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scripts/image/flag.m

changeset 10289: 4b124317dc38
parent:16f53d29049f
author: John W. Eaton <jwe@octave.org>
date: Tue Feb 09 20:58:55 2010 -0500 (65 minutes ago)
permissions: -rw-r--r--
description: base_properties::set_children: account for hidden children 
     1## Copyright (C) 1999, 2000, 2007, 2009 Kai Habel

     2##

     3## This file is part of Octave.

     4##

     5## Octave is free software; you can redistribute it and/or modify it

     6## under the terms of the GNU General Public License as published by

     7## the Free Software Foundation; either version 3 of the License, or (at

     8## your option) any later version.

     9##

    10## Octave is distributed in the hope that it will be useful, but

    11## WITHOUT ANY WARRANTY; without even the implied warranty of

    12## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    13## General Public License for more details.

    14##

    15## You should have received a copy of the GNU General Public License

    16## along with Octave; see the file COPYING.  If not, see

    17## <http://www.gnu.org/licenses/>.

    18

    19## -*- texinfo -*-

    20## @deftypefn {Function File} {} flag (@var{n})

    21## Create color colormap.  This colormap cycles through red, white, blue 

    22## and black.  The argument @var{n} should be a scalar.  If it

    23## is omitted, the length of the current colormap or 64 is assumed.

    24## @seealso{colormap}

    25## @end deftypefn

    26

    27## Author:  Kai Habel <kai.habel@gmx.de>

    28

    29## flag(number) gives a colormap consists of red, white, blue and black

    30## changing with each index

    31

    32function map = flag (number)

    33

    34  if (nargin == 0)

    35    number = rows (colormap);

    36  elseif (nargin == 1)

    37    if (! isscalar (number))

    38      error ("flag: argument must be a scalar");

    39    endif

    40  else

    41    print_usage ();

    42  endif

    43

    44  p = [1, 0, 0; 1, 1, 1; 0, 0, 1; 0, 0, 0];

    45  if (rem(number,4) == 0)

    46    map = kron (ones (number / 4, 1), p);

    47  else

    48    m1 = kron (ones (fix (number / 4), 1), p);

    49    m2 = p(1:rem (number, 4), :);

    50    map = [m1; m2];

    51  endif

    52

    53endfunction

    54

    55%!demo

    56%! ## Show the 'flag' colormap as an image

    57%! image (1:64, linspace (0, 1, 64), repmat (1:64, 64, 1)')

    58%! axis ([1, 64, 0, 1], "ticy", "xy")

    59%! colormap flag

    60