Viewer: Add an option to display a scrollbar

src/calibre/gui2/viewer/ui.py

@@ -12,8 +12,8 @@ from hashlib import sha256
 from threading import Thread
 
 from PyQt5.Qt import (
-    QApplication, QDockWidget, QEvent, QMimeData, QModelIndex, QPixmap, Qt, QUrl,
+    QApplication, QDockWidget, QEvent, QHBoxLayout, QMimeData, QModelIndex, QPixmap,
-    QVBoxLayout, QWidget, pyqtSignal
+    QScrollBar, Qt, QUrl, QVBoxLayout, QWidget, pyqtSignal
 )
 
 from calibre import prints
@@ -59,6 +59,61 @@ def path_key(path):
     return sha256(as_bytes(path)).hexdigest()
 
 
+class ScrollBar(QScrollBar):
+
+    def paintEvent(self, ev):
+        if self.isEnabled():
+            return QScrollBar.paintEvent(self, ev)
+
+
+class CentralWidget(QWidget):
+
+    def __init__(self, web_view, parent):
+        QWidget.__init__(self, parent)
+        self.web_view = web_view
+        self.l = l = QHBoxLayout(self)
+        l.setContentsMargins(0, 0, 0, 0), l.setSpacing(0)
+        l.addWidget(web_view)
+        self.vertical_scrollbar = vs = ScrollBar(Qt.Vertical, self)
+        vs.sliderMoved[int].connect(self.slider_moved)
+        l.addWidget(vs)
+        self.current_book_length = None
+        web_view.notify_progress_frac.connect(self.update_scrollbar_positions)
+        web_view.scrollbar_visibility_changed.connect(self.apply_scrollbar_visibility)
+        web_view.overlay_visibility_changed.connect(self.overlay_visibility_changed)
+        self.apply_scrollbar_visibility()
+
+    def apply_scrollbar_visibility(self):
+        visible = get_session_pref('standalone_scrollbar', default=False, group=None)
+        self.vertical_scrollbar.setVisible(bool(visible))
+
+    def overlay_visibility_changed(self, visible):
+        self.vertical_scrollbar.setEnabled(not visible)
+
+    def set_scrollbar_value(self, frac):
+        val = int(self.vertical_scrollbar.maximum() * frac)
+        self.vertical_scrollbar.setValue(val)
+
+    def slider_moved(self, val):
+        frac = val / self.vertical_scrollbar.maximum()
+        self.web_view.goto_frac(frac)
+
+    def initialize_scrollbars(self, book_length):
+        self.current_book_length = book_length
+        maximum = book_length / 10
+        bar = self.vertical_scrollbar
+        bar.setMinimum(0)
+        bar.setMaximum(maximum)
+        bar.setSingleStep(10)
+        bar.setPageStep(100)
+
+    def update_scrollbar_positions(self, progress_frac, file_progress_frac, book_length):
+        if book_length != self.current_book_length:
+            self.initialize_scrollbars(book_length)
+        if not self.vertical_scrollbar.isSliderDown():
+            self.set_scrollbar_value(progress_frac)
+
+
 class EbookViewer(MainWindow):
 
     msg_from_anotherinstance = pyqtSignal(object)
@@ -127,7 +182,8 @@ class EbookViewer(MainWindow):
         self.web_view.selection_changed.connect(self.lookup_widget.selected_text_changed, type=Qt.QueuedConnection)
         self.web_view.view_image.connect(self.view_image, type=Qt.QueuedConnection)
         self.web_view.copy_image.connect(self.copy_image, type=Qt.QueuedConnection)
-        self.setCentralWidget(self.web_view)
+        self.central_widget = CentralWidget(self.web_view, self)
+        self.setCentralWidget(self.central_widget)
         self.restore_state()
         if continue_reading:
             self.continue_reading()
@@ -288,6 +344,7 @@ class EbookViewer(MainWindow):
             self.web_view.show_home_page()
             return
         set_book_path(data['base'], data['pathtoebook'])
+        self.central_widget.initialize_scrollbars(set_book_path.parsed_manifest['spine_length'])
         self.current_book_data = data
         self.current_book_data['annotations_map'] = defaultdict(list)
         self.current_book_data['annotations_path_key'] = path_key(data['pathtoebook']) + '.json'

