Allow auto scrolling through the list of books by pressing the X key. The speed of scrolling can be controlled in Preferences->Look & feel->Cover browser. Useful to have a "slideshow" of book covers

Fixes #1917634 [[Enhancement] Add slideshow capability to cover browser](https://bugs.launchpad.net/calibre/+bug/1917634)

manual/gui.rst

@@ -782,3 +782,5 @@ calibre has several keyboard shortcuts to save you time and mouse movement. Thes
       - Re-apply the current sort
     * - :kbd:`Ctrl+Q`
       - Quit calibre
+    * - :kbd:`X`
+      - Toggle autoscroll of the book list

src/calibre/customize/builtins.py

@@ -970,6 +970,12 @@ class ActionOpenFolder(InterfaceActionBase):
             ' calibre library')
 
 
+class ActionAutoscrollBooks(InterfaceActionBase):
+    name = 'Autoscroll Books'
+    actual_plugin = 'calibre.gui2.actions.auto_scroll:AutoscrollBooksAction'
+    description = _('Auto scroll through the list of books')
+
+
 class ActionSendToDevice(InterfaceActionBase):
     name = 'Send To Device'
     actual_plugin = 'calibre.gui2.actions.device:SendToDeviceAction'
@@ -1115,7 +1121,7 @@ plugins += [ActionAdd, ActionFetchAnnotations, ActionGenerateCatalog,
         ActionCopyToLibrary, ActionTweakEpub, ActionUnpackBook, ActionNextMatch, ActionStore,
         ActionPluginUpdater, ActionPickRandom, ActionEditToC, ActionSortBy,
         ActionMarkBooks, ActionEmbed, ActionTemplateTester, ActionTagMapper, ActionAuthorMapper,
-        ActionVirtualLibrary, ActionBrowseAnnotations, ActionTemplateFunctions]
+        ActionVirtualLibrary, ActionBrowseAnnotations, ActionTemplateFunctions, ActionAutoscrollBooks]
 
 # }}}
 

src/calibre/db/cache.py

@@ -2219,7 +2219,7 @@ class Cache(object):
                     for book in self._search(expr, virtual_fields=virtual_fields):
                         c[book].append(lib)
                 except Exception as e:
-                    c[book].append(_('[Error in virtual library {0}: {1}]').format(lib, str(e)))
+                    c[book].append(_('[Error in Virtual library {0}: {1}]').format(lib, str(e)))
             self.vls_for_books_cache = {b:tuple(sorted(libs, key=sort_key)) for b, libs in c.items()}
         if not book_ids:
             book_ids = self._all_book_ids()

src/calibre/gui2/__init__.py

@@ -124,7 +124,8 @@ def create_defs():
             'Edit Metadata', 'Send To Device', 'Save To Disk',
             'Connect Share', 'Copy To Library', None,
             'Convert Books', 'View', 'Open Folder', 'Show Book Details',
-            'Similar Books', 'Tweak ePub', None, 'Remove Books',
+            'Similar Books', 'Tweak ePub', None, 'Remove Books', None,
+            'Autoscroll Books'
             )
 
     defs['show_splash_screen'] = True
@@ -198,6 +199,7 @@ def create_defs():
     defs['browse_annots_restrict_to_type'] = None
     defs['browse_annots_use_stemmer'] = True
     defs['annots_export_format'] = 'txt'
+    defs['books_autoscroll_time'] = 2.0
 
 
 create_defs()

src/calibre/gui2/actions/auto_scroll.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python
+# vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
+# License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
+
+
+from calibre.gui2.actions import InterfaceAction
+
+
+class AutoscrollBooksAction(InterfaceAction):
+
+    name = 'Autoscroll Books'
+    action_spec = (_('Auto scroll through the book list'), 'auto-scroll.png',
+                   _('Auto scroll through the book list, particularly useful with the cover browser open'), _('X'))
+    dont_add_to = frozenset(('context-menu-device', 'menubar-device'))
+    action_type = 'current'
+
+    def genesis(self):
+        self.qaction.triggered.connect(self.gui.toggle_auto_scroll)
+
+    def location_selected(self, loc):
+        enabled = loc == 'library'
+        self.qaction.setEnabled(enabled)
+        self.menuless_qaction.setEnabled(enabled)

src/calibre/gui2/cover_flow.py

@@ -9,15 +9,19 @@ __docformat__ = 'restructuredtext en'
 Module to implement the Cover Flow feature
 '''
 
-import sys, os, time
+import os
+import sys
+import time
+from qt.core import (
+    QAction, QApplication, QDialog, QFont, QImage, QItemSelectionModel,
+    QKeySequence, QLabel, QSize, QSizePolicy, QStackedLayout, Qt, QTimer, pyqtSignal
+)
 
-from qt.core import (QImage, QSizePolicy, QTimer, QDialog, Qt, QSize, QAction,
-        QStackedLayout, QLabel, pyqtSignal, QKeySequence, QFont, QApplication, QItemSelectionModel)
-
-from calibre.ebooks.metadata import rating_to_stars
 from calibre.constants import islinux
-from calibre.gui2 import (config, available_height, available_width, gprefs,
+from calibre.ebooks.metadata import rating_to_stars
-        rating_font)
+from calibre.gui2 import (
+    available_height, available_width, config, gprefs, rating_font
+)
 from calibre_extensions import pictureflow
 
