Veronica Berglyd Olsen
66 lines
2.2 KiB
Python
66 lines
2.2 KiB
Python
"""
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novelWriter – Custom Object: Wheel Event Filter
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===============================================
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File History:
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Created: 2023-08-31 [2.1rc1]
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This file is a part of novelWriter
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Copyright 2018–2023, Veronica Berglyd Olsen
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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"""
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from __future__ import annotations
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from PyQt5.QtGui import QWheelEvent
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from PyQt5.QtCore import QEvent, QObject
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from PyQt5.QtWidgets import QWidget
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class WheelEventFilter(QObject):
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"""Extensions: Wheel Event Filter
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An event filter that filters mouse wheel events for a widget and
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forward them to the root widget. This solves the lack of mouse wheel
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scrolling response in margins of widgets like the editor and viewer.
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Solves: https://github.com/vkbo/novelWriter/issues/1425
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Reference: https://stackoverflow.com/a/17739995/5825851
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"""
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__slots__ = ("_parent", "_locked")
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def __init__(self, parent: QWidget) -> None:
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super().__init__(parent=parent)
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self._parent = parent
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self._locked = False
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return
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def eventFilter(self, object: QObject, event: QEvent) -> bool:
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"""Filter events of type QWheelEvent and forward them to the
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parent widget's wheelEvent handler.
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"""
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if self._locked:
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return False
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if isinstance(event, QWheelEvent):
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# Recursion protection may be redundant, but a comment on
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# StackOverflow points to Qt 5.12 as the change, and we
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# still support Qt 5.10
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self._locked = True
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self._parent.wheelEvent(event)
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self._locked = False
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return False
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# END Class WheelEventFilter
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