plsdiplz: Set parameters incrementally (zoom mode) that define current plot-space window 

DESCRIPTION:

    Set relative minima and maxima incrementally (zoom mode) that define
    the current plot-space window.  This function has the same effect as
    plsdiplt if that function has not been previously called.  Otherwise,
    this function implements zoom mode using the transformation min_used =
    old_min + old_length*min  and max_used = old_min + old_length*max  for
    each axis.	For example, if min = 0.05 and max = 0.95 for each axis,
    repeated calls to plsdiplz will zoom in by 10 per cent for each call. 

SYNOPSIS:

plsdiplz(xmin, ymin, xmax, ymax)

ARGUMENTS:

    xmin (PLFLT, input) :    Relative (incremental) minimum in x. 

    ymin (PLFLT, input) :    Relative (incremental) minimum in y. 

    xmax (PLFLT, input) :    Relative (incremental) maximum in x. 

    ymax (PLFLT, input) :    Relative (incremental) maximum in y.