使用qwt实现曲线图区域放大，X\Y轴滚轮放大，X\Y轴单轴放大，在编辑框中输入需要绘制的点数后回车运行。-Use the graph area qwt achieve amplification, X \ Y-axis wheel to zoom in, X \ Y-axis uniaxial enlarge, the transport run after the edit box the number of points need to be drawn.