Subversion Repositories wbpwmaudio

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%% Filename:    mymap.m

%%

%% Project:     A Wishbone Controlled PWM (audio) controller

%%

%% Purpose:     This file generates my favorite spectrogram color map.  The map

%%              is designed so that zero maps to black, and one maps to white.

%%      In between the two extremes, the color goes from black to blue, red,

%%      orange, yellow, and then white.

%%

%%      The one argument given to the colormap is the number of colors

%%      you would like to have in your map.  64 is often sufficient.

%%

%% Creator:     Dan Gisselquist, Ph.D.

%%              Gisselquist Technology, LLC

%%

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%%

%% Copyright (C) 2017, Gisselquist Technology, LLC

%%

%% This program is free software (firmware): you can redistribute it and/or

%% modify it under the terms of the GNU General Public License as published

%% by the Free Software Foundation, either version 3 of the License, or (at

%% your option) any later version.

%%

%% This program is distributed in the hope that it will be useful, but WITHOUT

%% ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or

%% FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

%% for more details.

%%

%% You should have received a copy of the GNU General Public License along

%% with this program.  (It's in the $(ROOT)/doc directory.  Run make with no

%% target there if the PDF file isn't present.)  If not, see

%% <http://www.gnu.org/licenses/> for a copy.

%%

%% License:     GPL, v3, as defined and found on www.gnu.org,

%%              http://www.gnu.org/licenses/gpl.html

%%

%%

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function [map] = mymap(nclrs)

        map = zeros(nclrs,3);

        idx = ((1:nclrs)-1)/(nclrs-1);

        map(:,1) = 1 - cos((idx-1/3)*3*pi)';

        map((idx<1/3),1) = 0;

        map((idx>2/3),1) = 1;

        map(:,2) = 1 - cos((idx-2/3)*3*pi)';

        map(idx<2/3,2) = 0;

        map(:,3) = 0.5 * (1-cos(idx*3*pi))';

        map((idx<5/6)&(idx>=2/3),3) = 0;

        map((idx>=5/6),3) = 1-cos((idx(idx>=5/6)-2/3)*1.5*pi)';

        map(map>1.0) = 1.0;

        map(map<0.0) = 0.0;