1 ! Copyright (C) 2008 Eduardo Cavazos.
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: accessors colors kernel math ;
6 TUPLE: gray { gray read-only } { alpha read-only } ;
13 [ gray>> dup dup ] [ alpha>> ] bi <rgba> ; inline
15 M: gray red>> gray>> ;
17 M: gray green>> gray>> ;
19 M: gray blue>> gray>> ;
21 GENERIC: >gray ( color -- gray )
23 M: object >gray >rgba >gray ;
27 [ 0.3 * ] [ 0.59 * ] [ 0.11 * ] tri* + +