 
@@ -190,6 +194,12 @@ class CoverFlow(pictureflow.PictureFlow):
         if not gprefs['cover_browser_reflections']:
             self.setShowReflections(False)
 
+    def one_auto_scroll(self):
+        if self.currentSlide() >= self.count() - 1:
+            self.setCurrentSlide(0)
+        else:
+            self.showNext()
+
     def set_subtitle_font(self, for_ratings=True):
         if for_ratings:
             self.setSubtitleFont(QFont(rating_font()))
@@ -295,6 +305,28 @@ class CoverFlowMixin(object):
     def __init__(self, *args, **kwargs):
         pass
 
+    def one_auto_scroll(self):
+        cb_visible = self.cover_flow is not None and self.cb_splitter.button.isChecked()
+        if cb_visible:
+            self.cover_flow.one_auto_scroll()
+        else:
+            self.library_view.show_next_book()
+
+    def toggle_auto_scroll(self):
+        if not hasattr(self, 'auto_scroll_timer'):
+            self.auto_scroll_timer = t = QTimer(self)
+            t.timeout.connect(self.one_auto_scroll)
+        if self.auto_scroll_timer.isActive():
+            self.auto_scroll_timer.stop()
+        else:
+            self.one_auto_scroll()
+            self.auto_scroll_timer.start(int(1000 * gprefs['books_autoscroll_time']))
+
+    def update_auto_scroll_timeout(self):
+        if hasattr(self, 'auto_scroll_timer') and self.auto_scroll_timer.isActive():
+            self.auto_scroll_timer.stop()
+            self.toggle_auto_scroll()
+
     def init_cover_flow_mixin(self):
         self.cover_flow = None
         self.cf_last_updated_at = None

src/calibre/gui2/library/views.py

@@ -1290,6 +1290,14 @@ class BooksView(QTableView):  # {{{
                 self.set_current_row(row, select=False)
                 break
 
+    def show_next_book(self):
+        ci = self.currentIndex()
+        if not ci.isValid():
+            self.set_current_row()
+            return
+        n = (ci.row() + 1) % self.model().rowCount(QModelIndex())
+        self.set_current_row(n)
+
     @property
     def next_id(self):
         '''

src/calibre/gui2/pictureflow/pictureflow.cpp

@@ -1518,6 +1518,7 @@ void PictureFlow::timerEvent(QTimerEvent* event)
 
 void PictureFlow::dataChanged() { d->dataChanged(); }
 void PictureFlow::emitcurrentChanged(int index) { emit currentChanged(index); }
+int PictureFlow::count() const { return d->slideCount(); }
 
 int FlowImages::count() { return 0; }
 QImage FlowImages::image(int index) { Q_UNUSED(index); return QImage(); }

src/calibre/gui2/pictureflow/pictureflow.h

@@ -111,6 +111,8 @@ public:
   */
   void setImages(FlowImages *images);
 
+  int count() const;
+
   /*!
     Returns the dimension of each slide (in pixels).
   */
@@ -221,4 +223,3 @@ private:
   qreal device_pixel_ratio() const;
   qreal last_device_pixel_ratio;
 };
-

src/calibre/gui2/pictureflow/pictureflow.sip

@@ -35,6 +35,7 @@ public :
   PictureFlow(QWidget *parent /TransferThis/ = 0, int queueLength = 3);
 
   void setImages(FlowImages *images);
+  int count();
   
   QSize slideSize() const;
 

src/calibre/gui2/preferences/look_feel.py

@@ -425,6 +425,7 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
         r('cover_grid_show_title', gprefs)
         r('tag_browser_show_counts', gprefs)
         r('tag_browser_item_padding', gprefs)
+        r('books_autoscroll_time', gprefs)
 
         r('qv_respects_vls', gprefs)
         r('qv_dclick_changes_column', gprefs)
@@ -806,6 +807,7 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
             getattr(gui, view + '_view').set_row_header_visibility()
         gui.library_view.refresh_row_sizing()
         gui.grid_view.refresh_settings()
+        gui.update_auto_scroll_timeout()
         qv = get_quickview_action_plugin()
         if qv:
             qv.refill_quickview()

src/calibre/gui2/preferences/look_feel.ui

@@ -1251,6 +1251,32 @@ them to all have the same width and height</string>
          </property>
         </widget>
        </item>
+       <item row="9" column="0">
+        <widget class="QLabel" name="label_26">
+         <property name="text">
+          <string>Show ne&amp;xt cover during auto scroll after:</string>
+         </property>
+         <property name="buddy">
+          <cstring>opt_books_autoscroll_time</cstring>
+         </property>
+        </widget>
+       </item>
+       <item row="9" column="1">
+        <widget class="QDoubleSpinBox" name="opt_books_autoscroll_time">
+         <property name="suffix">
+          <string> seconds</string>
+         </property>
+         <property name="decimals">
+          <number>1</number>
+         </property>
+         <property name="minimum">
+          <double>1.000000000000000</double>
+         </property>
+         <property name="maximum">
+          <double>100000.000000000000000</double>
+         </property>
+        </widget>
+       </item>
       </layout>
      </widget>
      <widget class="QWidget" name="quickview_tab">