colorboard

[Jaroslav Hajek-2]

hi all,

the attached function can serve as a replacement for image/imagesc if
graphics is not available.
It can use terminal color support (based on ANSI escape sequences) of
several types to display a colorized chessboard corresponding to the
matrix.
Any idea where to put this function? miscellaneous?
Code enhancement suggestions also welcome.

--
RNDr. Jaroslav Hajek
computing expert & GNU Octave developer
Aeronautical Research and Test Institute (VZLU)
Prague, Czech Republic
url: www.highegg.matfyz.cz

[colorboard.m]

---

## 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; see the file COPYING.  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

---

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[Søren Hauberg]

fre, 09 10 2009 kl. 12:37 +0200, skrev Jaroslav Hajek:
> the attached function can serve as a replacement for image/imagesc if
> graphics is not available.
> It can use terminal color support (based on ANSI escape sequences) of
> several types to display a colorized chessboard corresponding to the
> matrix.
> Any idea where to put this function? miscellaneous?
> Code enhancement suggestions also welcome.

Cool. This can easily become useful when accessing machines via ssh. I
guess the 'miscellaneous' seems like the right place.

This makes me think that perhaps Octave should allow you to show figures
using the 'dumb' terminal for gnuplot. This terminal provides ascii
output, which could be useful on slow networks.

Søren


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[Petr Mikulik]

> This makes me think that perhaps Octave should allow you to show figures
> using the 'dumb' terminal for gnuplot. This terminal provides ascii
> output, which could be useful on slow networks.

I have tried (on Linux)
        setenv('GNUTERM', 'dumb');
        plot(1:100)

but it does not produce any output. Isn't the standard output redirected to
/dev/null?

---
PM


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is the only developer event you need to attend this year. Jumpstart your
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