fix(gui): make cover gallery previews responsive

app/gui/tabs/generate.py

@@ -34,31 +34,88 @@ class OriginalImageDialog(QDialog):
     def __init__(self, image_path, parent=None):
         super().__init__(parent)
         self.image_path = image_path
+        self.image = QImage(str(image_path))
+        self.fit_to_window = True
+        self._display_size = QSize()
+        self._resize_timer = QTimer(self)
+        self._resize_timer.setSingleShot(True)
+        self._resize_timer.setInterval(50)
+        self._resize_timer.timeout.connect(self._update_image_display)
         self.setWindowTitle(os.path.basename(str(image_path or "")) or "原图")
         layout = QVBoxLayout(self)
-        image = QImage(str(image_path))
+        self.scroll = QScrollArea()
-        scroll = QScrollArea()
+        self.scroll.setObjectName("originalImageScrollArea")
-        scroll.setWidgetResizable(False)
+        self.scroll.setWidgetResizable(False)
-        image_label = QLabel()
+        self.image_label = QLabel()
-        image_label.setAlignment(Qt.AlignCenter)
+        self.image_label.setObjectName("originalImageLabel")
-        if image.isNull():
+        self.image_label.setAlignment(Qt.AlignCenter)
-            image_label.setText("图片读取失败")
+        if self.image.isNull():
+            self.image_label.setText("图片读取失败")
         else:
             self.setWindowTitle(
-                f"{os.path.basename(str(image_path))} · {image.width()}x{image.height()}"
+                f"{os.path.basename(str(image_path))} · {self.image.width()}x{self.image.height()}"
             )
-            pixmap = QPixmap.fromImage(image)
+        self.scroll.setWidget(self.image_label)
-            image_label.setPixmap(pixmap)
+        layout.addWidget(self.scroll, 1)
-            image_label.resize(pixmap.size())
-        scroll.setWidget(image_label)
-        layout.addWidget(scroll, 1)
         button_layout = QHBoxLayout()
         button_layout.addStretch(1)
+        self.display_mode_button = QPushButton("原始尺寸")
+        self.display_mode_button.setObjectName("originalImageDisplayModeButton")
+        self.display_mode_button.setToolTip("按图片原始像素查看")
+        self.display_mode_button.setEnabled(not self.image.isNull())
+        self.display_mode_button.clicked.connect(self.toggle_display_mode)
+        button_layout.addWidget(self.display_mode_button)
         close_button = QPushButton("关闭")
         close_button.clicked.connect(self.reject)
         button_layout.addWidget(close_button)
         layout.addLayout(button_layout)
-        self._fit_to_screen(image)
+        self._fit_to_screen(self.image)
+        self._update_image_display()
+        QTimer.singleShot(0, self._update_image_display)
+
+    def resizeEvent(self, event):
+        super().resizeEvent(event)
+        self._resize_timer.start()
+
+    def toggle_display_mode(self, checked=False):
+        self.fit_to_window = not self.fit_to_window
+        if self.fit_to_window:
+            self.display_mode_button.setText("原始尺寸")
+            self.display_mode_button.setToolTip("按图片原始像素查看")
+        else:
+            self.display_mode_button.setText("适应窗口")
+            self.display_mode_button.setToolTip("缩放图片以完整显示在窗口内")
+        self._display_size = QSize()
+        self._update_image_display()
+        QTimer.singleShot(0, self._update_image_display)
+
+    def _update_image_display(self):
+        viewport_size = self.scroll.viewport().size()
+        viewport_width = max(1, viewport_size.width())
+        viewport_height = max(1, viewport_size.height())
+        if self.image.isNull():
+            self.image_label.clear()
+            self.image_label.setText("图片读取失败")
+            self.image_label.resize(viewport_width, viewport_height)
+            return
+        if self.fit_to_window:
+            target_size = QSize(viewport_width, viewport_height)
+            pixmap = QPixmap.fromImage(
+                self.image.scaled(
+                    target_size,
+                    Qt.KeepAspectRatio,
+                    Qt.SmoothTransformation,
+                )
+            )
+            label_size = target_size
+        else:
+            pixmap = QPixmap.fromImage(self.image)
+            label_size = pixmap.size()
+        if self._display_size == label_size and self.image_label.pixmap() is not None:
+            return
+        self.image_label.setPixmap(pixmap)
+        self.image_label.resize(label_size)
+        self._display_size = QSize(label_size)
 
     def _fit_to_screen(self, image):
         available = _available_geometry()
@@ -132,6 +189,8 @@ class _SegmentedProgressBar(QProgressBar):
 
