Beispiel #1
0
class GridView(QListView):

    update_item = pyqtSignal(object)
    files_dropped = pyqtSignal(object)
    books_dropped = pyqtSignal(object)

    def __init__(self, parent):
        QListView.__init__(self, parent)
        self._ncols = None
        self.gesture_manager = GestureManager(self)
        setup_dnd_interface(self)
        self.setUniformItemSizes(True)
        self.setWrapping(True)
        self.setFlow(self.LeftToRight)
        # We cannot set layout mode to batched, because that breaks
        # restore_vpos()
        # self.setLayoutMode(self.Batched)
        self.setResizeMode(self.Adjust)
        self.setSelectionMode(self.ExtendedSelection)
        self.setVerticalScrollMode(self.ScrollPerPixel)
        self.delegate = CoverDelegate(self)
        self.delegate.animation.valueChanged.connect(self.animation_value_changed)
        self.delegate.animation.finished.connect(self.animation_done)
        self.setItemDelegate(self.delegate)
        self.setSpacing(self.delegate.spacing)
        self.set_color()
        self.ignore_render_requests = Event()
        dpr = self.device_pixel_ratio
        self.thumbnail_cache = ThumbnailCache(max_size=gprefs['cover_grid_disk_cache_size'],
            thumbnail_size=(int(dpr * self.delegate.cover_size.width()), int(dpr * self.delegate.cover_size.height())))
        self.render_thread = None
        self.update_item.connect(self.re_render, type=Qt.QueuedConnection)
        self.doubleClicked.connect(self.double_clicked)
        self.setCursor(Qt.PointingHandCursor)
        self.gui = parent
        self.context_menu = None
        self.update_timer = QTimer(self)
        self.update_timer.setInterval(200)
        self.update_timer.timeout.connect(self.update_viewport)
        self.update_timer.setSingleShot(True)
        self.resize_timer = t = QTimer(self)
        t.setInterval(200), t.setSingleShot(True)
        t.timeout.connect(self.update_memory_cover_cache_size)

    def viewportEvent(self, ev):
        try:
            ret = self.gesture_manager.handle_event(ev)
        except AttributeError:
            ret = None
        if ret is not None:
            return ret
        return QListView.viewportEvent(self, ev)

    @property
    def device_pixel_ratio(self):
        try:
            return self.devicePixelRatioF()
        except AttributeError:
            return self.devicePixelRatio()

    @property
    def first_visible_row(self):
        geom = self.viewport().geometry()
        for y in range(geom.top(), (self.spacing()*2) + geom.top(), 5):
            for x in range(geom.left(), (self.spacing()*2) + geom.left(), 5):
                ans = self.indexAt(QPoint(x, y)).row()
                if ans > -1:
                    return ans

    @property
    def last_visible_row(self):
        geom = self.viewport().geometry()
        for y in range(geom.bottom(), geom.bottom() - 2 * self.spacing(), -5):
            for x in range(geom.left(), (self.spacing()*2) + geom.left(), 5):
                ans = self.indexAt(QPoint(x, y)).row()
                if ans > -1:
                    item_width = self.delegate.item_size.width() + 2*self.spacing()
                    return ans + (geom.width() // item_width)

    def update_viewport(self):
        self.ignore_render_requests.clear()
        self.update_timer.stop()
        m = self.model()
        for r in range(self.first_visible_row or 0, self.last_visible_row or (m.count() - 1)):
            self.update(m.index(r, 0))

    def start_view_animation(self, index):
        d = self.delegate
        if d.animating is None and not config['disable_animations']:
            d.animating = index
            d.animation.start()

    def double_clicked(self, index):
        self.start_view_animation(index)
        if tweaks['doubleclick_on_library_view'] == 'open_viewer':
            self.gui.iactions['View'].view_triggered(index)
        elif tweaks['doubleclick_on_library_view'] in {'edit_metadata', 'edit_cell'}:
            self.gui.iactions['Edit Metadata'].edit_metadata(False, False)

    def animation_value_changed(self, value):
        if self.delegate.animating is not None:
            self.update(self.delegate.animating)

    def animation_done(self):
        if self.delegate.animating is not None:
            idx = self.delegate.animating
            self.delegate.animating = None
            self.update(idx)

    def set_color(self):
        r, g, b = gprefs['cover_grid_color']
        pal = QPalette()
        col = QColor(r, g, b)
        pal.setColor(pal.Base, col)
        tex = gprefs['cover_grid_texture']
        if tex:
            from calibre.gui2.preferences.texture_chooser import texture_path
            path = texture_path(tex)
            if path:
                pm = QPixmap(path)
                if not pm.isNull():
                    val = pm.scaled(1, 1).toImage().pixel(0, 0)
                    r, g, b = qRed(val), qGreen(val), qBlue(val)
                    pal.setBrush(pal.Base, QBrush(pm))
        dark = (r + g + b)/3.0 < 128
        pal.setColor(pal.Text, QColor(Qt.white if dark else Qt.black))
        self.setPalette(pal)
        self.delegate.highlight_color = pal.color(pal.Text)

    def refresh_settings(self):
        size_changed = (
            gprefs['cover_grid_width'] != self.delegate.original_width or gprefs['cover_grid_height'] != self.delegate.original_height
        )
        if (size_changed or gprefs[
            'cover_grid_show_title'] != self.delegate.original_show_title or gprefs[
                'show_emblems'] != self.delegate.original_show_emblems or gprefs[
                    'emblem_size'] != self.delegate.orginal_emblem_size or gprefs[
                        'emblem_position'] != self.delegate.orginal_emblem_position):
            self.delegate.set_dimensions()
            self.setSpacing(self.delegate.spacing)
            if size_changed:
                self.delegate.cover_cache.clear()
        if gprefs['cover_grid_spacing'] != self.delegate.original_spacing:
            self.delegate.calculate_spacing()
            self.setSpacing(self.delegate.spacing)
        self.set_color()
        self.set_thumbnail_cache_image_size()
        cs = gprefs['cover_grid_disk_cache_size']
        if (cs*(1024**2)) != self.thumbnail_cache.max_size:
            self.thumbnail_cache.set_size(cs)
        self.update_memory_cover_cache_size()

    def set_thumbnail_cache_image_size(self):
        dpr = self.device_pixel_ratio
        self.thumbnail_cache.set_thumbnail_size(
            int(dpr * self.delegate.cover_size.width()), int(dpr*self.delegate.cover_size.height()))

    def resizeEvent(self, ev):
        self._ncols = None
        self.resize_timer.start()
        return QListView.resizeEvent(self, ev)

    def update_memory_cover_cache_size(self):
        try:
            sz = self.delegate.item_size
        except AttributeError:
            return
        rows, cols = self.width() // sz.width(), self.height() // sz.height()
        num = (rows + 1) * (cols + 1)
        limit = max(100, num * max(2, gprefs['cover_grid_cache_size_multiple']))
        if limit != self.delegate.cover_cache.limit:
            self.delegate.cover_cache.set_limit(limit)

    def shown(self):
        self.update_memory_cover_cache_size()
        if self.render_thread is None:
            self.thumbnail_cache.set_database(self.gui.current_db)
            self.render_thread = Thread(target=self.render_covers)
            self.render_thread.daemon = True
            self.render_thread.start()

