## Copyright (C) 1994-2012 John W. Eaton
##
## This file is part of Octave.
##
## Octave 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.
##
## Octave 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 Octave; see the file COPYING.  If not, see
## <http://www.gnu.org/licenses/>.

## -*- texinfo -*-
## @deftypefn  {Function File} {} imagesc (@var{img})
## @deftypefnx {Function File} {} imagesc (@var{x}, @var{y}, @var{img})
## @deftypefnx {Function File} {} imagesc (@dots{}, @var{climits})
## @deftypefnx {Function File} {} imagesc (@var{h}, @dots{})
## @deftypefnx {Function File} {@var{h} =} imagesc (@dots{})
## Display a scaled version of the matrix @var{img} as a color image.  The
## colormap is scaled so that the entries of the matrix occupy the entire
## colormap.  If @code{@var{climits} = [@var{lo}, @var{hi}]} is given, then that
## range is set to the "clim" of the current axes.
##
## The axis values corresponding to the matrix elements are specified in
## @var{x} and @var{y}, either as pairs giving the minimum and maximum
## values for the respective axes, or as values for each row and column
## of the matrix @var{img}.
##
## The optional return value @var{h} is a graphics handle to the image.
## @seealso{image, imshow, caxis}
## @end deftypefn

## Author: Tony Richardson <arichard@stark.cc.oh.us>
## Created: July 1994
## Adapted-By: jwe

function h = imagesc (varargin)

  if (nargin < 1 || nargin > 4)
    print_usage ();
  elseif (isscalar (varargin{1}) && ishandle (varargin{1}))
    harg = varargin{1};
    if (! strcmp (get (harg, "type"), "axes"))
      error ("imagesc: expecting first argument to be an axes object");
    endif
    oldh = gca ();
    unwind_protect
      axes (h);
      htmp = __imagesc__ (harg, varargin{2:end});
    unwind_protect_cleanup
      axes (oldh);
    end_unwind_protect
  else
    htmp = __imagesc__ (gca (), varargin{:});
  endif

  if (nargout > 0)
    h = htmp;
  endif

endfunction

function h = __imagesc__ (ax, x, y, img, climits)

  if (nargin == 2)
    img = x;
    x = y = climits = [];
  elseif (nargin == 3)
    img = x;
    climits = y;
    x = y = [];
  elseif (nargin == 4 && ! isscalar (x) && ! isscalar (y) && ! isscalar (img))
    climits = [];
  endif

  h = image (ax, x, y, img);
  set (h, "cdatamapping", "scaled");

  ## use given climits or guess them from the matrix
  if (numel (climits) == 2 && climits(1) <= climits(2))
    set (ax, "clim", climits);
  elseif (! isempty (climits))
    error ("imagesc: CLIMITS must be in form [lo, hi]");
  endif

endfunction


%!demo
%! clf;
%! colormap ("default");
%! img = 1 ./ hilb (11);
%! x = y = -5:5;
%! subplot (2,2,1);
%!  h = imagesc (x, y, img);
%!  ylabel ("limits = [-5.5, 5.5]");
%!  title ("imagesc (x, y, img)");
%! subplot (2,2,2);
%!  h = imagesc (-x, y, img);
%!  title ("imagesc (-x, y, img)");
%! subplot (2,2,3);
%!  h = imagesc (x, -y, img);
%!  title ("imagesc (x, -y, img)");
%!  ylabel ("limits = [-5.5, 5.5]");
%! subplot (2,2,4);
%!  h = imagesc (-x, -y, img);
%!  title ("imagesc (-x, -y, img)");

%!demo
%! clf;
%! colormap ("default");
%! g = 0.1:0.1:10;
%! h = g'*g;
%! imagesc (g, g, sin (h));
%! hold on;
%! imagesc (g, g+12, cos (h/2));
%! axis ([0 10 0 22]);
%! hold off;
%! title ("two consecutive images");

%!demo
%! clf;
%! colormap ("default");
%! g = 0.1:0.1:10;
%! h = g'*g;
%! imagesc (g, g, sin (h));
%! hold all;
%! plot (g, 11.0 * ones (size (g)));
%! imagesc (g, g+12, cos (h/2));
%! axis ([0 10 0 22]);
%! hold off;
%! title ("image, line, image");

%!demo
%! clf;
%! colormap ("default");
%! g = 0.1:0.1:10;
%! h = g'*g;
%! plot (g, 10.5 * ones (size (g)));
%! hold all;
%! imagesc (g, g, sin (h));
%! plot (g, 11.0 * ones (size (g)));
%! imagesc (g, g+12, cos (h/2));
%! plot (g, 11.5 * ones (size (g)));
%! axis ([0 10 0 22]);
%! hold off;
%! title ("line, image, line, image, line");