src/calibre/gui2/viewer/web_view.py

@@ -186,7 +186,7 @@ class UrlSchemeHandler(QWebEngineUrlSchemeHandler):
 
 def get_session_pref(name, default=None, group='standalone_misc_settings'):
     sd = vprefs['session_data']
-    g = sd.get(group, {})
+    g = sd.get(group, {}) if group else sd
     return g.get(name, default)
 
 
@@ -232,6 +232,8 @@ class ViewerBridge(Bridge):
     view_image = from_js(object)
     copy_image = from_js(object)
     change_background_image = from_js(object)
+    notify_progress_frac = from_js(object, object, object)
+    overlay_visibility_changed = from_js(object)
 
     create_view = to_js()
     show_preparing_message = to_js()
@@ -242,6 +244,7 @@ class ViewerBridge(Bridge):
     get_current_cfi = to_js()
     show_home_page = to_js()
     background_image_changed = to_js()
+    goto_frac = to_js()
 
 
 def apply_font_settings(page_or_view):
@@ -373,6 +376,9 @@ class WebView(RestartingWebEngineView):
     selection_changed = pyqtSignal(object)
     view_image = pyqtSignal(object)
     copy_image = pyqtSignal(object)
+    scrollbar_visibility_changed = pyqtSignal()
+    notify_progress_frac = pyqtSignal(object, object, object)
+    overlay_visibility_changed = pyqtSignal(object)
 
     def __init__(self, parent=None):
         self._host_widget = None
@@ -399,6 +405,8 @@ class WebView(RestartingWebEngineView):
         self.bridge.selection_changed.connect(self.selection_changed)
         self.bridge.view_image.connect(self.view_image)
         self.bridge.copy_image.connect(self.copy_image)
+        self.bridge.notify_progress_frac.connect(self.notify_progress_frac)
+        self.bridge.overlay_visibility_changed.connect(self.overlay_visibility_changed)
         self.bridge.report_cfi.connect(self.call_callback)
         self.bridge.change_background_image.connect(self.change_background_image)
         self.pending_bridge_ready_actions = {}
@@ -499,6 +507,8 @@ class WebView(RestartingWebEngineView):
             vprefs['session_data'] = sd
             if key in ('standalone_font_settings', 'base_font_size'):
                 apply_font_settings(self._page)
+            elif key == 'standalone_scrollbar':
+                self.scrollbar_visibility_changed.emit()
 
     def do_callback(self, func_name, callback):
         cid = next(self.callback_id_counter)
@@ -525,3 +535,6 @@ class WebView(RestartingWebEngineView):
                 shutil.copyfileobj(src, dest)
             background_image.ans = None
             self.execute_when_ready('background_image_changed', img_id)
+
+    def goto_frac(self, frac):
+        self.execute_when_ready('goto_frac', frac)

src/calibre/srv/render_book.py

@@ -172,7 +172,7 @@ def get_length(root):
         if elem.tail:
             num += len(strip_space.sub('', elem.tail))
         if tname in 'img svg':
-            num += 2000
+            num += 1000
         return num
 
     for body in root.iterdescendants(XHTML('body')):

