# -*- coding: utf-8 -*- # # This file is part of the qpageview package. # # Copyright (c) 2019 - 2019 by Wilbert Berendsen # # This program is free software; you can redistribute it and/or # modify it under the terms of the GNU General Public License # as published by the Free Software Foundation; either version 2 # of the License, or (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA # See http://www.gnu.org/licenses/ for more information. """ SelectorViewMixin class, to mixin with View. Adds the capability to select or unselect Pages. """ import contextlib from PyQt5.QtCore import pyqtSignal, QRect, Qt from PyQt5.QtGui import QPainter, QKeySequence from PyQt5.QtWidgets import QStyle, QStyleOptionButton class SelectorViewMixin: """SelectorViewMixin class, to mixin with View. Adds the capability to select or unselect Pages. Pages are numbered from 1. Instance variables: ``userChangeSelectionModeEnabled`` = True whether the user can change the selectionMode (by longpressing a page to enable selectionMode, and pressing ESC to leave selectionMode. (Be sure to mix in the :class:`qpageview.util.LongMousePressMixin` class when you want to use the long mouse press event.) """ selectionChanged = pyqtSignal() selectionModeChanged = pyqtSignal(bool) userChangeSelectionModeEnabled = True def __init__(self, parent=None, **kwds): self._selection = set() self._selectionMode = False super().__init__(parent, **kwds) def selection(self): """Return the current list of selected page numbers.""" return sorted(self._selection) @contextlib.contextmanager def modifySelection(self): """Context manager that allows changing the selection. Yields a set, and on exit of the context, stores the modifications and emits the selectionChanged() signal. Used internally by all other methods. """ old = set(self._selection) yield self._selection self._checkSelection() diff = self._selection ^ old if diff: self.selectionChanged.emit() # repaint if needed visible = self.visibleRect() if any(self.page(n).geometry() & visible for n in diff): self.viewport().update() def updatePageLayout(self, lazy=False): """Reimplemented to also check the selection.""" super().updatePageLayout(lazy) self._checkSelection() def _checkSelection(self): """Internal; silently remove page numbers from the selection that do not exist (anymore).""" count = self.pageCount() nums = [n for n in self._selection if n < 1 or n > count] self._selection.difference_update(nums) def clearSelection(self): """Convenience method to clear the selection.""" with self.modifySelection() as s: s.clear() def selectAll(self): """Convenience method to select all pages.""" with self.modifySelection() as s: s.update(range(1, self.pageCount() + 1)) def toggleSelection(self, pageNumber): """Toggles the selected state of page number pageNumber.""" with self.modifySelection() as s: count = len(s) s.add(pageNumber) if count == len(s): s.remove(pageNumber) def selectionMode(self): """Return the current selectionMode (True is enabled, False is disabled).""" return self._selectionMode def setSelectionMode(self, mode): """Switch selection mode on or off (True is enabled, False is disabled).""" if self._selectionMode != mode: self._selectionMode = mode self.selectionModeChanged.emit(mode) self.viewport().update() # repaint def paintEvent(self, ev): super().paintEvent(ev) # first draw the contents if self._selectionMode: painter = QPainter(self.viewport()) for page, rect in self.pagesToPaint(ev.rect(), painter): self.drawSelection(page, painter) def drawSelection(self, page, painter): """Draws the state (selected or not) for the page.""" option = QStyleOptionButton() option.initFrom(self) option.rect = QRect(0, 0, QStyle.PM_IndicatorWidth, QStyle.PM_IndicatorHeight) pageNum = self.pageLayout().index(page) + 1 option.state |= QStyle.State_On if pageNum in self._selection else QStyle.State_Off scale = None # in the unlikely case the checkboxes are larger than the page, scale them down if option.rect not in page.rect(): scale = min(page.width / option.rect.width(), page.height / option.rect.height()) painter.save() painter.scale(scale, scale) self.style().drawPrimitive(QStyle.PE_IndicatorCheckBox, option, painter, self) if scale is not None: painter.restore() def mousePressEvent(self, ev): """Reimplemented to check if a checkbox was clicked.""" if self._selectionMode and ev.buttons() == Qt.LeftButton: pos = ev.pos() - self.layoutPosition() page = self._pageLayout.pageAt(pos) if page: pageNum = self._pageLayout.index(page) + 1 pos -= page.pos() if pos in QRect(0, 0, QStyle.PM_IndicatorWidth, QStyle.PM_IndicatorHeight): # the indicator has been clicked if ev.modifiers() & Qt.ControlModifier: # CTRL toggles selection of page self.toggleSelection(pageNum) elif self._selection and ev.modifiers() & Qt.ShiftModifier: # Shift extends the selection with self.modifySelection() as s: s.add(pageNum) first, last = min(self._selection), max(self._selection) s.update(range(first, last+1)) else: # toggle this one and clear all the others with self.modifySelection() as s: select = pageNum not in s s.clear() if select: s.add(pageNum) return super().mousePressEvent(ev) def keyPressEvent(self, ev): """Clear the selection and switch off selectionmode with ESC.""" if self._selectionMode: if self.userChangeSelectionModeEnabled and ev.key() == Qt.Key_Escape and not ev.modifiers(): self.clearSelection() self.setSelectionMode(False) return elif ev.matches(QKeySequence.SelectAll): self.selectAll() return super().keyPressEvent(ev) def longMousePressEvent(self, ev): """Called on long mouse button press, set selectionMode on if enabled.""" if self.userChangeSelectionModeEnabled: if not self._selectionMode: self.setSelectionMode(True) return elif not self._selection: self.setSelectionMode(False) return super().longMousePressEvent(ev)