
plvpor: Specify viewport using coordinates 

DESCRIPTION:

	Device-independent routine for setting up the viewport.  This defines
	the viewport in terms of normalized subpage coordinates which run from
	0.0 to 1.0 (left to right and bottom to top) along each edge of the
	current subpage.  Use the alternate routine plsvpa in order to create
	a viewport of a definite size. 

SYNOPSIS:

plvpor(xmin, xmax, ymin, ymax)

ARGUMENTS:

    xmin (PLFLT, input) :     The normalized subpage coordinate of the
        left-hand edge of the viewport. 

    xmax (PLFLT, input) :     The normalized subpage coordinate of the
        right-hand edge of the viewport. 

    ymin (PLFLT, input) :     The normalized subpage coordinate of the
        bottom edge of the viewport. 

    ymax (PLFLT, input) :     The normalized subpage coordinate of the top
        edge of the viewport. 