    def render_covers(self):
        q = self.delegate.render_queue
        while True:
            book_id = q.get()
            try:
                if book_id is None:
                    return
                if self.ignore_render_requests.is_set():
                    continue
                try:
                    self.render_cover(book_id)
                except:
                    import traceback
                    traceback.print_exc()
            finally:
                q.task_done()

    def render_cover(self, book_id):
        if self.ignore_render_requests.is_set():
            return
        dpr = self.device_pixel_ratio
        page_width = int(dpr * self.delegate.cover_size.width())
        page_height = int(dpr * self.delegate.cover_size.height())
        tcdata, timestamp = self.thumbnail_cache[book_id]
        use_cache = False
        if timestamp is None:
            # Not in cache
            has_cover, cdata, timestamp = self.model().db.new_api.cover_or_cache(book_id, 0)
        else:
            has_cover, cdata, timestamp = self.model().db.new_api.cover_or_cache(book_id, timestamp)
            if has_cover and cdata is None:
                # The cached cover is fresh
                cdata = tcdata
                use_cache = True

        if has_cover:
            p = QImage()
            p.loadFromData(cdata, CACHE_FORMAT if cdata is tcdata else 'JPEG')
            p.setDevicePixelRatio(dpr)
            if p.isNull() and cdata is tcdata:
                # Invalid image in cache
                self.thumbnail_cache.invalidate((book_id,))
                self.update_item.emit(book_id)
                return
            cdata = None if p.isNull() else p
            if not use_cache:  # cache is stale
                if cdata is not None:
                    width, height = p.width(), p.height()
                    scaled, nwidth, nheight = fit_image(
                        width, height, page_width, page_height)
                    if scaled:
                        if self.ignore_render_requests.is_set():
                            return
                        p = p.scaled(nwidth, nheight, Qt.IgnoreAspectRatio, Qt.SmoothTransformation)
                        p.setDevicePixelRatio(dpr)
                    cdata = p
                # update cache
                if cdata is None:
                    self.thumbnail_cache.invalidate((book_id,))
                else:
                    try:
                        self.thumbnail_cache.insert(book_id, timestamp, image_to_data(cdata))
                    except EncodeError as err:
                        self.thumbnail_cache.invalidate((book_id,))
                        prints(err)
                    except Exception:
                        import traceback
                        traceback.print_exc()
        elif tcdata is not None:
            # Cover was removed, but it exists in cache, remove from cache
            self.thumbnail_cache.invalidate((book_id,))
        self.delegate.cover_cache.set(book_id, cdata)
        self.update_item.emit(book_id)

    def re_render(self, book_id):
        self.delegate.cover_cache.clear_staging()
        m = self.model()
        try:
            index = m.db.row(book_id)
        except (IndexError, ValueError, KeyError):
            return
        self.update(m.index(index, 0))

    def shutdown(self):
        self.ignore_render_requests.set()
        self.delegate.render_queue.put(None)
        self.thumbnail_cache.shutdown()

    def set_database(self, newdb, stage=0):
        if stage == 0:
            self.ignore_render_requests.set()
            try:
                for x in (self.delegate.cover_cache, self.thumbnail_cache):
                    self.model().db.new_api.remove_cover_cache(x)
            except AttributeError:
                pass  # db is None
            for x in (self.delegate.cover_cache, self.thumbnail_cache):
                newdb.new_api.add_cover_cache(x)
            try:
                # Use a timeout so that if, for some reason, the render thread
                # gets stuck, we dont deadlock, future covers wont get
                # rendered, but this is better than a deadlock
                join_with_timeout(self.delegate.render_queue)
            except RuntimeError:
                print('Cover rendering thread is stuck!')
            finally:
                self.ignore_render_requests.clear()
        else:
            self.delegate.cover_cache.clear()

    def select_rows(self, rows):
        sel = QItemSelection()
        sm = self.selectionModel()
        m = self.model()
        # Create a range based selector for each set of contiguous rows
        # as supplying selectors for each individual row causes very poor
        # performance if a large number of rows has to be selected.
        for k, g in itertools.groupby(enumerate(rows), lambda i_x:i_x[0]-i_x[1]):
            group = list(map(operator.itemgetter(1), g))
            sel.merge(QItemSelection(m.index(min(group), 0), m.index(max(group), 0)), sm.Select)
        sm.select(sel, sm.ClearAndSelect)

    def selectAll(self):
        # We re-implement this to ensure that only indexes from column 0 are
        # selected. The base class implementation selects all columns. This
        # causes problems with selection syncing, see
        # https://bugs.launchpad.net/bugs/1236348
        m = self.model()
        sm = self.selectionModel()
        sel = QItemSelection(m.index(0, 0), m.index(m.rowCount(QModelIndex())-1, 0))
        sm.select(sel, sm.ClearAndSelect)

    def set_current_row(self, row):
        sm = self.selectionModel()
        sm.setCurrentIndex(self.model().index(row, 0), sm.NoUpdate)

    def set_context_menu(self, menu):
        self.context_menu = menu

    def contextMenuEvent(self, event):
        if self.context_menu is None:
            return
        from calibre.gui2.main_window import clone_menu
        m = clone_menu(self.context_menu) if islinux else self.context_menu
        m.popup(event.globalPos())
        event.accept()

    def get_selected_ids(self):
        m = self.model()
        return [m.id(i) for i in self.selectionModel().selectedIndexes()]

    def restore_vpos(self, vpos):
        self.verticalScrollBar().setValue(vpos)

    def restore_hpos(self, hpos):
        pass

    def handle_mouse_press_event(self, ev):
        if QApplication.keyboardModifiers() & Qt.ShiftModifier:
            # Shift-Click in QListView is broken. It selects extra items in
            # various circumstances, for example, click on some item in the
            # middle of a row then click on an item in the next row, all items
            # in the first row will be selected instead of only items after the
            # middle item.
            index = self.indexAt(ev.pos())
            if not index.isValid():
                return
            ci = self.currentIndex()
            sm = self.selectionModel()
            sm.setCurrentIndex(index, sm.NoUpdate)
            if not ci.isValid():
                return
            if not sm.hasSelection():
                sm.select(index, sm.ClearAndSelect)
                return
            cr = ci.row()
            tgt = index.row()
            top = self.model().index(min(cr, tgt), 0)
            bottom = self.model().index(max(cr, tgt), 0)
            sm.select(QItemSelection(top, bottom), sm.Select)
        else:
            return QListView.mousePressEvent(self, ev)

    def indices_for_merge(self, resolved=True):
        return self.selectionModel().selectedIndexes()

    def number_of_columns(self):
        # Number of columns currently visible in the grid
        if self._ncols is None:
            step = max(10, self.spacing())
            for y in range(step, 500, step):
                for x in range(step, 500, step):
                    i = self.indexAt(QPoint(x, y))
                    if i.isValid():
                        for x in range(self.viewport().width() - step, self.viewport().width() - 300, -step):
                            j = self.indexAt(QPoint(x, y))
                            if j.isValid():
                                self._ncols = j.row() - i.row() + 1
                                return self._ncols
        return self._ncols

    def keyPressEvent(self, ev):
        if handle_enter_press(self, ev, self.start_view_animation, False):
            return
        k = ev.key()
        if ev.modifiers() & Qt.ShiftModifier and k in (Qt.Key_Left, Qt.Key_Right, Qt.Key_Up, Qt.Key_Down):
            ci = self.currentIndex()
            if not ci.isValid():
                return
            c = ci.row()
            delta = {Qt.Key_Left: -1, Qt.Key_Right: 1, Qt.Key_Up: -self.number_of_columns(), Qt.Key_Down: self.number_of_columns()}[k]
            n = max(0, min(c + delta, self.model().rowCount(None) - 1))
            if n == c:
                return
            sm = self.selectionModel()
            rows = {i.row() for i in sm.selectedIndexes()}
            if rows:
                mi, ma = min(rows), max(rows)
                end = mi if c == ma else ma if c == mi else c
            else:
                end = c
            top = self.model().index(min(n, end), 0)
            bottom = self.model().index(max(n, end), 0)
            sm.select(QItemSelection(top, bottom), sm.ClearAndSelect)
            sm.setCurrentIndex(self.model().index(n, 0), sm.NoUpdate)
        else:
            return QListView.keyPressEvent(self, ev)