src/pyj/read_book/iframe.pyj

@@ -85,6 +85,7 @@ class IframeBoss:
             'initialize':self.initialize,
             'display': self.display,
             'scroll_to_anchor': self.on_scroll_to_anchor,
+            'scroll_to_frac': self.on_scroll_to_frac,
             'next_screen': self.on_next_screen,
             'change_font_size': self.change_font_size,
             'change_color_scheme': self.change_color_scheme,
@@ -105,6 +106,7 @@ class IframeBoss:
         scroll_viewport.update_window_size(data.width, data.height)
         window.onerror = self.onerror
         window.addEventListener('scroll', debounce(self.onscroll, 1000))
+        window.addEventListener('scroll', self.no_latency_onscroll)
         window.addEventListener('resize', debounce(self.onresize, 500))
         window.addEventListener('wheel', self.onwheel, {'passive': False})
         window.addEventListener('keydown', self.onkeydown, {'passive': False})
@@ -171,6 +173,9 @@ class IframeBoss:
         root_data, self.mathjax, self.blob_url_map = finalize_resources(self.book, data.name, data.resource_data)
         self.resource_urls = unserialize_html(root_data, self.content_loaded)
 
+    def on_scroll_to_frac(self, data):
+        self.to_scroll_fraction(data.frac)
+
     def handle_gesture(self, gesture):
         if gesture.type is 'show-chrome':
             self.send_message('show_chrome')
@@ -280,13 +285,13 @@ class IframeBoss:
                 if si:
                     self.length_before += files[si]?.length or 0
         self.onscroll()
-        self.send_message('content_loaded', progress_frac=self.get_progress_frac())
+        self.send_message('content_loaded', progress_frac=self.calculate_progress_frac(), file_progress_frac=progress_frac())
         self.last_cfi = None
         window.setTimeout(self.update_cfi, 0)
         window.setTimeout(self.update_toc_position, 0)
 
-
+    def calculate_progress_frac(self):
-    def calculate_progress_frac(self, current_name, spine_index):
+        current_name = current_spine_item().name
         files = self.book.manifest.files
         file_length = files[current_name]?.length or 0
         if self.length_before is None:
@@ -295,14 +300,6 @@ class IframeBoss:
         ans = (self.length_before + (file_length * frac)) / self.book.manifest.spine_length
         return ans
 
-    def get_progress_frac(self):
-        spine = self.book.manifest.spine
-        current_name = current_spine_item().name
-        index = spine.indexOf(current_name)
-        if index < 0:
-            return 0
-        return self.calculate_progress_frac(current_name, index)
-
     def get_current_cfi(self, data):
         cfi = at_current()
         selected_text = window.getSelection().toString()
@@ -313,7 +310,7 @@ class IframeBoss:
             if index > -1:
                 cfi = 'epubcfi(/{}{})'.format(2*(index+1), cfi)
                 self.send_message(
-                    'report_cfi', cfi=cfi, progress_frac=self.calculate_progress_frac(current_name, index),
+                    'report_cfi', cfi=cfi, progress_frac=self.calculate_progress_frac(),
                     file_progress_frac=progress_frac(), request_id=data.request_id, selected_text=selected_text)
                 return
         self.send_message(
@@ -327,14 +324,18 @@ class IframeBoss:
             index = spine.indexOf(current_name)
             if index > -1:
                 cfi = 'epubcfi(/{}{})'.format(2*(index+1), cfi)
+                pf = self.calculate_progress_frac()
+                fpf = progress_frac()
                 if cfi is not self.last_cfi:
                     self.last_cfi = cfi
                     selected_text = window.getSelection().toString()
                     self.send_message(
                         'update_cfi', cfi=cfi, replace_history=self.replace_history_on_next_cfi_update,
-                        progress_frac=self.calculate_progress_frac(current_name, index),
+                        progress_frac=pf, file_progress_frac=fpf, selected_text=selected_text)
-                        file_progress_frac=progress_frac(), selected_text=selected_text)
                     self.replace_history_on_next_cfi_update = True
+                else:
+                    self.send_message(
+                        'update_progress_frac', progress_frac=pf, file_progress_frac=fpf)
 
     def update_toc_position(self):
         visible_anchors = update_visible_toc_anchors(self.book.manifest.toc_anchor_map, self.anchor_funcs)
@@ -345,6 +346,12 @@ class IframeBoss:
             self.update_cfi()
             self.update_toc_position()
 
