!    NAME
!	screen.pen
!
!    DESCRIPTION
!	This pen table screens or gray shades all reference files based
!	on their attachment order in the IPARM file.  Reference file
!	attachments 1-10 are plotted in one shade, reference file
!	attachments 21-32 are plotted with another shade, and reference
!	file attachements greater than 32 are plotted with yet another
!	shade.  Elements from the master file are plotted as solid black.
!	The reference file elements are set to a weight of 4 (the default
!	pixel threshold in the rendering attributes file) and assigned a
!	priority so that the master file information plots on top of the
!	reference file information.  The weights of the elements in the
!	master file are not modified.
!
!    HISTORY
!	08/09/93 (INGR) Initial creation.


if (file == 0) then		!Test for the master file (attachment 0).
    color = (0,0,0)		!Define the color using RGB values.
    priority = 10
else
    weight = 4                  !Set weight to 4 in order to screen elements
    priority = 0                !Set low priority so that other elements
                                !plot on top
    if (file in 1-10) then
	color = (50,50,50)
    else if (file in 11-20) then
	color = (100,100,100)
    else if (file in 21-32) then
	color = (150,150,150)
    else if (file > 32) then
	color = (200,200,200)
    endif
endif

