从串口读取数据并将数据绘制成曲线。 封装了一个二维坐标系，横轴和纵轴的范围会随着曲线的数值范围自动伸缩。-To read data from the serial port and the data plotted curves. Encapsulates a two-dimensional coordinate system, the range of the horizontal axis and vertical axis range of values as the curve au