Set the limits or the aspect ratio of the current plot.
x A vector of four real numbers or a string.

This function overrides the default mechanism for setting the limits on the current plot. If the input is the string 'square' , limits are forced to be such that one unit along the x-axis is assigned the same number of pixels as a unit along the y-axis . If the input is an array of four numbers, the function sets the limits of the x-axis to be x[1] and x[2] , and those of the y-axis to be x[3] and x[4] .