 class CoverGalleryDialog(QDialog):
     THUMBNAIL_SIZE = 180
+    MAX_THUMBNAIL_SIZE = 360
+    CANDIDATE_TEXT_HEIGHT = 72
     OLD_THUMBNAIL_SIZE = 300
 
     def __init__(
@@ -163,6 +222,14 @@ class CoverGalleryDialog(QDialog):
         self.current_path = _normalize_file_path(getattr(task, "new_cover_path", None))
         self.selected_path = None
         self.changed = False
+        self.candidate_thumbnail_size = self.THUMBNAIL_SIZE
+        self.candidate_images = {}
+        self.candidate_thumbnails = {}
+        self.candidate_items = {}
+        self._candidate_resize_timer = QTimer(self)
+        self._candidate_resize_timer.setSingleShot(True)
+        self._candidate_resize_timer.setInterval(60)
+        self._candidate_resize_timer.timeout.connect(self._update_candidate_thumbnail_layout)
         self.candidate_buttons = {}
         self.button_group = QButtonGroup(self)
         self.button_group.setExclusive(True)
@@ -203,6 +270,7 @@ class CoverGalleryDialog(QDialog):
         self._update_reset_cover_button_state()
         self._fit_to_screen()
         self._install_navigation_event_filters()
+        QTimer.singleShot(0, self._update_candidate_thumbnail_layout)
 
     def _old_cover_panel(self):
         panel = QWidget()
@@ -267,28 +335,30 @@ class CoverGalleryDialog(QDialog):
 
     def _candidate_item(self, candidate_path, index):
         item = QWidget()
-        item.setFixedWidth(self.THUMBNAIL_SIZE + 16)
+        item.setFixedWidth(self.candidate_thumbnail_size + 16)
         layout = QVBoxLayout(item)
         layout.setContentsMargins(0, 0, 0, 0)
         thumbnail = _CoverThumbnailLabel(candidate_path, self.open_original_image)
         thumbnail.setObjectName("coverCandidateThumbnail")
         thumbnail.setAlignment(Qt.AlignCenter)
         image = _load_image(candidate_path)
+        self.candidate_images[candidate_path] = image
+        self.candidate_thumbnails[candidate_path] = thumbnail
+        self.candidate_items[candidate_path] = item
         if image.isNull():
             thumbnail.setText("图片读取失败")
-            thumbnail.setMinimumSize(self.THUMBNAIL_SIZE, self.THUMBNAIL_SIZE)
         else:
             thumbnail.setPixmap(
                 QPixmap.fromImage(
                     image.scaled(
-                        self.THUMBNAIL_SIZE,
+                        self.candidate_thumbnail_size,
-                        self.THUMBNAIL_SIZE,
+                        self.candidate_thumbnail_size,
                         Qt.KeepAspectRatio,
                         Qt.SmoothTransformation,
                     )
                 )
             )
-            thumbnail.setMinimumSize(self.THUMBNAIL_SIZE, self.THUMBNAIL_SIZE)
+        thumbnail.setFixedSize(self.candidate_thumbnail_size, self.candidate_thumbnail_size)
         radio = QRadioButton(_candidate_label(candidate_path, self.current_path))
         radio.setObjectName(f"coverCandidateRadio{index}")
         radio.setFocusPolicy(Qt.ClickFocus)
@@ -320,15 +390,14 @@ class CoverGalleryDialog(QDialog):
             min_width = (
                 margins.left()
                 + margins.right()
-                + candidate_count * (self.THUMBNAIL_SIZE + 16)
+                + candidate_count * (self.candidate_thumbnail_size + 16)
                 + max(0, candidate_count - 1) * spacing
             )
         else:
             min_width = margins.left() + margins.right() + 320
         min_height = max(
-            self.THUMBNAIL_SIZE,
+            self.candidate_thumbnail_size,
             hint.height(),
-            content.minimumHeight(),
         )
         size = QSize(max(min_width, hint.width()), min_height)
         content.setMinimumSize(size)
@@ -338,6 +407,64 @@ class CoverGalleryDialog(QDialog):
         if scroll is not None:
             scroll.updateGeometry()
 
