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swi-prologxpce

Depicting a list of objects in XPCE

I want to make an animation in XPCE, consisting of an arbitrary number of moving circles. The circles are given in a Prolog list, containing for each circle its coordinates, radius, and colour. Hence, the list looks like this: [[[1,2],20,red],[[40,2],15,green],...] I can of course generate a circle, name it and colour it as follows:

new(@p,picture).
send(@p,display,new(@ci,circle(20)),point(1,2)).
send(@ci,fill_pattern,colour(red)).

But what do I do when I want to represent the whole list? I would somehow need dynamic names, but things like

send(@p,display,new(@X,circle(20)),point(1,2)).

where X is some identifier specified earlier are not accepted.

Solution

  • Something like that ?

    t1 :-
    L =  [[[1,2],20,red],[[40,2],15,green]] ,
     new(D,picture),
    maplist(my_display(D), L),
    send(D, open).

my_display(D, [[X,Y], R, Colour]) :-
    new(C, circle(R)),
    send(C, fill_pattern, colour(Colour)),
    send(D, display, C, point(X,Y)).