    @property
    def current_book(self):
        ci = self.currentIndex()
        if ci.isValid():
            try:
                return self.model().db.data.index_to_id(ci.row())
            except (IndexError, ValueError, KeyError, TypeError, AttributeError):
                pass

    def current_book_state(self):
        return self.current_book

    def restore_current_book_state(self, state):
        book_id = state
        self.setFocus(Qt.OtherFocusReason)
        try:
            row = self.model().db.data.id_to_index(book_id)
        except (IndexError, ValueError, KeyError, TypeError, AttributeError):
            return
        self.set_current_row(row)
        self.select_rows((row,))
        self.scrollTo(self.model().index(row, 0), self.PositionAtCenter)

    def marked_changed(self, old_marked, current_marked):
        changed = old_marked | current_marked
        m = self.model()
        for book_id in changed:
            try:
                self.update(m.index(m.db.data.id_to_index(book_id), 0))
            except ValueError:
                pass

    def moveCursor(self, action, modifiers):
        index = QListView.moveCursor(self, action, modifiers)
        if action in (QListView.MoveLeft, QListView.MoveRight) and index.isValid():
            ci = self.currentIndex()
            if ci.isValid() and index.row() == ci.row():
                nr = index.row() + (1 if action == QListView.MoveRight else -1)
                if 0 <= nr < self.model().rowCount(QModelIndex()):
                    index = self.model().index(nr, 0)
        return index

    def selectionCommand(self, index, event):
        if event and event.type() == event.KeyPress and event.key() in (Qt.Key_Home, Qt.Key_End) and event.modifiers() & Qt.CTRL:
            return QItemSelectionModel.ClearAndSelect | QItemSelectionModel.Rows
        return super(GridView, self).selectionCommand(index, event)

    def wheelEvent(self, ev):
        if ev.phase() not in (Qt.ScrollUpdate, 0):
            return
        number_of_pixels = ev.pixelDelta()
        number_of_degrees = ev.angleDelta() / 8.0
        b = self.verticalScrollBar()
        if number_of_pixels.isNull() or islinux:
            # pixelDelta() is broken on linux with wheel mice
            dy = number_of_degrees.y() / 15.0
            # Scroll by approximately half a row
            dy = int(math.ceil((dy) * b.singleStep() / 2.0))
        else:
            dy = number_of_pixels.y()
        if abs(dy) > 0:
            b.setValue(b.value() - dy)

    def paintEvent(self, ev):
        dpr = self.device_pixel_ratio
        page_width = int(dpr * self.delegate.cover_size.width())
        page_height = int(dpr * self.delegate.cover_size.height())
        size_changed = self.thumbnail_cache.set_thumbnail_size(page_width, page_height)
        if size_changed:
            self.delegate.cover_cache.clear()

        return super(GridView, self).paintEvent(ev)
Beispiel #2
0
class GridView(QListView):

    update_item = pyqtSignal(object)
    files_dropped = pyqtSignal(object)
    books_dropped = pyqtSignal(object)

    def __init__(self, parent):
        QListView.__init__(self, parent)
        self._ncols = None
        self.gesture_manager = GestureManager(self)
        setup_dnd_interface(self)
        self.setUniformItemSizes(True)
        self.setWrapping(True)
        self.setFlow(self.LeftToRight)
        # We cannot set layout mode to batched, because that breaks
        # restore_vpos()
        # self.setLayoutMode(self.Batched)
        self.setResizeMode(self.Adjust)
        self.setSelectionMode(self.ExtendedSelection)
        self.setVerticalScrollMode(self.ScrollPerPixel)
        self.delegate = CoverDelegate(self)
        self.delegate.animation.valueChanged.connect(self.animation_value_changed)
        self.delegate.animation.finished.connect(self.animation_done)
        self.setItemDelegate(self.delegate)
        self.setSpacing(self.delegate.spacing)
        self.set_color()
        self.ignore_render_requests = Event()
        dpr = self.device_pixel_ratio
        self.thumbnail_cache = ThumbnailCache(max_size=gprefs['cover_grid_disk_cache_size'],
            thumbnail_size=(int(dpr * self.delegate.cover_size.width()), int(dpr * self.delegate.cover_size.height())))
        self.render_thread = None
        self.update_item.connect(self.re_render, type=Qt.QueuedConnection)
        self.doubleClicked.connect(self.double_clicked)
        self.setCursor(Qt.PointingHandCursor)
        self.gui = parent
        self.context_menu = None
        self.update_timer = QTimer(self)
        self.update_timer.setInterval(200)
        self.update_timer.timeout.connect(self.update_viewport)
        self.update_timer.setSingleShot(True)
        self.resize_timer = t = QTimer(self)
        t.setInterval(200), t.setSingleShot(True)
        t.timeout.connect(self.update_memory_cover_cache_size)

    def viewportEvent(self, ev):
        try:
            ret = self.gesture_manager.handle_event(ev)
        except AttributeError:
            ret = None
        if ret is not None:
            return ret
        return QListView.viewportEvent(self, ev)

    @property
    def device_pixel_ratio(self):
        try:
            return self.devicePixelRatioF()
        except AttributeError:
            return self.devicePixelRatio()

    @property
    def first_visible_row(self):
        geom = self.viewport().geometry()
        for y in range(geom.top(), (self.spacing()*2) + geom.top(), 5):
            for x in range(geom.left(), (self.spacing()*2) + geom.left(), 5):
                ans = self.indexAt(QPoint(x, y)).row()
                if ans > -1:
                    return ans

