
plbox: Draw a box with axes, etc

DESCRIPTION:

	Draws a box around the currently defined viewport, and labels it with
	world coordinate values appropriate to the window.	Thus plbox should
	only be called after defining both viewport and window.  The character
	strings xopt and yopt specify how the box should be drawn as described
	below.	If ticks and/or subticks are to be drawn for a particular
	axis, the tick intervals and number of subintervals may be specified
	explicitly, or they may be defaulted by setting the appropriate
	arguments to zero. 

SYNOPSIS:

plbox(xopt, xtick, nxsub, yopt, ytick, nysub)

ARGUMENTS:

    xopt (const char *, input) :    Pointer to character string specifying
        options for horizontal axis.  The string can include any
        combination of the following letters (upper or lower case) in any
        order: a: Draws axis, X-axis is horizontal line (y=0), and Y-axis
        is vertical line (x=0). 
            b: Draws bottom (X) or left (Y) edge of frame. 
            c: Draws top (X) or right (Y) edge of frame. 
            f:    Always use fixed point numeric labels. 
            g: Draws a grid at the major tick interval. 
            h: Draws a grid at the minor tick interval. 
            i: Inverts tick marks, so they are drawn outwards, rather than
            inwards. 
            l: Labels axis logarithmically.  This only affects the labels,
            not the data, and so it is necessary to compute the logarithms
            of data points before passing them to any of the drawing
            routines. 
            m: Writes numeric labels at major tick intervals in the
            unconventional location (above box for X, right of box for Y). 
            n: Writes numeric labels at major tick intervals in the
            conventional location (below box for X, left of box for Y). 
            s: Enables subticks between major ticks, only valid if t is
            also specified. 
            t: Draws major ticks. 


    xtick (PLFLT, input) :      World coordinate interval between major
        ticks on the x axis. If it is set to zero, PLplot automatically
        generates a suitable tick interval. 

    nxsub (PLINT, input) :      Number of subintervals between major x axis
        ticks for minor ticks.    If it is set to zero, PLplot automatically
        generates a suitable minor tick interval. 

    yopt (const char *, input) :    Pointer to character string specifying
        options for vertical axis.    The string can include any combination
        of the letters defined above for xopt, and in addition may
        contain: v: Write numeric labels for vertical axis parallel to the
        base of the graph, rather than parallel to the axis. 


    ytick (PLFLT, input) :      World coordinate interval between major
        ticks on the y axis. If it is set to zero, PLplot automatically
        generates a suitable tick interval. 

    nysub (PLINT, input) :      Number of subintervals between major y axis
        ticks for minor ticks.    If it is set to zero, PLplot automatically
        generates a suitable minor tick interval. 
