T-573 修复封面画廊候选图宽度

app/gui/tabs/generate.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from PySide6.QtCore import QEvent
+from PySide6.QtCore import QEvent, QSize
 
 from ..models import GenerateTaskTableModel
 from ..widgets import *
@@ -188,13 +188,14 @@ class CoverGalleryDialog(QDialog):
         self.status_label.setWordWrap(True)
         layout.addWidget(self.status_label)
 
-        scroll = QScrollArea()
-        scroll.setObjectName("coverGalleryScrollArea")
-        scroll.setWidgetResizable(False)
-        scroll.setHorizontalScrollBarPolicy(Qt.ScrollBarAsNeeded)
-        scroll.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
-        content = QWidget()
-        self.candidate_layout = QHBoxLayout(content)
+        self.candidate_scroll = QScrollArea()
+        self.candidate_scroll.setObjectName("coverGalleryScrollArea")
+        self.candidate_scroll.setWidgetResizable(False)
+        self.candidate_scroll.setHorizontalScrollBarPolicy(Qt.ScrollBarAsNeeded)
+        self.candidate_scroll.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
+        self.candidate_content = QWidget()
+        self.candidate_content.setObjectName("coverGalleryCandidateContent")
+        self.candidate_layout = QHBoxLayout(self.candidate_content)
         self.candidate_layout.setContentsMargins(0, 0, 0, 0)
         self.candidate_layout.setSpacing(12)
         if self.candidates:
@@ -207,8 +208,9 @@ class CoverGalleryDialog(QDialog):
             empty_label.setMinimumSize(320, self.THUMBNAIL_SIZE)
             empty_label.setAlignment(Qt.AlignCenter)
             self.candidate_layout.addWidget(empty_label)
-        scroll.setWidget(content)
-        layout.addWidget(scroll, 1)
+        self._sync_candidate_content_size()
+        self.candidate_scroll.setWidget(self.candidate_content)
+        layout.addWidget(self.candidate_scroll, 1)
         return panel
 
     def _candidate_item(self, candidate_path, index):
@@ -252,6 +254,38 @@ class CoverGalleryDialog(QDialog):
         layout.addStretch(1)
         return item
 
+    def _sync_candidate_content_size(self):
+        layout = getattr(self, "candidate_layout", None)
+        content = getattr(self, "candidate_content", None)
+        if layout is None or content is None:
+            return
+        layout.activate()
+        margins = layout.contentsMargins()
+        spacing = max(0, layout.spacing())
+        hint = layout.sizeHint()
+        if self.candidates:
+            candidate_count = len(self.candidates)
+            min_width = (
+                margins.left()
+                + margins.right()
+                + candidate_count * (self.THUMBNAIL_SIZE + 16)
+                + max(0, candidate_count - 1) * spacing
+            )
+        else:
+            min_width = margins.left() + margins.right() + 320
+        min_height = max(
+            self.THUMBNAIL_SIZE,
+            hint.height(),
+            content.minimumHeight(),
+        )
+        size = QSize(max(min_width, hint.width()), min_height)
+        content.setMinimumSize(size)
+        content.resize(size)
+        content.updateGeometry()
+        scroll = getattr(self, "candidate_scroll", None)
+        if scroll is not None:
+            scroll.updateGeometry()
+
     def _sync_initial_selection(self):
         for candidate_path, radio in self.candidate_buttons.items():
             if _same_file(candidate_path, self.current_path):
@@ -560,6 +594,7 @@ class CoverGalleryDialog(QDialog):
             empty_label.setMinimumSize(320, self.THUMBNAIL_SIZE)
             empty_label.setAlignment(Qt.AlignCenter)
             self.candidate_layout.addWidget(empty_label)
+        self._sync_candidate_content_size()
         self._install_navigation_event_filters()
 
     def _on_regenerate_progress(self, payload):

docs/tasks/T-573.md

@@ -3,7 +3,7 @@ id: T-573
 title: ②封面画廊候选图横向滚动内容宽度修复
 phase: 7
 deps: [T-567, T-569]
-status: TODO
+status: DONE
 created: 2026-07-09
 ---
 