    @property
    def last_visible_row(self):
        geom = self.viewport().geometry()
        for y in range(geom.bottom(), geom.bottom() - 2 * self.spacing(), -5):
            for x in range(geom.left(), (self.spacing()*2) + geom.left(), 5):
                ans = self.indexAt(QPoint(x, y)).row()
                if ans > -1:
                    item_width = self.delegate.item_size.width() + 2*self.spacing()
                    return ans + (geom.width() // item_width)

    def update_viewport(self):
        self.ignore_render_requests.clear()
        self.update_timer.stop()
        m = self.model()
        for r in range(self.first_visible_row or 0, self.last_visible_row or (m.count() - 1)):
            self.update(m.index(r, 0))

    def start_view_animation(self, index):
        d = self.delegate
        if d.animating is None and not config['disable_animations']:
            d.animating = index
            d.animation.start()

    def double_clicked(self, index):
        self.start_view_animation(index)
        if tweaks['doubleclick_on_library_view'] == 'open_viewer':
            self.gui.iactions['View'].view_triggered(index)
        elif tweaks['doubleclick_on_library_view'] in {'edit_metadata', 'edit_cell'}:
            self.gui.iactions['Edit Metadata'].edit_metadata(False, False)

    def animation_value_changed(self, value):
        if self.delegate.animating is not None:
            self.update(self.delegate.animating)

    def animation_done(self):
        if self.delegate.animating is not None:
            idx = self.delegate.animating
            self.delegate.animating = None
            self.update(idx)

    def set_color(self):
        r, g, b = gprefs['cover_grid_color']
        tex = gprefs['cover_grid_texture']
        pal = self.palette()
        pal.setColor(pal.Base, QColor(r, g, b))
        self.setPalette(pal)
        ss = ''
        if tex:
            from calibre.gui2.preferences.texture_chooser import texture_path
            path = texture_path(tex)
            if path:
                path = os.path.abspath(path).replace(os.sep, '/')
                ss += 'background-image: url({});'.format(path)
                ss += 'background-attachment: fixed;'
                pm = QPixmap(path)
                if not pm.isNull():
                    val = pm.scaled(1, 1).toImage().pixel(0, 0)
                    r, g, b = qRed(val), qGreen(val), qBlue(val)
        dark = max(r, g, b) < 115
        ss += 'color: {};'.format('white' if dark else 'black')
        self.delegate.highlight_color = QColor(Qt.white if dark else Qt.black)
        self.setStyleSheet('QListView {{ {} }}'.format(ss))

    def refresh_settings(self):
        size_changed = (
            gprefs['cover_grid_width'] != self.delegate.original_width or gprefs['cover_grid_height'] != self.delegate.original_height
        )
        if (size_changed or gprefs[
            'cover_grid_show_title'] != self.delegate.original_show_title or gprefs[
                'show_emblems'] != self.delegate.original_show_emblems or gprefs[
                    'emblem_size'] != self.delegate.orginal_emblem_size or gprefs[
                        'emblem_position'] != self.delegate.orginal_emblem_position):
            self.delegate.set_dimensions()
            self.setSpacing(self.delegate.spacing)
            if size_changed:
                self.delegate.cover_cache.clear()
        if gprefs['cover_grid_spacing'] != self.delegate.original_spacing:
            self.delegate.calculate_spacing()
            self.setSpacing(self.delegate.spacing)
        self.set_color()
        self.set_thumbnail_cache_image_size()
        cs = gprefs['cover_grid_disk_cache_size']
        if (cs*(1024**2)) != self.thumbnail_cache.max_size:
            self.thumbnail_cache.set_size(cs)
        self.update_memory_cover_cache_size()

    def set_thumbnail_cache_image_size(self):
        dpr = self.device_pixel_ratio
        self.thumbnail_cache.set_thumbnail_size(
            int(dpr * self.delegate.cover_size.width()), int(dpr*self.delegate.cover_size.height()))

    def resizeEvent(self, ev):
        self._ncols = None
        self.resize_timer.start()
        return QListView.resizeEvent(self, ev)

    def update_memory_cover_cache_size(self):
        try:
            sz = self.delegate.item_size
        except AttributeError:
            return
        rows, cols = self.width() // sz.width(), self.height() // sz.height()
        num = (rows + 1) * (cols + 1)
        limit = max(100, num * max(2, gprefs['cover_grid_cache_size_multiple']))
        if limit != self.delegate.cover_cache.limit:
            self.delegate.cover_cache.set_limit(limit)

    def shown(self):
        self.update_memory_cover_cache_size()
        if self.render_thread is None:
            self.thumbnail_cache.set_database(self.gui.current_db)
            self.render_thread = Thread(target=self.render_covers)
            self.render_thread.daemon = True
            self.render_thread.start()

    def render_covers(self):
        q = self.delegate.render_queue
        while True:
            book_id = q.get()
            try:
                if book_id is None:
                    return
                if self.ignore_render_requests.is_set():
                    continue
                try:
                    self.render_cover(book_id)
                except:
                    import traceback
                    traceback.print_exc()
            finally:
                q.task_done()

    def render_cover(self, book_id):
        if self.ignore_render_requests.is_set():
            return
        dpr = self.device_pixel_ratio
        page_width = int(dpr * self.delegate.cover_size.width())
        page_height = int(dpr * self.delegate.cover_size.height())
        tcdata, timestamp = self.thumbnail_cache[book_id]
        use_cache = False
        if timestamp is None:
            # Not in cache
            has_cover, cdata, timestamp = self.model().db.new_api.cover_or_cache(book_id, 0)
        else:
            has_cover, cdata, timestamp = self.model().db.new_api.cover_or_cache(book_id, timestamp)
            if has_cover and cdata is None:
                # The cached cover is fresh
                cdata = tcdata
                use_cache = True

        if has_cover:
            p = QImage()
            p.loadFromData(cdata, CACHE_FORMAT if cdata is tcdata else 'JPEG')
            p.setDevicePixelRatio(dpr)
            if p.isNull() and cdata is tcdata:
                # Invalid image in cache
                self.thumbnail_cache.invalidate((book_id,))
                self.update_item.emit(book_id)
                return
            cdata = None if p.isNull() else p
            if not use_cache:  # cache is stale
                if cdata is not None:
                    width, height = p.width(), p.height()
                    scaled, nwidth, nheight = fit_image(
                        width, height, page_width, page_height)
                    if scaled:
                        if self.ignore_render_requests.is_set():
                            return
                        p = p.scaled(nwidth, nheight, Qt.IgnoreAspectRatio, Qt.SmoothTransformation)
                        p.setDevicePixelRatio(dpr)
                    cdata = p
                # update cache
                if cdata is None:
                    self.thumbnail_cache.invalidate((book_id,))
                else:
                    try:
                        self.thumbnail_cache.insert(book_id, timestamp, image_to_data(cdata))
                    except EncodeError as err:
                        self.thumbnail_cache.invalidate((book_id,))
                        prints(err)
                    except Exception:
                        import traceback
                        traceback.print_exc()
        elif tcdata is not None:
            # Cover was removed, but it exists in cache, remove from cache
            self.thumbnail_cache.invalidate((book_id,))
        self.delegate.cover_cache.set(book_id, cdata)
        self.update_item.emit(book_id)

    def re_render(self, book_id):
        self.delegate.cover_cache.clear_staging()
        m = self.model()
        try:
            index = m.db.row(book_id)
        except (IndexError, ValueError, KeyError):
            return
        self.update(m.index(index, 0))

    def shutdown(self):
        self.ignore_render_requests.set()
        self.delegate.render_queue.put(None)
        self.thumbnail_cache.shutdown()