+    def no_latency_onscroll(self):
+        pf = self.calculate_progress_frac()
+        fpf = progress_frac()
+        self.send_message(
+            'update_progress_frac', progress_frac=pf, file_progress_frac=fpf)
+
     def onresize(self):
         self.send_message('request_size')
         if self.content_ready:

src/pyj/read_book/prefs/scrolling.pyj

@@ -10,6 +10,8 @@ from dom import unique_id
 from widgets import create_button
 from session import defaults
 
+from read_book.globals import runtime
+
 CONTAINER = unique_id('standalone-scrolling-settings')
 
 
@@ -41,6 +43,11 @@ def create_scrolling_panel(container):
     container.appendChild(cb(
         'paged_margin_clicks_scroll_by_screen', _('Clicking on the margins scrolls by screen fulls instead of pages')))
 
+    if runtime.is_standalone_viewer:
+        container.appendChild(E.div(style='margin-top:1ex; border-top: solid 1px', '\xa0'))
+        container.appendChild(cb(
+            'standalone_scrollbar', _('Show a scrollbar')))
+
     container.appendChild(E.div(
         style='margin-top: 1rem', create_button(_('Restore defaults'), action=restore_defaults)
     ))

src/pyj/read_book/view.pyj

@@ -186,6 +186,7 @@ class View:
             'goto_doc_boundary': def(data): self.goto_doc_boundary(data.start);,
             'scroll_to_anchor': self.on_scroll_to_anchor,
             'update_cfi': self.on_update_cfi,
+            'update_progress_frac': self.on_update_progress_frac,
             'report_cfi': self.on_report_cfi,
             'update_toc_position': self.on_update_toc_position,
             'content_loaded': self.on_content_loaded,
@@ -288,6 +289,8 @@ class View:
     def overlay_visibility_changed(self, visible):
         if self.iframe_wrapper.send_message:
             self.iframe_wrapper.send_message('set_forward_keypresses', forward=v'!!visible')
+        if ui_operations.overlay_visibility_changed:
+            ui_operations.overlay_visibility_changed(visible)
 
     def on_handle_shortcut(self, data):
         if data.name is 'back':
@@ -621,6 +624,34 @@ class View:
         name = self.book.manifest.spine[0 if start else self.book.manifest.spine.length - 1]
         self.show_name(name, initial_position={'type':'frac', 'frac':0 if start else 1, 'replace_history':False})
 
+    def goto_frac(self, frac):
+        if not self.book or not self.book.manifest:
+            return
+        chapter_start_page = 0
+        total_length = self.book.manifest.spine_length
+        page = total_length * frac
+        chapter_frac = 0
+        chapter_name = None
+        for name in self.book.manifest.spine:
+            chapter_length = self.book.manifest.files[name]?.length or 0
+            chapter_end_page = chapter_start_page + chapter_length
+            if chapter_start_page <= page <= chapter_end_page:
+                num_pages = chapter_end_page - chapter_start_page - 1
+                if num_pages > 0:
+                    chapter_frac = (page - chapter_start_page) / num_pages
+                else:
+                    chapter_frac = 0
+                chapter_name = name
+                break
+            chapter_start_page = chapter_end_page
+        if not chapter_name:
+            chapter_name = self.book.manifest.spine[-1]
+        chapter_frac = max(0, min(chapter_frac, 1))
+        if self.currently_showing.name is chapter_name:
+            self.iframe_wrapper.send_message('scroll_to_frac', frac=chapter_frac)
+        else:
+            self.show_name(chapter_name, initial_position={'type':'frac', 'frac':chapter_frac, 'replace_history':True})
+
     def on_scroll_to_anchor(self, data):
         self.show_name(data.name, initial_position={'type':'anchor', 'anchor':data.frag, 'replace_history':False})
 
