Table Widget with Cells Resizable by Mouse

import sys
from typing import cast

from PySide6.QtCore import QEvent, QObject, QPointF, Qt
from PySide6.QtGui import QMouseEvent
from PySide6.QtWidgets import QApplication, QTableWidget, QWidget


class ResizableTableWidget(QTableWidget):
    _grab_tol: float = 4.0

    def __init__(
            self,
            /,
            parent: QWidget | None = None,
            *,
            rowCount: int | None = None,
            columnCount: int | None = None,
    ) -> None:
        super().__init__(parent, rowCount=rowCount, columnCount=columnCount)

        self.horizontalHeader().hide()
        self.verticalHeader().hide()

        self._col_to_resize: int | None = None
        self._row_to_resize: int | None = None

        QApplication.instance().installEventFilter(self)

    def eventFilter(self, o: QObject, event: QEvent, /) -> bool:
        if o is not self.viewport():
            return False

        match event.type():
            case QEvent.Type.MouseMove:
                pos: QPointF = cast(QMouseEvent, event).position()
                x: float = pos.x()
                y: float = pos.y()

                col: bool = self.columnAt(round(x - ResizableTableWidget._grab_tol)) != self.columnAt(
                    round(x + ResizableTableWidget._grab_tol)
                )
                row: bool = self.rowAt(round(y - ResizableTableWidget._grab_tol)) != self.rowAt(
                    round(y + ResizableTableWidget._grab_tol)
                )
                if col and row:
                    self.setCursor(Qt.CursorShape.SizeAllCursor)
                elif col:
                    self.setCursor(Qt.CursorShape.SizeHorCursor)
                elif row:
                    self.setCursor(Qt.CursorShape.SizeVerCursor)
                else:
                    self.unsetCursor()

                if cast(QMouseEvent, event).buttons() != Qt.MouseButton.LeftButton:
                    return False

                if self._col_to_resize is not None:
                    if (
                            abs(sum(self.columnWidth(i) for i in range(self._col_to_resize + 1)) - x)
                            > ResizableTableWidget._grab_tol / 4
                    ):
                        self.setColumnWidth(
                            self._col_to_resize,
                            round(x - sum(self.columnWidth(i) for i in range(self._col_to_resize))),
                        )
                        self.updateGeometries()
                if self._row_to_resize is not None:
                    if (
                            abs(sum(self.rowHeight(i) for i in range(self._row_to_resize + 1)) - y)
                            > ResizableTableWidget._grab_tol / 4
                    ):
                        self.setRowHeight(
                            self._row_to_resize,
                            round(y - sum(self.rowHeight(i) for i in range(self._row_to_resize))),
                        )
                        self.updateGeometries()

            case QEvent.Type.MouseButtonPress:
                if cast(QMouseEvent, event).buttons() != Qt.MouseButton.LeftButton:
                    return False

                pos: QPointF = cast(QMouseEvent, event).position()
                x: float = pos.x()
                y: float = pos.y()

                if self.columnAt(round(x - ResizableTableWidget._grab_tol)) != self.columnAt(
                        round(x + ResizableTableWidget._grab_tol)
                ):
                    self._col_to_resize = self.columnAt(round(x - ResizableTableWidget._grab_tol))
                if self.rowAt(round(y - ResizableTableWidget._grab_tol)) != self.rowAt(
                        round(y + ResizableTableWidget._grab_tol)
                ):
                    self._row_to_resize = self.rowAt(round(y - ResizableTableWidget._grab_tol))

            case QEvent.Type.MouseButtonRelease:
                self._col_to_resize = None
                self._row_to_resize = None

        return False


if __name__ == "__main__":
    QApplication(sys.argv)
    t: ResizableTableWidget = ResizableTableWidget(rowCount=4, columnCount=3)
    t.show()
    QApplication.exec()