%%
%% %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.
%% ------------------------------------------------------------
