说明：  本函数目的是把 matlab 做的图坐标轴移到图形的中间部分去(与数学的做图习惯一致)，并可以实现matlab动态保存tif图片。 The purpose of this function is to move the matlab do figure axis to the middle part of the graphics (in accordance with mathematical figure used to do), and can realize the matlab dynamic save tif images.