自定义QScrollArea类，使其鼠标可拖拽图片移动

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class myWidgetScrollArea(QScrollArea):
	def __init__(self, father):
		super().__init__()

		self.fatherWidet = father
		self.last_time_move_x = 0
		self.last_time_move_y = 0

		self.scrollBarX = self.horizontalScrollBar()
		self.scrollBarY = self.verticalScrollBar()

	def eventFilter(self, QObject, QEvent):
		if QEvent.type() == QEvent.MouseMove:
			self.fatherWidet.imageLabel.setCursor(QCursor(Qt.SizeAllCursor))	#设置为移动光标样式

			if self.last_time_move_x == 0:
				self.last_time_move_x = QEvent.pos().x()

			if self.last_time_move_y == 0:
				self.last_time_move_y = QEvent.pos().y()

			distance_x = self.last_time_move_x - QEvent.pos().x()
			distance_y = self.last_time_move_y - QEvent.pos().y()

			#print(self.last_time_move_y, QEvent.pos().y(), distance_y, self.scrollBarY.value())
			self.scrollBarX.setValue(self.scrollBarX.value() + distance_x)
			self.scrollBarY.setValue(self.scrollBarY.value() + distance_y)

		elif  QEvent.type() == QEvent.MouseButtonRelease:
			self.last_time_move_x = self.last_time_move_y = 0
			self.fatherWidet.imageLabel.setCursor(QCursor(Qt.PointingHandCursor))		#还原为手型光标样式
		return QWidget.eventFilter(self, QObject, QEvent)