+    def resizeEvent(self, event):
+        super().resizeEvent(event)
+        self._candidate_resize_timer.start()
+
+    def _candidate_thumbnail_target_size(self):
+        scroll = getattr(self, "candidate_scroll", None)
+        if scroll is None or not self.candidates:
+            return self.THUMBNAIL_SIZE
+        viewport = scroll.viewport()
+        viewport_width = viewport.width()
+        viewport_height = viewport.height()
+        if viewport_width <= 0 or viewport_height <= 0:
+            return self.candidate_thumbnail_size
+        visible_count = min(3, max(1, len(self.candidates)))
+        spacing = max(0, self.candidate_layout.spacing())
+        width_budget = (
+            viewport_width
+            - max(0, visible_count - 1) * spacing
+            - visible_count * 16
+        ) // visible_count
+        height_budget = viewport_height - self.CANDIDATE_TEXT_HEIGHT
+        target = min(width_budget, height_budget, self.MAX_THUMBNAIL_SIZE)
+        return max(self.THUMBNAIL_SIZE, int(target))
+
+    def _update_candidate_thumbnail_layout(self):
+        if not self.candidates:
+            self._sync_candidate_content_size()
+            return
+        target_size = self._candidate_thumbnail_target_size()
+        if target_size == self.candidate_thumbnail_size:
+            self._sync_candidate_content_size()
+            return
+        self.candidate_thumbnail_size = target_size
+        for candidate_path in self.candidates:
+            item = self.candidate_items.get(candidate_path)
+            thumbnail = self.candidate_thumbnails.get(candidate_path)
+            image = self.candidate_images.get(candidate_path)
+            if item is not None:
+                item.setFixedWidth(target_size + 16)
+            if thumbnail is None:
+                continue
+            thumbnail.setFixedSize(target_size, target_size)
+            thumbnail.clear()
+            if image is None or image.isNull():
+                thumbnail.setText("图片读取失败")
+                continue
+            thumbnail.setPixmap(
+                QPixmap.fromImage(
+                    image.scaled(
+                        target_size,
+                        target_size,
+                        Qt.KeepAspectRatio,
+                        Qt.SmoothTransformation,
+                    )
+                )
+            )
+        self._sync_candidate_content_size()
+
     def _sync_initial_selection(self):
         for candidate_path, radio in self.candidate_buttons.items():
             if _same_file(candidate_path, self.current_path):
@@ -609,6 +736,9 @@ class CoverGalleryDialog(QDialog):
     def _rebuild_candidate_items(self):
         _clear_layout(self.candidate_layout)
         self.candidate_buttons = {}
+        self.candidate_images = {}
+        self.candidate_thumbnails = {}
+        self.candidate_items = {}
         self.button_group = QButtonGroup(self)
         self.button_group.setExclusive(True)
         if self.candidates:
@@ -622,6 +752,7 @@ class CoverGalleryDialog(QDialog):
             empty_label.setAlignment(Qt.AlignCenter)
             self.candidate_layout.addWidget(empty_label)
         self._sync_candidate_content_size()
+        self._candidate_resize_timer.start()
         self._install_navigation_event_filters()
 
     def _fit_to_screen(self):
@@ -631,7 +762,7 @@ class CoverGalleryDialog(QDialog):
             return
         max_width = max(520, int(available.width() * 0.9))
         max_height = max(420, int(available.height() * 0.9))
-        self.resize(min(960, max_width), min(580, max_height))
+        self.resize(min(1180, max_width), min(720, max_height))
         _center_dialog(self, available)
 
 

docs/tasks/T-626.md

@@ -3,7 +3,7 @@ id: T-626
 title: ②封面画廊生成图随窗口自适应显示
 phase: 7
 deps: [T-574]
-status: TODO
+status: DONE
 created: 2026-07-13
 ---
 
@@ -75,4 +75,10 @@ T-573 只修复了候选图横向容器没有按数量撑开导致的遮挡问
 
 ## 执行记录
 
-- 待实现。
+- 2026-07-14：完成 T-626。
+  - `app/gui/tabs/generate.py`：封面画廊候选图改为按候选区 viewport、候选数量和可用高度在 `180～360px` 内动态计算；候选 item、缩略图和横向内容宽度使用同一尺寸，窗口 resize、任务切换和候选重建后自动同步。
+  - 候选原始 `QImage` 在当前任务画廊内缓存，连续 resize 使用单次计时器合并重绘；预览继续使用 `Qt.KeepAspectRatio` 和平滑缩放，读取失败时保持中文占位。
+  - `OriginalImageDialog` 默认按窗口完整显示图片，新增「原始尺寸 / 适应窗口」切换；原始尺寸保留滚动查看，窗口尺寸变化后自动更新预览。
+  - `tests/test_gui.py`：新增候选图随窗口变化、非方图比例、损坏图片占位、任务切换后响应式尺寸，以及原图双模式和失败占位测试；既有候选内容宽度断言改为使用当前动态尺寸。
+  - 主工作区存在与本任务无关的默认封面模板未提交改名，导致两项旧模板断言失败；未回退用户改动，在基于 `HEAD` 的干净 worktree 中仅套用 T-626 代码和测试差异完成验证。
+  - 验证通过：`py -3.10 -m unittest tests.test_gui`（179 tests）、`py -3.10 -m unittest discover -s tests`（444 tests）、`python -m ruff check app tests main.py`、`py -3.10 -m compileall app main.py`、`git diff --check`。