    def set_database(self, newdb, stage=0):
        if stage == 0:
            self.ignore_render_requests.set()
            try:
                for x in (self.delegate.cover_cache, self.thumbnail_cache):
                    self.model().db.new_api.remove_cover_cache(x)
            except AttributeError:
                pass  # db is None
            for x in (self.delegate.cover_cache, self.thumbnail_cache):
                newdb.new_api.add_cover_cache(x)
            try:
                # Use a timeout so that if, for some reason, the render thread
                # gets stuck, we dont deadlock, future covers wont get
                # rendered, but this is better than a deadlock
                join_with_timeout(self.delegate.render_queue)
            except RuntimeError:
                print('Cover rendering thread is stuck!')
            finally:
                self.ignore_render_requests.clear()
        else:
            self.delegate.cover_cache.clear()

    def select_rows(self, rows):
        sel = QItemSelection()
        sm = self.selectionModel()
        m = self.model()
        # Create a range based selector for each set of contiguous rows
        # as supplying selectors for each individual row causes very poor
        # performance if a large number of rows has to be selected.
        for k, g in itertools.groupby(enumerate(rows), lambda i_x:i_x[0]-i_x[1]):
            group = list(map(operator.itemgetter(1), g))
            sel.merge(QItemSelection(m.index(min(group), 0), m.index(max(group), 0)), sm.Select)
        sm.select(sel, sm.ClearAndSelect)

    def selectAll(self):
        # We re-implement this to ensure that only indexes from column 0 are
        # selected. The base class implementation selects all columns. This
        # causes problems with selection syncing, see
        # https://bugs.launchpad.net/bugs/1236348
        m = self.model()
        sm = self.selectionModel()
        sel = QItemSelection(m.index(0, 0), m.index(m.rowCount(QModelIndex())-1, 0))
        sm.select(sel, sm.ClearAndSelect)

    def set_current_row(self, row):
        sm = self.selectionModel()
        sm.setCurrentIndex(self.model().index(row, 0), sm.NoUpdate)

    def set_context_menu(self, menu):
        self.context_menu = menu

    def contextMenuEvent(self, event):
        if self.context_menu is None:
            return
        from calibre.gui2.main_window import clone_menu
        m = clone_menu(self.context_menu) if islinux else self.context_menu
        m.popup(event.globalPos())
        event.accept()

    def get_selected_ids(self):
        m = self.model()
        return [m.id(i) for i in self.selectionModel().selectedIndexes()]

    def restore_vpos(self, vpos):
        self.verticalScrollBar().setValue(vpos)

    def restore_hpos(self, hpos):
        pass

    def handle_mouse_press_event(self, ev):
        if QApplication.keyboardModifiers() & Qt.ShiftModifier:
            # Shift-Click in QListView is broken. It selects extra items in
            # various circumstances, for example, click on some item in the
            # middle of a row then click on an item in the next row, all items
            # in the first row will be selected instead of only items after the
            # middle item.
            index = self.indexAt(ev.pos())
            if not index.isValid():
                return
            ci = self.currentIndex()
            sm = self.selectionModel()
            sm.setCurrentIndex(index, sm.NoUpdate)
            if not ci.isValid():
                return
            if not sm.hasSelection():
                sm.select(index, sm.ClearAndSelect)
                return
            cr = ci.row()
            tgt = index.row()
            top = self.model().index(min(cr, tgt), 0)
            bottom = self.model().index(max(cr, tgt), 0)
            sm.select(QItemSelection(top, bottom), sm.Select)
        else:
            return QListView.mousePressEvent(self, ev)

    def indices_for_merge(self, resolved=True):
        return self.selectionModel().selectedIndexes()

    def number_of_columns(self):
        # Number of columns currently visible in the grid
        if self._ncols is None:
            dpr = self.device_pixel_ratio
            width = int(dpr * self.delegate.cover_size.width())
            height = int(dpr * self.delegate.cover_size.height())
            step = max(10, self.spacing())
            for y in range(step, 2 * height, step):
                for x in range(step, 2 * width, step):
                    i = self.indexAt(QPoint(x, y))
                    if i.isValid():
                        for x in range(self.viewport().width() - step, self.viewport().width() - width, -step):
                            j = self.indexAt(QPoint(x, y))
                            if j.isValid():
                                self._ncols = j.row() - i.row() + 1
                                return self._ncols
        return self._ncols

    def keyPressEvent(self, ev):
        if handle_enter_press(self, ev, self.start_view_animation, False):
            return
        k = ev.key()
        if ev.modifiers() & Qt.ShiftModifier and k in (Qt.Key_Left, Qt.Key_Right, Qt.Key_Up, Qt.Key_Down):
            ci = self.currentIndex()
            if not ci.isValid():
                return
            c = ci.row()
            ncols = self.number_of_columns() or 1
            delta = {Qt.Key_Left: -1, Qt.Key_Right: 1, Qt.Key_Up: -ncols, Qt.Key_Down: ncols}[k]
            n = max(0, min(c + delta, self.model().rowCount(None) - 1))
            if n == c:
                return
            sm = self.selectionModel()
            rows = {i.row() for i in sm.selectedIndexes()}
            if rows:
                mi, ma = min(rows), max(rows)
                end = mi if c == ma else ma if c == mi else c
            else:
                end = c
            top = self.model().index(min(n, end), 0)
            bottom = self.model().index(max(n, end), 0)
            sm.select(QItemSelection(top, bottom), sm.ClearAndSelect)
            sm.setCurrentIndex(self.model().index(n, 0), sm.NoUpdate)
        else:
            return QListView.keyPressEvent(self, ev)

    @property
    def current_book(self):
        ci = self.currentIndex()
        if ci.isValid():
            try:
                return self.model().db.data.index_to_id(ci.row())
            except (IndexError, ValueError, KeyError, TypeError, AttributeError):
                pass

    def current_book_state(self):
        return self.current_book

    def restore_current_book_state(self, state):
        book_id = state
        self.setFocus(Qt.OtherFocusReason)
        try:
            row = self.model().db.data.id_to_index(book_id)
        except (IndexError, ValueError, KeyError, TypeError, AttributeError):
            return
        self.set_current_row(row)
        self.select_rows((row,))
        self.scrollTo(self.model().index(row, 0), self.PositionAtCenter)

    def marked_changed(self, old_marked, current_marked):
        changed = old_marked | current_marked
        m = self.model()
        for book_id in changed:
            try:
                self.update(m.index(m.db.data.id_to_index(book_id), 0))
            except ValueError:
                pass

    def moveCursor(self, action, modifiers):
        index = QListView.moveCursor(self, action, modifiers)
        if action in (QListView.MoveLeft, QListView.MoveRight) and index.isValid():
            ci = self.currentIndex()
            if ci.isValid() and index.row() == ci.row():
                nr = index.row() + (1 if action == QListView.MoveRight else -1)
                if 0 <= nr < self.model().rowCount(QModelIndex()):
                    index = self.model().index(nr, 0)
        return index

    def selectionCommand(self, index, event):
        if event and event.type() == event.KeyPress and event.key() in (Qt.Key_Home, Qt.Key_End) and event.modifiers() & Qt.CTRL:
            return QItemSelectionModel.ClearAndSelect | QItemSelectionModel.Rows
        return super(GridView, self).selectionCommand(index, event)

