: (fill- ( frame grid-layout quot1 quot2 -- pref-dim gap filled-cell dims )
[ '[ [ dim>> ] [ gap>> ] [ filled-cell>> ] tri _ tri@ ] dip ] dip call ; inline
-: available-space ( pref-dim gap dims -- avail )
- length 1+ * [-] ; inline
-
: -center) ( pref-dim gap filled-cell dims -- )
[ nip available-space ] 2keep [ remove-nth sum [-] ] 2keep set-nth ; inline