@@ -65,4 +65,12 @@ T-568/T-569 后封面画廊支持切换任务和重新生成，候选图列表
 
 ## 执行记录
 
-（做完在这里写：改了什么文件、跑了什么验证命令及结果、关键决策。）
+- 2026-07-09：已完成。
+  - `app/gui/tabs/generate.py`：`CoverGalleryDialog` 保存 `candidate_scroll` / `candidate_content` 引用，新增 `_sync_candidate_content_size()`；候选图初始化和 `_rebuild_candidate_items()` 后按候选数量、item 宽度、spacing 与 layout sizeHint 同步 content 最小尺寸和实际尺寸，保留横向滚动行为。
+  - `tests/test_gui.py`：新增多候选图内容宽度测试，以及从少候选任务切换到多候选任务后的宽度重新同步测试。
+  - 验证通过：
+    - `py -3.10 -m unittest tests.test_gui`
+    - `python -m ruff check app tests main.py`
+    - `py -3.10 -m compileall app main.py`
+    - `py -3.10 -m unittest discover -s tests`
+    - `git diff --check`

tests/test_gui.py

@@ -2277,6 +2277,60 @@ class GuiTests(TempDirMixin, unittest.TestCase):
 
         self.assert_removed(temp_dir)
 
+    def test_cover_gallery_candidate_content_width_fits_multiple_candidates(self):
+        with self.make_temp_dir() as temp_dir:
+            cfg, account, tasks, canonicals, _archives = self._cover_gallery_task_set(temp_dir, count=1)
+            prefix = os.path.splitext(canonicals[0])[0]
+            self.write_test_image(f"{prefix}_20260709101100.jpg")
+            self.write_test_image(f"{prefix}_20260709101200.jpg")
+
+            dialog = CoverGalleryDialog(tasks[0], cfg["image_dir"], cfg["db_path"], account=account)
+            self.addCleanup(dialog.close)
+
+            self.assertGreaterEqual(len(dialog.candidates), 4)
+            expected_width = (
+                len(dialog.candidates) * (dialog.THUMBNAIL_SIZE + 16)
+                + (len(dialog.candidates) - 1) * dialog.candidate_layout.spacing()
+            )
+            self.assertIs(dialog.candidate_scroll.widget(), dialog.candidate_content)
+            self.assertGreaterEqual(dialog.candidate_content.minimumWidth(), expected_width)
+            self.assertGreaterEqual(dialog.candidate_content.width(), expected_width)
+
+        self.assert_removed(temp_dir)
+
+    def test_cover_gallery_switch_task_resyncs_candidate_content_width(self):
+        with self.make_temp_dir() as temp_dir:
+            cfg, account, tasks, canonicals, archives = self._cover_gallery_task_set(temp_dir, count=2)
+            os.remove(archives[0])
+            prefix = os.path.splitext(canonicals[1])[0]
+            self.write_test_image(f"{prefix}_20260709101100.jpg")
+            self.write_test_image(f"{prefix}_20260709101200.jpg")
+            dialog = CoverGalleryDialog(
+                tasks[0],
+                cfg["image_dir"],
+                cfg["db_path"],
+                account=account,
+                visible_tasks=tasks,
+                task_index=0,
+                account_by_alias={"alias-a": account},
+            )
+            self.addCleanup(dialog.close)
+            initial_width = dialog.candidate_content.minimumWidth()
+
+            self.assertTrue(dialog.switch_task(1))
+
+            expected_width = (
+                len(dialog.candidates) * (dialog.THUMBNAIL_SIZE + 16)
+                + (len(dialog.candidates) - 1) * dialog.candidate_layout.spacing()
+            )
+            self.assertEqual(tasks[1].id, dialog.task.id)
+            self.assertGreater(len(dialog.candidates), 2)
+            self.assertGreater(dialog.candidate_content.minimumWidth(), initial_width)
+            self.assertGreaterEqual(dialog.candidate_content.minimumWidth(), expected_width)
+            self.assertGreaterEqual(dialog.candidate_content.width(), expected_width)
+
+        self.assert_removed(temp_dir)
+
     def test_cover_gallery_save_switches_current_cover(self):
         with self.make_temp_dir() as temp_dir:
             cfg = self.make_config(temp_dir)