--- /dev/null
+## Copyright (C) 2009 VZLU Prague, a.s.
+##
+## 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, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn{Function File} colorboard (@var{m}, @var{palette}, @var{options})
+## Displays a color board corresponding to a numeric matrix @var{m}.
+## @var{m} should contain zero-based indices of colors.
+## The available range of indices is given by the @var{palette} argument,
+## which can be one of the following:
+##
+## @itemize
+## @item "b&w"
+## Black & white, using reverse video mode. This is the default if @var{m} is logical.
+## @item "ansi8"
+## The standard ANSI 8 color palette. This is the default unless @var{m} is logical.
+## @item "aix16"
+## The AIXTerm extended 16-color palette. Uses codes 100:107 for bright colors.
+## @item "xterm16"
+## The first 16 system colors of the Xterm 256-color palette.
+## @item "xterm216"
+## The 6x6x6 color cube of the Xterm 256-color palette.
+## In this case, matrix can also be passed as a MxNx3 RGB array with values 0..5.
+## @item "grayscale"
+## The 24 grayscale levels of the Xterm 256-color palette.
+## @item "xterm256"
+## The full Xterm 256-color palette. The three above palettes together.
+## @end itemize
+##
+## @var{options} comprises additional options. The recognized options are:
+##
+## @itemize
+## @item "indent"
+## The number of spaces by which the board is indented. Default 2.
+## @item "spaces"
+## The number of spaces forming one field. Default 2.
+## @item "horizontalseparator"
+## The character used for horizontal separation of the table. Default "#".
+## @item "verticalseparator"
+## The character used for vertical separation of the table. Default "|".
+## @end itemize
+## @end deftypefn
+
+function colorboard (m, palette, varargin)
+ if (nargin < 1)
+ print_usage ();
+ endif
+
+ nopt = length (varargin);
+
+ ## default options
+
+ indent = 2;
+ spc = 2;
+ vsep = "|";
+ hsep = "#";
+
+ ## parse options
+
+ while (nopt > 1)
+ switch (tolower (varargin{nopt-1}))
+ case "indent"
+ indent = varargin{nopt};
+ case "spaces"
+ spc = varargin{nopt};
+ case "verticalseparator"
+ vsep = varargin{nopt};
+ case "horizontalseparator"
+ hsep = varargin{nopt};
+ otherwise
+ error ("unknown option: %s", varargin{nopt-1});
+ endswitch
+ nopt -= 2;
+ endwhile
+
+ if (nargin == 1)
+ if (islogical (m))
+ palette = "b&w";
+ else
+ palette = "ansi8";
+ endif
+ endif
+
+ persistent digs = char (48:55); # digits 0..7
+
+ switch (palette)
+ case "b&w"
+ colors = ["07"; "27"];
+ case "ansi8"
+ i = ones (1, 8);
+ colors = (["4"(i, 1), digs.']);
+ case "aix16"
+ i = ones (1, 8);
+ colors = (["04"(i, :), digs.'; "10"(i, :), digs.']);
+ case "xterm16"
+ colors = xterm_palette (0:15);
+ case "xterm216"
+ colors = xterm_palette (16:231);
+ if (size (m, 3) == 3)
+ m = (m(:,:,1)*6 + m(:,:,2))*6 + m(:,:,3);
+ endif
+ case "grayscale"
+ colors = xterm_palette (232:255);
+ case "xterm256"
+ colors = xterm_palette (0:255);
+ otherwise
+ error ("colorboard: invalid palette");
+ endswitch
+
+ nc = rows (colors);
+
+ persistent esc = char (27);
+ escl = [esc, "["](ones (1, nc), :);
+ escr = ["m", blanks(spc)](ones (1, nc), :);
+
+ colors = [escl, colors, escr].';
+
+ [rm, cm] = size (m);
+
+ if (isreal (m) && max (m(:)) <= 1)
+ m = min (floor (nc * m), nc-1);
+ endif
+
+ try
+ board = reshape (colors(:, m + 1), [], rm, cm);
+ catch
+ error ("colorboard: m is not a valid index into palette");
+ end_try_catch
+
+ board = permute (board, [2, 1, 3])(:, :);
+
+ persistent reset = [esc, "[0m"];
+
+ indent = blanks (indent);
+ vline = [indent, hsep(1, ones (1, spc*cm+2))];
+ hlinel = [indent, vsep](ones (1, rm), :);
+ hliner = [reset, vsep](ones (1, rm), :);
+
+ oldpso = page_screen_output (0);
+ unwind_protect
+
+ disp ("");
+ disp (vline);
+ disp ([hlinel, board, hliner]);
+ disp (vline);
+ disp ("");
+
+ puts (reset); # reset terminal
+
+ unwind_protect_cleanup
+ page_screen_output (oldpso);
+ end_unwind_protect
+
+endfunction
+
+function pal = xterm_palette (r)
+ if (max (r) < 100)
+ fmt = "48;5;%02d"; l = 7;
+ else
+ fmt = "48;5;%03d"; l = 8;
+ endif
+ pal = reshape (sprintf (fmt, r), l, length (r)).';
+endfunction