@@ -698,8 +729,7 @@ class View:
         if not self.book.last_read_position:
             self.book.last_read_position = {}
         self.book.last_read_position[unkey] = data.cfi
-        self.current_progress_frac = data.progress_frac
+        self.set_progress_frac(data.progress_frac, data.file_progress_frac)
-        self.current_file_progress_frac = data.file_progress_frac
         self.update_header_footer()
         if ui_operations.update_last_read_time:
             ui_operations.update_last_read_time(self.book)
@@ -716,6 +746,10 @@ class View:
             })
             v'delete self.report_cfi_callbacks[data.request_id]'
 
+    def on_update_progress_frac(self, data):
+        self.set_progress_frac(data.progress_frac, data.file_progress_frac)
+        self.update_header_footer()
+
     def on_update_cfi(self, data):
         overlay_shown = not self.processing_spine_item_display and self.overlay.is_visible
         if overlay_shown or self.search_overlay.is_visible or self.content_popup_overlay.is_visible:
@@ -741,7 +775,7 @@ class View:
         has_clock = False
 
         if self.book?.manifest:
-            book_length = self.book.manifest.total_length or 0
+            book_length = self.book.manifest.spine_length or 0
             name = self.currently_showing.name
             chapter_length = self.book.manifest.files[name]?.length or 0
         else:
@@ -815,11 +849,19 @@ class View:
     def on_content_loaded(self, data):
         self.processing_spine_item_display = False
         self.hide_loading()
-        frac = data.progress_frac or 0
+        self.set_progress_frac(data.progress_frac, data.file_progress_frac)
-        self.current_progress_frac = frac
         self.update_header_footer()
         window.scrollTo(0, 0)  # ensure window is at 0 on mobile where the navbar causes issues
 
+    def set_progress_frac(self, progress_frac, file_progress_frac):
+        self.current_progress_frac = progress_frac or 0
+        self.current_file_progress_frac = file_progress_frac or 0
+        if ui_operations.notify_progress_frac:
+            book_length = 0
+            if self.book?.manifest:
+                book_length = self.book.manifest.spine_length or 0
+            ui_operations.notify_progress_frac(self.current_progress_frac, self.current_file_progress_frac, book_length)
+
     def update_font_size(self):
         self.iframe_wrapper.send_message('change_font_size', base_font_size=get_session_data().get('base_font_size'))
 

src/pyj/session.pyj

@@ -48,6 +48,7 @@ defaults = {
     'keyboard_shortcuts': {},
     'standalone_font_settings': {},
     'standalone_misc_settings': {},
+    'standalone_scrollbar': False,
     'standalone_recently_opened': v'[]',
     'paged_wheel_scrolls_by_screen': False,
     'paged_margin_clicks_scroll_by_screen': True,
@@ -72,6 +73,7 @@ is_local_setting = {
     'standalone_font_settings': True,
     'standalone_misc_settings': True,
     'standalone_recently_opened': True,
+    'standalone_scrollbar': False,
 }
 
 

src/pyj/viewer-main.pyj

@@ -237,6 +237,12 @@ def get_current_cfi(request_id):
     view.get_current_cfi(request_id, ui_operations.report_cfi)
 
 
+@from_python
+def goto_frac(frac):
+    if view:
+        view.goto_frac(frac)
+
+
 @from_python
 def background_image_changed(img_id):
     img = document.getElementById(img_id)
@@ -306,8 +312,12 @@ if window is window.top:
         to_python.copy_image(name)
     ui_operations.change_background_image = def(img_id):
         to_python.change_background_image(img_id)
+    ui_operations.notify_progress_frac = def (pf, fpf, book_length):
+        to_python.notify_progress_frac(pf, fpf, book_length)
     ui_operations.quit = def():
         to_python.quit()
+    ui_operations.overlay_visibility_changed = def(visible):
+        to_python.overlay_visibility_changed(visible)
 
     document.body.appendChild(E.div(id='view'))
     window.onerror = onerror