%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2016. 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%
%%
%%
%% ------------------------------------------------------------
%% Another simple demo for choosing
%% colors in a window.
%% ------------------------------------------------------------
-module(color_demo2).
-compile([{nowarn_deprecated_function,{gs,config,2}},
{nowarn_deprecated_function,{gs,create,3}},
{nowarn_deprecated_function,{gs,create,4}},
{nowarn_deprecated_function,{gs,start,0}}]).
-export([start/0,init/0]).
start() ->
spawn(color_demo2,init,[]).
init() ->
S=gs:start(),
Win = gs:create(window,S,[{width,380},{height,430},{motion,true},
{buttonpress,true}]),
gs:create(button,b1,Win,[{x,200},{label,{text,""}}]),
gs:create(button,Win,[{data,quit},{label,{text,"Quit"}},{bg,yellow},
{width,40}]),
Side = 200,
Tri = equi_tri(100, 400, Side),
%% draw_lines(Win, Tri),
gs:config(Win,[{title,"Color Demo 2"},{map,true}]),
server(Win, Side, Tri, {0,0,0}).
server(Win, Side, [Point1, Point2, Point3], OldCol) ->
receive
{gs,Win,motion,_,[X,Y|_]} ->
R = col({X,Y}, Point1, Side),
G = col({X,Y}, Point2, Side),
B = col({X,Y}, Point3, Side),
Txt = lists:flatten(io_lib:format("~w ~w ~w",[R,G,B])),
gs:config(b1,[{label,{text,Txt}}]),
Col = {R, G, B},
gs:config(Win, [{bg,Col}]),
server(Win, Side, [Point1, Point2, Point3], Col);
{gs,Win,buttonpress,_,[_X,_Y|_]} ->
io:format("{color, ~w}\n", [OldCol]),
server(Win, Side, [Point1, Point2, Point3], OldCol);
{gs,_,click,quit,_} ->
exit(die);
{gs,Win,destroy,_,_} ->
exit(die);
_Any ->
server(Win, Side, [Point1, Point2, Point3], OldCol)
end.
col(Point1, Point2, Side) ->
D = dist(Point1, Point2),
%% All FFFFFF is white
%% when Col = 255 when D = Side
%% when Col = 0 when D = 0
%% Assume Col = A * D + B
B = 0,
A = (255 - B)/Side,
Col = trunc(A*D + B),
map(Col).
map(X) ->
X band 255.
equi_tri(X1, Y1, L) ->
X2 = trunc(X1 + L/2),
Y2 = trunc(Y1 - L * math:sqrt(3)),
[{X1,Y1},{X2,Y2},{X1+L,Y1}].
%draw_line(Win, {X1, Y1}, {X2, Y2}) ->
% gs:create(line,Win,[{coords,[{X1,Y1},{X2,Y2}]},{width,2}]).
%draw_lines(Win, L) ->
% draw1(Win, L),
% draw_line(Win, hd(L), lists:last(L)).
%draw1(Win, [X,Y|T]) ->
% draw_line(Win, X, Y),
% draw1(Win, [Y|T]);
%draw1(Win, _) ->
% [].
dist({X1,Y1},{X2,Y2}) ->
XX = X1 - X2,
YY = Y1 - Y2,
math:sqrt(XX*XX+YY*YY).
%% ------------------------------------------------------------
%% end of color_demo2.erl
