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%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2003-2021. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
-module(otp_4790).
-export([?MODULE/0]).
?MODULE() ->
pan_test().
% --------------------------- OTP Ticket --------------------------------
% *Id: OTP-4790
% *Notes: In the code below, the compiler incorrectly assumes
% wings_pref:get_value(pan_speed) returns a float,
% causing a crash at run-time.
% The same error could cause tuple tests to be removed,
% but that would probably only cause a crash if the
% Erlang code was incorrect or if it depended on a catch
% to catch exceptions. Therefore, I consider it unlikely
% that Erlang programs that don't use floating point
% arithmetic are likely to be bitten by this bug.
% -----------------------------------------------------------------------
-record(view, {pan_x,pan_y,distance}).
pan_test() ->
pan(13, 3).
pan(Dx0, Dy0) ->
#view{pan_x=PanX0,pan_y=PanY0,distance=D} = View = current(),
S = D*(1/8)/(51-pref_get_value(pan_speed)),
Dx = Dx0*S,
Dy = Dy0*S,
PanX = PanX0 + Dx,
PanY = PanY0 - Dy,
set_current(View#view{pan_x=PanX,pan_y=PanY}).
current() ->
#view{pan_x=2.0,pan_y=9.75,distance=25.3}.
set_current(#view{pan_x=X,pan_y=Y,distance=D})
when is_float(X), is_float(Y), is_float(D) ->
io:format("X=~p Y=~p D=~p\n", [X,Y,D]).
pref_get_value(pan_speed) ->
32.
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