    def wheelEvent(self, ev):
        if ev.phase() not in (Qt.ScrollUpdate, 0):
            return
        number_of_pixels = ev.pixelDelta()
        number_of_degrees = ev.angleDelta() / 8.0
        b = self.verticalScrollBar()
        if number_of_pixels.isNull() or islinux:
            # pixelDelta() is broken on linux with wheel mice
            dy = number_of_degrees.y() / 15.0
            # Scroll by approximately half a row
            dy = int(math.ceil((dy) * b.singleStep() / 2.0))
        else:
            dy = number_of_pixels.y()
        if abs(dy) > 0:
            b.setValue(b.value() - dy)

    def paintEvent(self, ev):
        dpr = self.device_pixel_ratio
        page_width = int(dpr * self.delegate.cover_size.width())
        page_height = int(dpr * self.delegate.cover_size.height())
        size_changed = self.thumbnail_cache.set_thumbnail_size(page_width, page_height)
        if size_changed:
            self.delegate.cover_cache.clear()

        return super(GridView, self).paintEvent(ev)
Beispiel #3
0
class GridView(QListView):

    update_item = pyqtSignal(object)
    files_dropped = pyqtSignal(object)

    def __init__(self, parent):
        QListView.__init__(self, parent)
        setup_dnd_interface(self)
        self.setUniformItemSizes(True)
        self.setWrapping(True)
        self.setFlow(self.LeftToRight)
        # We cannot set layout mode to batched, because that breaks
        # restore_vpos()
        # self.setLayoutMode(self.Batched)
        self.setResizeMode(self.Adjust)
        self.setSelectionMode(self.ExtendedSelection)
        self.setVerticalScrollMode(self.ScrollPerPixel)
        self.delegate = CoverDelegate(self)
        self.delegate.animation.valueChanged.connect(
            self.animation_value_changed)
        self.delegate.animation.finished.connect(self.animation_done)
        self.setItemDelegate(self.delegate)
        self.setSpacing(self.delegate.spacing)
        self.padding_left = 0
        self.set_color()
        self.ignore_render_requests = Event()
        self.thumbnail_cache = ThumbnailCache(
            max_size=gprefs['cover_grid_disk_cache_size'],
            thumbnail_size=(self.delegate.cover_size.width(),
                            self.delegate.cover_size.height()))
        self.render_thread = None
        self.update_item.connect(self.re_render, type=Qt.QueuedConnection)
        self.doubleClicked.connect(self.double_clicked)
        self.setCursor(Qt.PointingHandCursor)
        self.gui = parent
        self.context_menu = None
        self.update_timer = QTimer(self)
        self.update_timer.setInterval(200)
        self.update_timer.timeout.connect(self.update_viewport)
        self.update_timer.setSingleShot(True)

    @property
    def first_visible_row(self):
        geom = self.viewport().geometry()
        for y in xrange(geom.top(), (self.spacing() * 2) + geom.top(), 5):
            for x in xrange(geom.left(), (self.spacing() * 2) + geom.left(),
                            5):
                ans = self.indexAt(QPoint(x, y)).row()
                if ans > -1:
                    return ans

    @property
    def last_visible_row(self):
        geom = self.viewport().geometry()
        for y in xrange(geom.bottom(), geom.bottom() - 2 * self.spacing(), -5):
            for x in xrange(geom.left(), (self.spacing() * 2) + geom.left(),
                            5):
                ans = self.indexAt(QPoint(x, y)).row()
                if ans > -1:
                    item_width = self.delegate.item_size.width(
                    ) + 2 * self.spacing()
                    return ans + (geom.width() // item_width)

    def update_viewport(self):
        self.ignore_render_requests.clear()
        self.update_timer.stop()
        m = self.model()
        for r in xrange(self.first_visible_row or 0, self.last_visible_row
                        or (m.count() - 1)):
            self.update(m.index(r, 0))

    def double_clicked(self, index):
        d = self.delegate
        if d.animating is None and not config['disable_animations']:
            d.animating = index
            d.animation.start()
        if tweaks['doubleclick_on_library_view'] == 'open_viewer':
            self.gui.iactions['View'].view_triggered(index)
        elif tweaks['doubleclick_on_library_view'] in {
                'edit_metadata', 'edit_cell'
        }:
            self.gui.iactions['Edit Metadata'].edit_metadata(False, False)

    def animation_value_changed(self, value):
        if self.delegate.animating is not None:
            self.update(self.delegate.animating)

    def animation_done(self):
        if self.delegate.animating is not None:
            idx = self.delegate.animating
            self.delegate.animating = None
            self.update(idx)

    def set_color(self):
        r, g, b = gprefs['cover_grid_color']
        pal = QPalette()
        col = QColor(r, g, b)
        pal.setColor(pal.Base, col)
        tex = gprefs['cover_grid_texture']
        if tex:
            from calibre.gui2.preferences.texture_chooser import texture_path
            path = texture_path(tex)
            if path:
                pm = QPixmap(path)
                if not pm.isNull():
                    val = pm.scaled(1, 1).toImage().pixel(0, 0)
                    r, g, b = qRed(val), qGreen(val), qBlue(val)
                    pal.setBrush(pal.Base, QBrush(pm))
        dark = (r + g + b) / 3.0 < 128
        pal.setColor(pal.Text, QColor(Qt.white if dark else Qt.black))
        self.setPalette(pal)
        self.delegate.highlight_color = pal.color(pal.Text)

    def refresh_settings(self):
        size_changed = (
            gprefs['cover_grid_width'] != self.delegate.original_width
            or gprefs['cover_grid_height'] != self.delegate.original_height)
        if (size_changed or gprefs['cover_grid_show_title'] !=
                self.delegate.original_show_title):
            self.delegate.set_dimensions()
            self.setSpacing(self.delegate.spacing)
            if size_changed:
                self.delegate.cover_cache.clear()
        if gprefs['cover_grid_spacing'] != self.delegate.original_spacing:
            self.delegate.calculate_spacing()
            self.setSpacing(self.delegate.spacing)
        self.set_color()
        self.delegate.cover_cache.set_limit(gprefs['cover_grid_cache_size'])
        if size_changed:
            self.thumbnail_cache.set_thumbnail_size(
                self.delegate.cover_size.width(),
                self.delegate.cover_size.height())
        cs = gprefs['cover_grid_disk_cache_size']
        if (cs * (1024**2)) != self.thumbnail_cache.max_size:
            self.thumbnail_cache.set_size(cs)

    def shown(self):
        if self.render_thread is None:
            self.thumbnail_cache.set_database(self.gui.current_db)
            self.render_thread = Thread(target=self.render_covers)
            self.render_thread.daemon = True
            self.render_thread.start()

    def render_covers(self):
        q = self.delegate.render_queue
        while True:
            book_id = q.get()
            try:
                if book_id is None:
                    return
                if self.ignore_render_requests.is_set():
                    continue
                try:
                    self.render_cover(book_id)
                except:
                    import traceback
                    traceback.print_exc()
            finally:
                q.task_done()

    def render_cover(self, book_id):
        if self.ignore_render_requests.is_set():
            return
        tcdata, timestamp = self.thumbnail_cache[book_id]
        use_cache = False
        if timestamp is None:
            # Not in cache
            has_cover, cdata, timestamp = self.model(
            ).db.new_api.cover_or_cache(book_id, 0)
        else:
            has_cover, cdata, timestamp = self.model(
            ).db.new_api.cover_or_cache(book_id, timestamp)
            if has_cover and cdata is None:
                # The cached cover is fresh
                cdata = tcdata
                use_cache = True

