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scripts/image/gray.m

changeset 10289: 4b124317dc38
parent:a1dbe9d80eee
author: John W. Eaton <jwe@octave.org>
date: Tue Feb 09 20:58:55 2010 -0500 (56 minutes ago)
permissions: -rw-r--r--
description: base_properties::set_children: account for hidden children 
     1## Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2005, 2006, 2007

     2##               John W. Eaton

     3##

     4## This file is part of Octave.

     5##

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

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

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

     9## your option) any later version.

    10##

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

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

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

    14## General Public License for more details.

    15##

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

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

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

    19

    20## -*- texinfo -*-

    21## @deftypefn {Function File} {} gray (@var{n})

    22## Return a gray colormap with @var{n} entries corresponding to values from

    23## 0 to @var{n}-1.  The argument @var{n} should be a scalar.  If it is

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

    25## @end deftypefn

    26

    27## Author: Tony Richardson <arichard@stark.cc.oh.us>

    28## Created: July 1994

    29## Adapted-By: jwe

    30

    31function map = gray (number)

    32

    33  if (nargin == 0)

    34    number = rows (colormap);

    35  elseif (nargin == 1)

    36    if (! isscalar (number))

    37      error ("gray: argument must be a scalar");

    38    endif

    39  else

    40    print_usage ();

    41  endif

    42

    43  gr = [0:(number-1)]';

    44

    45  map = [ gr, gr, gr ] / (number - 1);

    46

    47endfunction

    48

    49%!demo

    50%! ## Show the 'gray' colormap as an image

    51%! image (1:64, linspace (0, 1, 64), repmat (1:64, 64, 1)')

    52%! axis ([1, 64, 0, 1], "ticy", "xy")

    53%! colormap gray

    54