Yin and yang: Difference between revisions

=={{header|Prolog}}==

Works with SWI-Prolog and XPCE.

<lang Prolog>ying_yang(N) :-

R is N * 100,

sformat(Title, 'Yin Yang ~w', [N]),

new(W, window(Title)),

new(Wh, colour(@default, 255*255, 255*255, 255*255)),

new(Bl, colour(@default, 0, 0, 0)),

CX is R + 50,

CY is R + 50,

R1 is R / 2,

R2 is R / 8,

CY1 is R1 + 50,

CY2 is 3 * R1 + 50,

new(E, semi_disk(point(CX, CY), R, w, Bl)),

new(F, semi_disk(point(CX, CY), R, e, Wh)),

new(D1, disk(point(CX, CY1), R, Bl)),

new(D2, disk(point(CX, CY2), R, Wh)),

new(D3, disk(point(CX, CY1), R2, Wh)),

new(D4, disk(point(CX, CY2), R2, Bl)),

send_list(W, display, [E, F, D1, D2, D3, D4]),

WD is 2 * R + 100,

send(W, size, size(WD, WD )),

send(W, open).

:- pce_begin_class(semi_disk, path, "Semi disk with color ").

initialise(P, C, R, O, Col) :->

send(P, send_super, initialise),

get(C, x, CX),

get(C, y, CY),

choose(O, Deb, End),

forall(between(Deb, End, I),

( X is R * cos(I * pi/180) + CX,

Y is R * sin(I * pi/180) + CY,

send(P, append, point(X,Y)))),

send(P, closed, @on),

send(P, fill_pattern, Col).

:- pce_end_class.

choose(s, 0, 180).

choose(n, 180, 360).

choose(w, 90, 270).

choose(e, -90, 90).

:- pce_begin_class(disk, ellipse, "disk with color ").

initialise(P, C, R, Col) :->

send(P, send_super, initialise, R, R),

send(P, center, C),

send(P, pen, 0),

send(P, fill_pattern, Col).

:- pce_end_class.

</lang>

Example of output :

<pre> ?- ying_yang(1).

true.

?- ying_yang(2).

true.

</pre>