--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/image/private/__imread__.m	Fri Jul 26 00:47:23 2013 +0100
@@ -0,0 +1,185 @@
+## Copyright (C) 2013 Carnë Draug
+## Copyright (C) 2008-2012 Thomas L. Scofield
+## Copyright (C) 2008 Kristian Rumberg
+## Copyright (C) 2006 Thomas Weber
+## Copyright (C) 2005 Stefan van der Walt
+## Copyright (C) 2002 Andy Adler
+##
+## 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/>.
+
+## This function does all the work of imread. It exists here as private
+## function so that imread can use other functions if imformats is
+## configured to. It is also needed so that imformats can create a
+## function handle for it.
+
+## Author: Carnë Draug <carandraug@octave.org>
+## Author: Thomas L. Scofield <scofield@calvin.edu>
+## Author: Kristian Rumberg <kristianrumberg@gmail.com>
+## Author: Thomas Weber <thomas.weber.mail@gmail.com>
+## Author: Stefan van der Walt <stefan@sun.ac.za>
+## Author: Andy Adler
+
+function varargout = __imread__ (filename, varargin)
+
+  if (nargin < 1)
+    print_usage ("imread");
+  elseif (! ischar (filename))
+    error ("imread: FILENAME must be a string");
+  endif
+
+  ## keep track of the varargin offset we're looking at each moment
+  offset    = 1;
+
+  filename  = tilde_expand (filename);
+  fn        = file_in_path (IMAGE_PATH, filename);
+  if (isempty (fn) && nargin >= offset + 1 && ischar (varargin{offset}))
+    ## if we can't find the file, check if the next input is the file extension
+    filename  = [filename "." varargin{offset}];
+    fn        = file_in_path (IMAGE_PATH, filename);
+    offset++;
+  endif
+  if (isempty (fn))
+    error ("imread: cannot find %s", filename);
+  endif
+
+  ## set default for options
+  options = struct ("index", 1);
+
+  ## Index is the only option that can be defined without the parameter/value
+  ## pair style. When defining it here, the string "all" is invalid though.
+  if (nargin >= offset + 1 && ! ischar (varargin{offset}))
+    if (! is_valid_index_option (options.index))
+      error ("imread: IDX must be a numeric vector");
+    endif
+    options.index = varargin{offset};
+    offset++;
+  endif
+
+  if (rem (numel (varargin) - offset + 1, 2) != 0)
+    error ("imread: no pair for all arguments (even number left)");
+  endif
+
+  for idx = offset:2:(numel (varargin) - offset + 1)
+
+    switch (tolower (varargin{idx}))
+
+      case {"frames", "index"},
+        options.index = varargin{idx+1};
+        if (! (is_valid_index_option (options.index)) &&
+            ! (ischar (options.index) && strcmpi (options.index, "all")))
+          error ("imread: value for %s must be a vector or the string `all'");
+        endif
+
+## FIXME: commented until it's implemented in __magick_read__
+##      case "pixelregion",
+##        options.region = varargin{idx+1};
+##        if (! iscell (options.region) || numel (options.region) != 2)
+##          error ("imread: value for %s must be a 2 element cell array",
+##                 varargin{idx});
+##        endif
+##        for reg_idx = 1:2
+##          if (numel (options.region{reg_idx}) == 3)
+##            ## do nothing
+##          elseif (numel (options.region{reg_idx}) == 2)
+##            options.region{reg_idx}(3) = options.region{reg_idx}(2);
+##            options.region{reg_idx}(2) = 1;
+##          else
+##            error ("imread: range for %s must be a 2 or 3 element vector",
+##                   varargin{idx});
+##          endif
+##          options.region{reg_idx} = floor (options.region{reg_idx}(1)): ...
+##                                    floor (options.region{reg_idx}(2)): ...
+##                                    floor (options.region{reg_idx}(3));
+##        endfor
+
+      case "info",
+        ## We ignore this option. This parameter exists in Matlab to
+        ## speed up the reading of multipage TIFF.  It makes no difference
+        ## for us since we're already quite efficient.
+
+      otherwise
+        error ("imread: invalid PARAMETER `%s'", varargin{idx});
+
+    endswitch
+  endfor
+
+  try
+    [varargout{1:nargout}] = __magick_read__ (fn, options);
+
+  catch
+    ## If we can't read it with Magick, maybe the image is in Octave's
+    ## native image format.  This is from back before Octave had 'imread'
+    ## and 'imwrite'. Then we had the functions 'loadimage' and 'saveimage'.
+    ##
+    ## This "image format" seems to be any file that can be read with
+    ## load() and contains 2 variables.  The variable named "map" is a
+    ## colormap and must exist whether the image is indexed or not. The
+    ## other variable must be named "img" or "X" for a "normal" or
+    ## indexed image.
+    ##
+    ## FIXME: this has been deprecated for the next major release (3.8 or 4.0).
+    ##        If someone wants to revive this as yet another image format, a
+    ##        separate Octave package can be written for it, that register the
+    ##        format through imformats.
+
+    magick_error = lasterr ();
+
+    img_field = false;
+    x_field   = false;
+    map_field = false;
+
+    try
+      vars = load (fn);
+      if (isstruct (vars))
+        img_field = isfield (vars, "img");
+        x_field   = isfield (vars, "X");
+        map_field = isfield (vars, "map");
+      endif
+    catch
+      error ("imread: invalid image file: %s", magick_error);
+    end_try_catch
+
+    if (map_field && (img_field || x_field))
+      varargout{2} = vars.map;
+      if (img_field)
+        varargout{1} = vars.img;
+      else
+        varargout{1} = vars.X;
+      endif
+      persistent warned = false;
+      if (! warned)
+        warning ("Octave's native image format has been deprecated.");
+        warned = true;
+      endif
+    else
+      error ("imread: invalid Octave image file format");
+    endif
+
+  end_try_catch
+
+endfunction
+
+## Tests if the value passed to the Index or Frames is valid. This option
+## can be defined in two places, but only in one place can it also be the
+## string "all"
+function bool = is_valid_index_option (arg)
+  ## is the index option
+  bool = false;
+  if (isvector (arg) && isnumeric (arg) && isreal (arg))
+    bool = true;
+  endif
+endfunction