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authorErlang/OTP <[email protected]>2009-11-20 14:54:40 +0000
committerErlang/OTP <[email protected]>2009-11-20 14:54:40 +0000
commit84adefa331c4159d432d22840663c38f155cd4c1 (patch)
treebff9a9c66adda4df2106dfd0e5c053ab182a12bd /lib/gs/examples/ball.erl
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The R13B03 release.OTP_R13B03
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diff --git a/lib/gs/examples/ball.erl b/lib/gs/examples/ball.erl
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+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 1996-2009. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+%%
+%% ------------------------------------------------------------
+%% A simple demo showing a ball
+%% bouncing in a window.
+%% ------------------------------------------------------------
+
+-module(ball).
+
+-export([start/0,init/0]).
+
+start() ->
+ spawn(ball,init,[]).
+
+init() ->
+ I= gs:start(),
+ W= gs:window(I,[{title,"Ball"},{width,300},{height,300},{map,true}]),
+ C= gs:canvas(W,[{width,300},{height,300},{bg,yellow}]),
+ gs:button(W,[{label, {text,"Quit Demo"}},{x,100}]),
+ Ball = gs:oval(C,[{coords,[{0,0},{50,50}]},{fill,red}]),
+ ball(Ball,0,0,5.5,4.1).
+
+ball(Ball,X,Y,DX,DY) ->
+ {NX,NDX} = cc(X,DX),
+ {NY,NDY} = cc(Y,DY),
+ gs:config(Ball,{move,{DX,DY}}),
+ receive
+ {gs,_,click,_,_} -> exit(normal);
+ {gs,_,destroy,_,_} -> exit(normal)
+ after 20 ->
+ true
+ end,
+ ball(Ball,NX,NY,NDX,NDY).
+
+cc(X,DX) ->
+ if
+ DX>0 ->
+ if
+ X=<250 ->
+ {X+DX,DX};
+ x>250 ->
+ {X-DX,-DX}
+ end;
+ DX<0 ->
+ if
+ X>=0 ->
+ {X+DX,DX};
+ X<0 ->
+ {X-DX,-DX}
+ end
+ end.
+
+%% ------------------------------------------------------------