Mercurial > octave
view scripts/image/private/imageIO.m @ 22323:bac0d6f07a3e
maint: Update copyright notices for 2016.
author | John W. Eaton <jwe@octave.org> |
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date | Wed, 17 Aug 2016 01:05:19 -0400 |
parents | b571fc85953f |
children | 3a2b891d0b33 e9a0469dedd9 |
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## Copyright (C) 2013-2016 Carnë Draug ## ## 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 the image input functions imread() and imfinfo() to the ## functions that will actually be used, based on their format. See below ## on the details on how it identifies the format, and to what it defaults. ## ## It will change the input arguments that were passed to imread() and ## imfinfo(). It will change the filename to provide the absolute filepath ## for the file, it will extract the possible format name from the rest of ## the input arguments (in case there was one), and will give an error if ## the file can't be found. ## ## Usage: ## ## func - Function name to use on error message. ## core_func - Function handle for the default function to use if we can't ## find the format in imformats. ## fieldname - Name of the field in the struct returned by imformats that ## has the function to use. ## filename - Most likely the first input argument from the function that ## called this. May be missing the file extension which can be ## on varargin. ## varargin - Followed by all the OTHER arguments passed to imread and ## imfinfo. function varargout = imageIO (func, core_func, fieldname, filename, varargin) ## First thing: figure out the filename and possibly download it. ## The first attempt is to try the filename and see if it exists. If it ## does not, we try to add the next argument since the file extension can ## be given as a separate argument. If we still can't find the file, it ## can be a URL. Lastly, if we still didn't found a file, try adding the ## extension to the URL file_2_delete = false; # will we have to remove the file in the end? persistent abs_path = @(x) file_in_path (IMAGE_PATH, tilde_expand (x)); ## Filename was given with file extension fn = abs_path (filename); if (isempty (fn) && ! isempty (varargin)) ## Maybe if we add a file extension fn = abs_path ([filename "." varargin{1}]); endif ## Maybe we have an URL if (isempty (fn)) file_2_delete = true; # mark file for deletion [fn, ~] = urlwrite (filename, tempname ()); ## Maybe the URL is missing the file extension if (isempty (fn) && ! isempty (varargin)) [fn, ~] = urlwrite ([filename "." varargin{1}], tempname ()); endif if (isempty (fn)) error ("%s: unable to find file %s", func, filename); endif endif ## unwind_protect block because we may have a file to remove in the end unwind_protect ## When guessing the format to use, we first check if the second ## argument is a format defined in imformats. If so, we remove it ## from the rest of arguments before passing them on. If not, we ## try to guess the format from the file extension. Finally, if ## we still don't know the format, we use the Octave core functions ## which is the same for all formats. foo = []; # the function we will use ## We check if the call to imformats (ext) worked using ## "numfields (fmt) > 0 because when it fails, the returned ## struct is not considered empty. ## try the second input argument if (! isempty (varargin) && ischar (varargin{1})) fmt = imformats (varargin{1}); if (numfields (fmt) > 0) foo = fmt.(fieldname); varargin(1) = []; # remove format name from arguments endif endif ## try extension from filename if (isempty (foo)) [~, ~, ext] = fileparts (fn); if (! isempty (ext)) ## remove dot from extension ext = ext(2:end); endif fmt = imformats (ext); if (numfields (fmt) > 0) foo = fmt.(fieldname); endif endif ## use the core function if (isempty (foo)) foo = core_func; endif [varargout{1:nargout}] = foo (fn, varargin{:}); unwind_protect_cleanup if (file_2_delete) unlink (fn); endif end_unwind_protect endfunction