japan.pl

PRl教学程序 PRl教学程序 PRl教学程序

/********************************************************************
    Constraint-based Graphical Programming in B-Prolog
    %
    draw the Japanese flag
*********************************************************************/
go:-
    japan(Os),
    cgJava(japan,Os).

japan([Flag,Frame,Sun]):-
    cgRectangle(Flag), Flag^color #= white,
    cgRectangle(Frame), Frame^color #= black, Frame^fill #= 0,
    cgCircle(Sun), Sun^color #= red,

    cgSamePosition([Frame,Flag]),
    cgSameSize([Frame,Flag]),
    cgSameCenter([Sun,Frame]),

    5*Flag^width #= 7*Flag^height,
    7*Sun^width #= 3*Flag^height.