A scrollable tooltip in PyQt (PySide6)

main.py

import sys
from typing import cast

from lorem_text import lorem

from PySide6 import QtCore
from PySide6.QtCore import QSize, Qt, QPoint, QEvent, QPropertyAnimation, QEasingCurve, QObject
from PySide6.QtGui import QHelpEvent, QPalette, QKeyEvent, QMouseEvent, QScreen, QGuiApplication
from PySide6.QtWidgets import QApplication, QMainWindow, QPushButton, QScrollArea, QWidget, QVBoxLayout, QLabel, QGraphicsOpacityEffect, QToolTip, \
    QFrame


def get_widget_screen(pos: QPoint, widget: QWidget) -> QScreen:
    guess = widget.screen() if widget else QGuiApplication.primaryScreen()
    exact = guess.virtualSiblingAt(pos)
    return exact or guess


class ScrollableToolTip(QScrollArea):

    def __init__(self, parent: QWidget = None):
        super().__init__(parent)

        self.animations = None
        self.label_eff = None
        self.setWidgetResizable(True)

        self.label = QLabel(self)
        self.label.setAlignment(Qt.AlignLeft | Qt.AlignTop)
        self.label.setWordWrap(True)
        self.setWidget(self.label)

        self.setWindowFlags(Qt.ToolTip | Qt.BypassGraphicsProxyWidget)
        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOn)
        self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.setFixedHeight(100)
        self.setMouseTracking(True)

        self.setForegroundRole(QPalette.ToolTipText)
        self.setBackgroundRole(QPalette.ToolTipBase)
        self.setPalette(QToolTip.palette())
        self.ensurePolished()
        self.setFrameStyle(QFrame.NoFrame)
        self.setAlignment(Qt.AlignLeft)

    def event(self, event: QEvent) -> bool:
        if event.type() in [QEvent.KeyPress, QEvent.KeyRelease]:
            key = cast(QKeyEvent, event).key()
            if key < Qt.Key_Shift or key > Qt.Key_ScrollLock:
                self.hide()
        elif event.type() == QEvent.Leave:
            self.fade_out()
        elif event.type() == QEvent.MouseMove:
            if not self.rect().isNull() and not self.rect().contains(cast(QMouseEvent, event).globalPos().toPoint()):
                self.fade_out()
        return super().event(event)

    def set_text(self, text: str):
        self.label.setText(text)

    def show_at(self, pos: QPoint):
        self.show()
        self.move(pos)

    def fade_out(self):
        """Fades out both the label and the window for 500ms"""
        self.label_eff = QGraphicsOpacityEffect(self)
        self.label.setGraphicsEffect(self.label_eff)

        self.animations = [
            QPropertyAnimation(self.label_eff, b"opacity"),
            QPropertyAnimation(self, b"windowOpacity")
        ]
        for animation in self.animations:
            animation.setDuration(500)
            animation.setStartValue(1)
            animation.setEndValue(0)
            animation.setEasingCurve(QEasingCurve.OutBack)
            animation.start(QPropertyAnimation.DeleteWhenStopped)
            animation.finished.connect(self.hide)  # type: ignore

    def place_tooltip(self, pos: QPoint, widget: QWidget):
        """A pyside6 compatible implementation of QTipLabel::placeTip

        Skips the steps related to QPlatformScreen because that isn't exposed
        in the PyQt/PySide implementation of Qt
        """
        self.show()
        screen = get_widget_screen(pos, widget)
        screen_rect = screen.geometry()
        if pos.x() + self.width() > screen_rect.x() + screen_rect.width():
            pos.setX(
                pos.x() - (4 + self.width())  # rx() -=
            )
        if pos.y() + self.height() > screen_rect.y() + screen_rect.width():
            pos.setY(
                pos.y() - (24 + self.height())  # ry() -=
            )
        if pos.y() < screen_rect.y():
            pos.setY(screen_rect.y())
        if pos.x() + self.width() > screen_rect.x() + screen_rect.width():
            pos.setX(
                screen_rect.x() + screen_rect.width() - self.width()
            )
        if pos.x() < screen_rect.x():
            pos.setX(
                screen_rect.x()
            )
        if pos.y() + self.height() > screen_rect.y() + screen_rect.height():
            pos.setY(
                screen_rect.y() + screen_rect.height() - self.height()
            )
        self.move(pos)


class CustomButton(QPushButton):
    def event(self, e: QtCore.QEvent) -> bool:
        if QtCore.QEvent.ToolTip == e.type():
            e = cast(QHelpEvent, e)
            tooltip = ScrollableToolTip(self)
            tooltip.set_text(self.toolTip())
            tooltip.place_tooltip(e.globalPos(), self)
            return False
        return super().event(e)


class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()

        self.setWindowTitle("My App")

        button = CustomButton("Hover over Me!", parent=self)
        button.setToolTip(lorem.paragraphs(30))

        self.setFixedSize(QSize(400, 300))

        self.setCentralWidget(button)


if __name__ == '__main__':
    app = QApplication(sys.argv)

    window = MainWindow()
    window.show()

    app.exec()