pro fixclrtab
;
; Insure that current color table has bottom index black (for backgrounds),
;   and top index white, for text, lines, etc (!p.color)
; Note bytscl'ing of data must use bytscl(...top=!p.table_size-3...)+1
;   to avoid using the black and white indices in the data
;
tvlct,r,g,b,/get
nc = !d.table_size
r(0) = 0
g(0) = 0
b(0) = 0
r(nc-1) = 255
g(nc-1) = 255
b(nc-1) = 255
tvlct,r,g,b
return
end