I’m going to write a simple animation in XPCE ( four glasses puzzle to

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Asked: May 19, 20262026-05-19T12:10:37+00:00 2026-05-19T12:10:37+00:00

I’m going to write a simple animation in XPCE ( four glasses puzzle to

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I’m going to write a simple animation in XPCE (four glasses puzzle to be precise). I know absolutely nothing about XPCE so I looked up a tutorial but the results are disappointing. Could anyone point me to some materials on the following:

working with a “canvas”
animation
timers

EDIT: Okay, here’s a more detailed problem: I want to draw two boxes, wait two seconds, hide the boxes, then start a timer.

new(@box1, box(100,100)),
send(W, display, @box1),
new(@box2, box(100,100)),
send(W, display, @box2, point(200, 200)),

% wait two seconds here
% hide the boxes here

new(Msg1, and(message(B1, relative_move, point(5, 0)),
              message(B4, relative_move, point(0, 5)))),
send(W, attribute, attribute(timer, new(T, timer(0.1, Msg1)))),

send(T, start),

EDIT 2: Okay, here is another question (should I open a new question?): This is the code I’m using:

get_file(0, 'glass.gif').
get_file(180, 'glass180.gif').

main(GA, GB, GC, GD) :- % e.g. main(0,0,180,0).
    new(B1, figure),
    get_file(GA, G1),
    send(B1, display, new(BM1, bitmap(G1))),
    send(BM1, transparent, @on),
    send(W, display, B1, point(0,0)),     

%analogically for the other three glasses

I’d like to set a new bitmap for B1. How do I do that? Would altering BM1 be enough? Or perhaps there is an alternative solution? I’ve been thinking about drawing both upright and reversed glasses off-screen and swapping them, but I’m not sure about the details of such solution.

EDIT2′: Solved it. For posterity:

send(B1, clear),
send(B1, display, bitmap('glass_while_animating_1.gif')),
send(timer(0.1), delay),
send(B1, clear),
send(B1, display, bitmap('glass_while_animating_2.gif')),
% etc