帮我重写graphicsview类，并重写鼠标事件，实现调整鼠标拖动目标并能拉伸大小

以下是重写的GraphicsView类及鼠标事件：

class GraphicsView(QtWidgets.QGraphicsView):
    def __init__(self, parent=None):
        super(GraphicsView, self).__init__(parent)
        self.setDragMode(QtWidgets.QGraphicsView.RubberBandDrag)
        self.setRenderHint(QtGui.QPainter.Antialiasing, True)
        self.setRenderHint(QtGui.QPainter.SmoothPixmapTransform, True)
        self.setResizeAnchor(QtWidgets.QGraphicsView.AnchorUnderMouse)
        self.setTransformationAnchor(QtWidgets.QGraphicsView.AnchorUnderMouse)

        self.current_item = None
        self.resize_direction = None
        self.resize_threshold = 10

    def mousePressEvent(self, event: QtGui.QMouseEvent) -> None:
        super(GraphicsView, self).mousePressEvent(event)
        self.current_item = None
        self.resize_direction = None

        items = self.items(event.pos())
        for item in items:
            if isinstance(item, QtWidgets.QGraphicsRectItem):
                self.current_item = item
                rect = item.rect()
                if rect.top() + self.resize_threshold >= event.pos().y():
                    if rect.left() + self.resize_threshold >= event.pos().x():
                        self.resize_direction = "top_left"
                    elif rect.right() - self.resize_threshold <= event.pos().x():
                        self.resize_direction = "top_right"
                    else:
                        self.resize_direction = "top"
                elif rect.bottom() - self.resize_threshold <= event.pos().y():
                    if rect.left() + self.resize_threshold >= event.pos().x():
                        self.resize_direction = "bottom_left"
                    elif rect.right() - self.resize_threshold <= event.pos().x():
                        self.resize_direction = "bottom_right"
                    else:
                        self.resize_direction = "bottom"
                elif rect.left() + self.resize_threshold >= event.pos().x():
                    self.resize_direction = "left"
                elif rect.right() - self.resize_threshold <= event.pos().x():
                    self.resize_direction = "right"

    def mouseMoveEvent(self, event: QtGui.QMouseEvent) -> None:
        super(GraphicsView, self).mouseMoveEvent(event)
        if self.current_item:
            rect = self.current_item.rect()
            dx = event.pos().x() - event.lastPos().x()
            dy = event.pos().y() - event.lastPos().y()

            if self.resize_direction == "top_left":
                rect.setTop(rect.top() + dy)
                rect.setLeft(rect.left() + dx)
            elif self.resize_direction == "top_right":
                rect.setTop(rect.top() + dy)
                rect.setRight(rect.right() + dx)
            elif self.resize_direction == "top":
                rect.setTop(rect.top() + dy)
            elif self.resize_direction == "bottom_left":
                rect.setBottom(rect.bottom() + dy)
                rect.setLeft(rect.left() + dx)
            elif self.resize_direction == "bottom_right":
                rect.setBottom(rect.bottom() + dy)
                rect.setRight(rect.right() + dx)
            elif self.resize_direction == "bottom":
                rect.setBottom(rect.bottom() + dy)
            elif self.resize_direction == "left":
                rect.setLeft(rect.left() + dx)
            elif self.resize_direction == "right":
                rect.setRight(rect.right() + dx)

            self.current_item.setRect(rect)

    def mouseReleaseEvent(self, event: QtGui.QMouseEvent) -> None:
        super(GraphicsView, self).mouseReleaseEvent(event)
        self.current_item = None
        self.resize_direction = None

这个类继承自QGraphicsView，并在mousePressEvent、mouseMoveEvent和mouseReleaseEvent方法中重新实现了鼠标事件，以实现调整鼠标拖动目标并能拉伸大小的功能。

在mousePressEvent方法中，我们检查鼠标是否按下了一个矩形项。如果是，我们将该项设置为当前项，并检查鼠标指针是否在项的边界上。如果是，我们将resize_direction设置为相应的方向。

在mouseMoveEvent方法中，如果我们有一个当前项和resize_direction，则我们使用鼠标移动的距离来调整项的大小和位置。

在mouseReleaseEvent方法中，我们清除当前项和resize_direction，以便下一次鼠标事件可以重新开始。