class MyGraphicsView(QGraphicsView):

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

        self.scene = QGraphicsScene()
        qImage = QImage(myPixels.data, numColumns, numRows, QImage.Format_Indexed8)
        qImage.setColorTable(self.gray_color_table)
        self.sceneImage = self.scene.addPixmap(QPixmap.fromImage(qImage))

self.fitInView(roiCoords[0], roiCoords[2], roiCoords[1]-roiCoords[0], roiCoords[3]-roiCoords[2], Qt.KeepAspectRatio)