        if has_cover:
            p = QImage()
            p.loadFromData(cdata, CACHE_FORMAT if cdata is tcdata else 'JPEG')
            if p.isNull() and cdata is tcdata:
                # Invalid image in cache
                self.thumbnail_cache.invalidate((book_id, ))
                self.update_item.emit(book_id)
                return
            cdata = None if p.isNull() else p
            if not use_cache:  # cache is stale
                if cdata is not None:
                    width, height = p.width(), p.height()
                    scaled, nwidth, nheight = fit_image(
                        width, height, self.delegate.cover_size.width(),
                        self.delegate.cover_size.height())
                    if scaled:
                        if self.ignore_render_requests.is_set():
                            return
                        p = p.scaled(nwidth, nheight, Qt.IgnoreAspectRatio,
                                     Qt.SmoothTransformation)
                    cdata = p
                # update cache
                if cdata is None:
                    self.thumbnail_cache.invalidate((book_id, ))
                else:
                    try:
                        self.thumbnail_cache.insert(book_id, timestamp,
                                                    image_to_data(cdata))
                    except EncodeError as err:
                        self.thumbnail_cache.invalidate((book_id, ))
                        prints(err)
                    except Exception:
                        import traceback
                        traceback.print_exc()
        elif tcdata is not None:
            # Cover was removed, but it exists in cache, remove from cache
            self.thumbnail_cache.invalidate((book_id, ))
        self.delegate.cover_cache.set(book_id, cdata)
        self.update_item.emit(book_id)

    def re_render(self, book_id):
        self.delegate.cover_cache.clear_staging()
        m = self.model()
        try:
            index = m.db.row(book_id)
        except (IndexError, ValueError, KeyError):
            return
        self.update(m.index(index, 0))

    def shutdown(self):
        self.ignore_render_requests.set()
        self.delegate.render_queue.put(None)
        self.thumbnail_cache.shutdown()

    def set_database(self, newdb, stage=0):
        if stage == 0:
            self.ignore_render_requests.set()
            try:
                for x in (self.delegate.cover_cache, self.thumbnail_cache):
                    self.model().db.new_api.remove_cover_cache(x)
            except AttributeError:
                pass  # db is None
            for x in (self.delegate.cover_cache, self.thumbnail_cache):
                newdb.new_api.add_cover_cache(x)
            try:
                # Use a timeout so that if, for some reason, the render thread
                # gets stuck, we dont deadlock, future covers wont get
                # rendered, but this is better than a deadlock
                join_with_timeout(self.delegate.render_queue)
            except RuntimeError:
                print('Cover rendering thread is stuck!')
            finally:
                self.ignore_render_requests.clear()
        else:
            self.delegate.cover_cache.clear()

    def select_rows(self, rows):
        sel = QItemSelection()
        sm = self.selectionModel()
        m = self.model()
        # Create a range based selector for each set of contiguous rows
        # as supplying selectors for each individual row causes very poor
        # performance if a large number of rows has to be selected.
        for k, g in itertools.groupby(enumerate(rows), lambda (i, x): i - x):
            group = list(map(operator.itemgetter(1), g))
            sel.merge(
                QItemSelection(m.index(min(group), 0), m.index(max(group), 0)),
                sm.Select)
        sm.select(sel, sm.ClearAndSelect)
Beispiel #4
0
class GridView(QListView):

    update_item = pyqtSignal(object)
    files_dropped = pyqtSignal(object)

    def __init__(self, parent):
        QListView.__init__(self, parent)
        setup_gestures(self)
        setup_dnd_interface(self)
        self.setUniformItemSizes(True)
        self.setWrapping(True)
        self.setFlow(self.LeftToRight)
        # We cannot set layout mode to batched, because that breaks
        # restore_vpos()
        # self.setLayoutMode(self.Batched)
        self.setResizeMode(self.Adjust)
        self.setSelectionMode(self.ExtendedSelection)
        self.setVerticalScrollMode(self.ScrollPerPixel)
        self.delegate = CoverDelegate(self)
        self.delegate.animation.valueChanged.connect(self.animation_value_changed)
        self.delegate.animation.finished.connect(self.animation_done)
        self.setItemDelegate(self.delegate)
        self.setSpacing(self.delegate.spacing)
        self.padding_left = 0
        self.set_color()
        self.ignore_render_requests = Event()
        dpr = self.device_pixel_ratio
        self.thumbnail_cache = ThumbnailCache(max_size=gprefs['cover_grid_disk_cache_size'],
            thumbnail_size=(int(dpr * self.delegate.cover_size.width()), int(dpr * self.delegate.cover_size.height())))
        self.render_thread = None
        self.update_item.connect(self.re_render, type=Qt.QueuedConnection)
        self.doubleClicked.connect(self.double_clicked)
        self.setCursor(Qt.PointingHandCursor)
        self.gui = parent
        self.context_menu = None
        self.update_timer = QTimer(self)
        self.update_timer.setInterval(200)
        self.update_timer.timeout.connect(self.update_viewport)
        self.update_timer.setSingleShot(True)
        self.resize_timer = t = QTimer(self)
        t.setInterval(200), t.setSingleShot(True)
        t.timeout.connect(self.update_memory_cover_cache_size)

    def viewportEvent(self, ev):
        ret = gesture_viewport_event(self, ev)
        if ret is not None:
            return ret
        return QListView.viewportEvent(self, ev)

    @property
    def device_pixel_ratio(self):
        try:
            return self.devicePixelRatioF()
        except AttributeError:
            return self.devicePixelRatio()

    @property
    def first_visible_row(self):
        geom = self.viewport().geometry()
        for y in xrange(geom.top(), (self.spacing()*2) + geom.top(), 5):
            for x in xrange(geom.left(), (self.spacing()*2) + geom.left(), 5):
                ans = self.indexAt(QPoint(x, y)).row()
                if ans > -1:
                    return ans

    @property
    def last_visible_row(self):
        geom = self.viewport().geometry()
        for y in xrange(geom.bottom(), geom.bottom() - 2 * self.spacing(), -5):
            for x in xrange(geom.left(), (self.spacing()*2) + geom.left(), 5):
                ans = self.indexAt(QPoint(x, y)).row()
                if ans > -1:
                    item_width = self.delegate.item_size.width() + 2*self.spacing()
                    return ans + (geom.width() // item_width)

    def update_viewport(self):
        self.ignore_render_requests.clear()
        self.update_timer.stop()
        m = self.model()
        for r in xrange(self.first_visible_row or 0, self.last_visible_row or (m.count() - 1)):
            self.update(m.index(r, 0))

    def double_clicked(self, index):
        d = self.delegate
        if d.animating is None and not config['disable_animations']:
            d.animating = index
            d.animation.start()
        if tweaks['doubleclick_on_library_view'] == 'open_viewer':
            self.gui.iactions['View'].view_triggered(index)
        elif tweaks['doubleclick_on_library_view'] in {'edit_metadata', 'edit_cell'}:
            self.gui.iactions['Edit Metadata'].edit_metadata(False, False)

    def animation_value_changed(self, value):
        if self.delegate.animating is not None:
            self.update(self.delegate.animating)

    def animation_done(self):
        if self.delegate.animating is not None:
            idx = self.delegate.animating
            self.delegate.animating = None
            self.update(idx)

