完善

lib/utils/book/book_dao.dart

@@ -82,6 +82,12 @@ class BookDao {
     );
   });
 
+  // 仅更新封面偏移量（不触发全量刷新）
+  Future<void> updateCoverOffset(String bookId, double offset) => _wrap('updateCoverOffset', () async {
+    final db = await _dbHelper.database;
+    await db.update('books', {'cover_offset': offset}, where: 'id = ?', whereArgs: [bookId]);
+  });
+
   // 软删除书籍记录（移入回收站）
   Future<int> deleteBook(String id) => _wrap('deleteBook', () async {
     final db = await _dbHelper.database;

lib/utils/database_helper.dart

@@ -57,7 +57,7 @@ class DatabaseHelper {
 
     return await openDatabase(
       path,
-      version: 15,
+      version: 16,
       onCreate: _createDB,
       onUpgrade: _onUpgrade,
     );
@@ -119,8 +119,26 @@ class DatabaseHelper {
       await _createReaderBooksTable(db);
     }
     if (oldVersion < 15) {
-      await db.execute('ALTER TABLE movies ADD COLUMN cover_offset REAL DEFAULT 0');
-      await db.execute('ALTER TABLE books ADD COLUMN cover_offset REAL DEFAULT 0');
+      // 安全添加 cover_offset 列（防止列已存在时报错）
+      final movieCols = await db.rawQuery('PRAGMA table_info(movies)');
+      if (!movieCols.any((col) => col['name'] == 'cover_offset')) {
+        await db.execute('ALTER TABLE movies ADD COLUMN cover_offset REAL DEFAULT 0');
+      }
+      final bookCols = await db.rawQuery('PRAGMA table_info(books)');
+      if (!bookCols.any((col) => col['name'] == 'cover_offset')) {
+        await db.execute('ALTER TABLE books ADD COLUMN cover_offset REAL DEFAULT 0');
+      }
+    }
+    // v16: 确保 cover_offset 列存在（v15 的数据库可能缺少此列）
+    if (oldVersion < 16) {
+      final movieCols = await db.rawQuery('PRAGMA table_info(movies)');
+      if (!movieCols.any((col) => col['name'] == 'cover_offset')) {
+        await db.execute('ALTER TABLE movies ADD COLUMN cover_offset REAL DEFAULT 0');
+      }
+      final bookCols = await db.rawQuery('PRAGMA table_info(books)');
+      if (!bookCols.any((col) => col['name'] == 'cover_offset')) {
+        await db.execute('ALTER TABLE books ADD COLUMN cover_offset REAL DEFAULT 0');
+      }
     }
   }
 

lib/utils/movie/movie_dao.dart

@@ -139,6 +139,12 @@ class MovieDao {
     );
   });
 
+  // 仅更新封面偏移量（不触发全量刷新）
+  Future<void> updateCoverOffset(String movieId, double offset) => _wrap('updateCoverOffset', () async {
+    final db = await _dbHelper.database;
+    await db.update('movies', {'cover_offset': offset}, where: 'id = ?', whereArgs: [movieId]);
+  });
+
   // 删除影视记录（软删除）
   Future<int> deleteMovie(String id) => _wrap('deleteMovie', () async {
     final db = await _dbHelper.database;

lib/utils/user_prefs.dart

@@ -61,6 +61,12 @@ class UserPrefs {
   int get detailPageStyle => prefs.getInt('detailPageStyle') ?? 0;
   Future<bool> setDetailPageStyle(int value) => prefs.setInt('detailPageStyle', value);
 
+  // ========== 封面位置 ==========
+
+  /// 获取封面偏移量（-1.0 到 1.0，0 = 居中）
+  double getCoverOffset(String itemId) => prefs.getDouble('coverOffset_$itemId') ?? 0.0;
+  Future<bool> setCoverOffset(String itemId, double value) => prefs.setDouble('coverOffset_$itemId', value);
+
   // ========== 主界面显示设置 ==========
 
   /// 是否启用底部导航栏滚动隐藏（默认开启）