Merge commit 'v3.3.0' into upstream

[debian/gnuradio] / gnuradio-core / src / utils / cool.m

diff --git a/gnuradio-core/src/utils/cool.m b/gnuradio-core/src/utils/cool.m
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+%% Copyright (C) 1999,2000  Kai Habel
+%%
+%% This program is free software; 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
+%% MERCHANTABILITY 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; if not, write to the Free Software
+%% Foundation, Inc., 51 Franklin Street, Boston, MA  02110-1301  USA
+
+%% -*- texinfo -*-
+%% @deftypefn {Function File} {} cool (@var{n})
+%% Create color colormap. 
+%% (cyan to magenta)
+%% The argument @var{n} should be a scalar.  If it
+%% is omitted, the length of the current colormap or 64 is assumed.
+%% @end deftypefn
+%% @seealso{colormap}
+
+%% Author:  Kai Habel <kai.habel@gmx.de>
+
+function map = cool (number)
+
+  if (nargin == 0)
+    number = rows (colormap);
+  elseif (nargin == 1)
+    if (! is_scalar (number))
+      error ("cool: argument must be a scalar");
+    end
+  else
+    usage ("cool (number)");
+  end
+
+  if (number == 1)
+    map = [0, 1, 1];  
+  elseif (number > 1)
+    r = (0:number - 1)' ./ (number - 1);
+    g = 1 - r;
+    b = ones (number, 1);
+    map = [r, g, b];
+  else
+    map = [];
+  end
+