    def set_color(self):
        r, g, b = gprefs['cover_grid_color']
        pal = QPalette()
        col = QColor(r, g, b)
        pal.setColor(pal.Base, col)
        tex = gprefs['cover_grid_texture']
        if tex:
            from calibre.gui2.preferences.texture_chooser import texture_path
            path = texture_path(tex)
            if path:
                pm = QPixmap(path)
                if not pm.isNull():
                    val = pm.scaled(1, 1).toImage().pixel(0, 0)
                    r, g, b = qRed(val), qGreen(val), qBlue(val)
                    pal.setBrush(pal.Base, QBrush(pm))
        dark = (r + g + b)/3.0 < 128
        pal.setColor(pal.Text, QColor(Qt.white if dark else Qt.black))
        self.setPalette(pal)
        self.delegate.highlight_color = pal.color(pal.Text)

    def refresh_settings(self):
        size_changed = (
            gprefs['cover_grid_width'] != self.delegate.original_width or
            gprefs['cover_grid_height'] != self.delegate.original_height
        )
        if (size_changed or gprefs['cover_grid_show_title'] != self.delegate.original_show_title or
                gprefs['show_emblems'] != self.delegate.original_show_emblems or
                gprefs['emblem_size'] != self.delegate.orginal_emblem_size or
                gprefs['emblem_position'] != self.delegate.orginal_emblem_position):
            self.delegate.set_dimensions()
            self.setSpacing(self.delegate.spacing)
            if size_changed:
                self.delegate.cover_cache.clear()
        if gprefs['cover_grid_spacing'] != self.delegate.original_spacing:
            self.delegate.calculate_spacing()
            self.setSpacing(self.delegate.spacing)
        self.set_color()
        if size_changed:
            dpr = self.device_pixel_ratio
            self.thumbnail_cache.set_thumbnail_size(int(dpr * self.delegate.cover_size.width()), int(dpr*self.delegate.cover_size.height()))
        cs = gprefs['cover_grid_disk_cache_size']
        if (cs*(1024**2)) != self.thumbnail_cache.max_size:
            self.thumbnail_cache.set_size(cs)
        self.update_memory_cover_cache_size()

    def resizeEvent(self, ev):
        self.resize_timer.start()
        return QListView.resizeEvent(self, ev)

    def update_memory_cover_cache_size(self):
        try:
            sz = self.delegate.item_size
        except AttributeError:
            return
        rows, cols = self.width() // sz.width(), self.height() // sz.height()
        num = (rows + 1) * (cols + 1)
        limit = max(100, num * max(2, gprefs['cover_grid_cache_size_multiple']))
        if limit != self.delegate.cover_cache.limit:
            self.delegate.cover_cache.set_limit(limit)

    def shown(self):
        self.update_memory_cover_cache_size()
        if self.render_thread is None:
            self.thumbnail_cache.set_database(self.gui.current_db)
            self.render_thread = Thread(target=self.render_covers)
            self.render_thread.daemon = True
            self.render_thread.start()

    def render_covers(self):
        q = self.delegate.render_queue
        while True:
            book_id = q.get()
            try:
                if book_id is None:
                    return
                if self.ignore_render_requests.is_set():
                    continue
                try:
                    self.render_cover(book_id)
                except:
                    import traceback
                    traceback.print_exc()
            finally:
                q.task_done()

    def render_cover(self, book_id):
        if self.ignore_render_requests.is_set():
            return
        tcdata, timestamp = self.thumbnail_cache[book_id]
        use_cache = False
        if timestamp is None:
            # Not in cache
            has_cover, cdata, timestamp = self.model().db.new_api.cover_or_cache(book_id, 0)
        else:
            has_cover, cdata, timestamp = self.model().db.new_api.cover_or_cache(book_id, timestamp)
            if has_cover and cdata is None:
                # The cached cover is fresh
                cdata = tcdata
                use_cache = True

        if has_cover:
            p = QImage()
            p.loadFromData(cdata, CACHE_FORMAT if cdata is tcdata else 'JPEG')
            dpr = self.device_pixel_ratio
            p.setDevicePixelRatio(dpr)
            if p.isNull() and cdata is tcdata:
                # Invalid image in cache
                self.thumbnail_cache.invalidate((book_id,))
                self.update_item.emit(book_id)
                return
            cdata = None if p.isNull() else p
            if not use_cache:  # cache is stale
                if cdata is not None:
                    width, height = p.width(), p.height()
                    scaled, nwidth, nheight = fit_image(
                        width, height, int(dpr * self.delegate.cover_size.width()), int(dpr * self.delegate.cover_size.height()))
                    if scaled:
                        if self.ignore_render_requests.is_set():
                            return
                        p = p.scaled(nwidth, nheight, Qt.IgnoreAspectRatio, Qt.SmoothTransformation)
                        p.setDevicePixelRatio(dpr)
                    cdata = p
                # update cache
                if cdata is None:
                    self.thumbnail_cache.invalidate((book_id,))
                else:
                    try:
                        self.thumbnail_cache.insert(book_id, timestamp, image_to_data(cdata))
                    except EncodeError as err:
                        self.thumbnail_cache.invalidate((book_id,))
                        prints(err)
                    except Exception:
                        import traceback
                        traceback.print_exc()
        elif tcdata is not None:
            # Cover was removed, but it exists in cache, remove from cache
            self.thumbnail_cache.invalidate((book_id,))
        self.delegate.cover_cache.set(book_id, cdata)
        self.update_item.emit(book_id)

    def re_render(self, book_id):
        self.delegate.cover_cache.clear_staging()
        m = self.model()
        try:
            index = m.db.row(book_id)
        except (IndexError, ValueError, KeyError):
            return
        self.update(m.index(index, 0))

    def shutdown(self):
        self.ignore_render_requests.set()
        self.delegate.render_queue.put(None)
        self.thumbnail_cache.shutdown()

    def set_database(self, newdb, stage=0):
        if stage == 0:
            self.ignore_render_requests.set()
            try:
                for x in (self.delegate.cover_cache, self.thumbnail_cache):
                    self.model().db.new_api.remove_cover_cache(x)
            except AttributeError:
                pass  # db is None
            for x in (self.delegate.cover_cache, self.thumbnail_cache):
                newdb.new_api.add_cover_cache(x)
            try:
                # Use a timeout so that if, for some reason, the render thread
                # gets stuck, we dont deadlock, future covers wont get
                # rendered, but this is better than a deadlock
                join_with_timeout(self.delegate.render_queue)
            except RuntimeError:
                print ('Cover rendering thread is stuck!')
            finally:
                self.ignore_render_requests.clear()
        else:
            self.delegate.cover_cache.clear()

    def select_rows(self, rows):
        sel = QItemSelection()
        sm = self.selectionModel()
        m = self.model()
        # Create a range based selector for each set of contiguous rows
        # as supplying selectors for each individual row causes very poor
        # performance if a large number of rows has to be selected.
        for k, g in itertools.groupby(enumerate(rows), lambda (i,x):i-x):
            group = list(map(operator.itemgetter(1), g))
            sel.merge(QItemSelection(m.index(min(group), 0), m.index(max(group), 0)), sm.Select)
        sm.select(sel, sm.ClearAndSelect)