tests/test_gui.py

@@ -4069,7 +4069,7 @@ class GuiTests(TempDirMixin, unittest.TestCase):
 
             self.assertGreaterEqual(len(dialog.candidates), 4)
             expected_width = (
-                len(dialog.candidates) * (dialog.THUMBNAIL_SIZE + 16)
+                len(dialog.candidates) * (dialog.candidate_thumbnail_size + 16)
                 + (len(dialog.candidates) - 1) * dialog.candidate_layout.spacing()
             )
             self.assertIs(dialog.candidate_scroll.widget(), dialog.candidate_content)
@@ -4078,6 +4078,63 @@ class GuiTests(TempDirMixin, unittest.TestCase):
 
         self.assert_removed(temp_dir)
 
+    def test_cover_gallery_candidate_images_resize_with_viewport_and_keep_ratio(self):
+        with self.make_temp_dir() as temp_dir:
+            cfg, account, task, canonical = self._cover_gallery_task(temp_dir)
+            self.write_test_image(canonical, width=240, height=120)
+            dialog = CoverGalleryDialog(task, cfg["image_dir"], cfg["db_path"], account=account)
+            self.addCleanup(dialog.close)
+            dialog.show()
+
+            dialog.resize(650, 460)
+            QApplication.processEvents()
+            dialog._candidate_resize_timer.stop()
+            dialog._update_candidate_thumbnail_layout()
+            small_size = dialog.candidate_thumbnail_size
+            thumbnail = dialog.candidate_thumbnails[canonical]
+            small_pixmap = thumbnail.pixmap()
+
+            self.assertEqual(QSize(small_size, small_size), thumbnail.size())
+            self.assertIsNotNone(small_pixmap)
+            self.assertAlmostEqual(2.0, small_pixmap.width() / small_pixmap.height(), places=1)
+
+            dialog.resize(1100, 700)
+            QApplication.processEvents()
+            dialog._candidate_resize_timer.stop()
+            dialog._update_candidate_thumbnail_layout()
+            large_size = dialog.candidate_thumbnail_size
+            large_pixmap = thumbnail.pixmap()
+
+            self.assertGreater(large_size, small_size)
+            self.assertLessEqual(large_size, dialog.MAX_THUMBNAIL_SIZE)
+            self.assertEqual(QSize(large_size, large_size), thumbnail.size())
+            self.assertAlmostEqual(2.0, large_pixmap.width() / large_pixmap.height(), places=1)
+            expected_width = len(dialog.candidates) * (large_size + 16)
+            expected_width += max(0, len(dialog.candidates) - 1) * dialog.candidate_layout.spacing()
+            self.assertGreaterEqual(dialog.candidate_content.minimumWidth(), expected_width)
+
+        self.assert_removed(temp_dir)
+
+    def test_cover_gallery_broken_candidate_keeps_failure_placeholder_after_resize(self):
+        with self.make_temp_dir() as temp_dir:
+            cfg, account, task, canonical = self._cover_gallery_task(temp_dir)
+            with open(canonical, "wb") as fh:
+                fh.write(b"not-an-image")
+            dialog = CoverGalleryDialog(task, cfg["image_dir"], cfg["db_path"], account=account)
+            self.addCleanup(dialog.close)
+            dialog.resize(1000, 680)
+            dialog._update_candidate_thumbnail_layout()
+
+            thumbnail = dialog.candidate_thumbnails[canonical]
+            self.assertTrue(dialog.candidate_images[canonical].isNull())
+            self.assertEqual("图片读取失败", thumbnail.text())
+            self.assertEqual(
+                QSize(dialog.candidate_thumbnail_size, dialog.candidate_thumbnail_size),
+                thumbnail.size(),
+            )
+
+        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)
@@ -4100,7 +4157,7 @@ class GuiTests(TempDirMixin, unittest.TestCase):
             self.assertTrue(dialog.switch_task(1))
 
             expected_width = (
-                len(dialog.candidates) * (dialog.THUMBNAIL_SIZE + 16)
+                len(dialog.candidates) * (dialog.candidate_thumbnail_size + 16)
                 + (len(dialog.candidates) - 1) * dialog.candidate_layout.spacing()
             )
             self.assertEqual(tasks[1].id, dialog.task.id)
@@ -4111,6 +4168,40 @@ class GuiTests(TempDirMixin, unittest.TestCase):
 
         self.assert_removed(temp_dir)
 
