,12 +340,12 @@ def _setup_ui(self):
         # Undo/Redo
         undo_layout = QHBoxLayout()
         self.btn_undo = QPushButton('戻す')
-        self.btn_undo.setToolTip('Ctrl+Z')
+        self.btn_undo.setToolTip(QKeySequence(QKeySequence.StandardKey.Undo).toString(QKeySequence.SequenceFormat.NativeText))
         self.btn_undo.clicked.connect(self._on_undo)
         undo_layout.addWidget(self.btn_undo)
 
         self.btn_redo = QPushButton('やり直し')
-        self.btn_redo.setToolTip('Ctrl+Y')
+        self.btn_redo.setToolTip(QKeySequence(QKeySequence.StandardKey.Redo).toString(QKeySequence.SequenceFormat.NativeText))
         self.btn_redo.clicked.connect(self._on_redo)
         undo_layout.addWidget(self.btn_redo)
         brush_layout.addLayout(undo_layout)

preview_widget.py

@@ -184,16 +184,20 @@ def update_display(self):
             return
 
         # スケール適用
-        if self.scale != 1.0:
+        # Apply scale and device pixel ratio for HiDPI displays
+        dpr = self._device_pixel_ratio()
+        effective_scale = self.scale * dpr
+        if effective_scale != 1.0:
             h, w = display.shape[:2]
-            new_w = int(w * self.scale)
-            new_h = int(h * self.scale)
+            new_w = max(1, int(w * effective_scale))
+            new_h = max(1, int(h * effective_scale))
             display = cv2.resize(display, (new_w, new_h), interpolation=cv2.INTER_NEAREST)
 
         # QImageに変換
         try:
             qimage = convert_to_qimage(display)
             pixmap = QPixmap.fromImage(qimage)
+            pixmap.setDevicePixelRatio(dpr)
             self.label.setPixmap(pixmap)
         except Exception as e:
             print(f"Display error: {e}")
@@ -381,6 +385,13 @@ def mouseReleaseEvent(self, event: QMouseEvent):
             # ブラシモード
             self.mouse_released.emit(img_x, img_y)
 
+    def _device_pixel_ratio(self) -> float:
+        """Get the device pixel ratio for HiDPI support."""
+        screen = self.screen()
+        if screen is not None:
+            return screen.devicePixelRatio()
+        return 1.0
+
     def wheelEvent(self, event):
         """ホイールイベント（ズーム）"""
         delta = event.angleDelta().y()