+    def test_cover_gallery_switch_task_keeps_responsive_thumbnail_size(self):
+        with self.make_temp_dir() as temp_dir:
+            cfg, account, tasks, _canonicals, _archives = self._cover_gallery_task_set(
+                temp_dir,
+                count=2,
+            )
+            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)
+            dialog.resize(1100, 700)
+            dialog.show()
+            QApplication.processEvents()
+            dialog._candidate_resize_timer.stop()
+            dialog._update_candidate_thumbnail_layout()
+            responsive_size = dialog.candidate_thumbnail_size
+
+            self.assertGreater(responsive_size, dialog.THUMBNAIL_SIZE)
+            self.assertTrue(dialog.switch_task(1))
+            dialog._candidate_resize_timer.stop()
+            dialog._update_candidate_thumbnail_layout()
+
+            self.assertEqual(responsive_size, dialog.candidate_thumbnail_size)
+            for thumbnail in dialog.candidate_thumbnails.values():
+                self.assertEqual(QSize(responsive_size, responsive_size), thumbnail.size())
+
+        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)
@@ -4265,6 +4356,59 @@ class GuiTests(TempDirMixin, unittest.TestCase):
 
         self.assert_removed(temp_dir)
 
+    def test_original_image_dialog_switches_between_fit_and_original_size(self):
+        with self.make_temp_dir() as temp_dir:
+            image_path = self.write_test_image(
+                os.path.join(temp_dir, "large-cover.jpg"),
+                width=1200,
+                height=800,
+            )
+            dialog = OriginalImageDialog(image_path)
+            self.addCleanup(dialog.close)
+            dialog.resize(600, 450)
+            dialog.show()
+            QApplication.processEvents()
+            dialog._resize_timer.stop()
+            dialog._update_image_display()
+
+            fit_pixmap = dialog.image_label.pixmap()
+            viewport_size = dialog.scroll.viewport().size()
+            self.assertTrue(dialog.fit_to_window)
+            self.assertEqual("原始尺寸", dialog.display_mode_button.text())
+            self.assertLessEqual(fit_pixmap.width(), viewport_size.width())
+            self.assertLessEqual(fit_pixmap.height(), viewport_size.height())
+            self.assertAlmostEqual(1.5, fit_pixmap.width() / fit_pixmap.height(), places=1)
+
+            dialog.toggle_display_mode()
+
+            original_pixmap = dialog.image_label.pixmap()
+            self.assertFalse(dialog.fit_to_window)
+            self.assertEqual("适应窗口", dialog.display_mode_button.text())
+            self.assertEqual(QSize(1200, 800), original_pixmap.size())
+            self.assertEqual(QSize(1200, 800), dialog.image_label.size())
+
+            dialog.toggle_display_mode()
+
+            self.assertTrue(dialog.fit_to_window)
+            self.assertEqual("原始尺寸", dialog.display_mode_button.text())
+            self.assertLessEqual(dialog.image_label.pixmap().width(), dialog.scroll.viewport().width())
+            self.assertLessEqual(dialog.image_label.pixmap().height(), dialog.scroll.viewport().height())
+
+        self.assert_removed(temp_dir)
+
+    def test_original_image_dialog_keeps_chinese_failure_placeholder(self):
+        with self.make_temp_dir() as temp_dir:
+            dialog = OriginalImageDialog(os.path.join(temp_dir, "missing.jpg"))
+            self.addCleanup(dialog.close)
+            dialog.resize(520, 400)
+            dialog._update_image_display()
+
+            self.assertTrue(dialog.image.isNull())
+            self.assertEqual("图片读取失败", dialog.image_label.text())
+            self.assertFalse(dialog.display_mode_button.isEnabled())
+
+        self.assert_removed(temp_dir)
+
     def test_cover_gallery_previous_next_switch_visible_tasks_without_resizing(self):
         with self.make_temp_dir() as temp_dir:
             cfg, account, tasks, canonicals, _archives = self._cover_gallery_task_set(temp_dir, count=3)