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−## Copyright (C) 2011-2013 Carnë Draug <carandraug+dev@gmail.com>
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−##
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−## This program is free software; you can redistribute it and/or modify it under
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−## the terms of the GNU General Public License as published by the Free Software
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−## Foundation; either version 3 of the License, or (at your option) any later
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−## version.
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−##
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−## This program is distributed in the hope that it will be useful, but WITHOUT
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−## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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−## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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−## details.
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−##
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−## You should have received a copy of the GNU General Public License along with
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−## this program; if not, see <http://www.gnu.org/licenses/>.
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−
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−## -*- texinfo -*-
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−## @deftypefn {Function File} {@var{range} =} getrangefromclass (@var{img})
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−## Return display range of image.
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−##
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−## For a given image @var{img}, returns the 1x2 element matrix @var{range}
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−## with the display range (minimum and maximum display values) for an
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−## image of that class.
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−##
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−## Images of different classes have different display ranges, the ranges
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−## of values that Octave will interpret between black to white.  For an
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−## integer image, the range is from @code{intmin} to @code{intmax} of
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−## that class; for images of class logical, single, or double, the range
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−## is [0 1].
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−##
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−## Note that @var{range} will be of class double, independently of the class
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−## of @var{img}.
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−##
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−## @example
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−## @group
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−## getrangefromclass (ones (5)) # note that class is 'double'
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−##      @result{} [0   1]
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−## getrangefromclass (logical (ones (5)))
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−##      @result{} [0   1]
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−## getrangefromclass (int8 (ones (5)))
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−##      @result{} [-128  127]
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−## @end group
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−## @end example
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−##
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−## @seealso{intmin, intmax, bitmax}
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−## @end deftypefn
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−
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−function r = getrangefromclass (img)
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−
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−  if (nargin != 1)
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−    print_usage ();
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−  elseif (! isimage (img))
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−    error ("getrangefromclass: IMG must be an image");
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−  endif
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−
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−  cl = class (img);
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−  if (isinteger (img))
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−    r = [intmin(cl) intmax(cl)];
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−  elseif (any (strcmp (cl, {"single", "double", "logical"})))
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−    r = [0 1];
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−  else
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−    error ("getrangefromclass: unrecognized image class `%s'", cl)
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−  endif
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−  r = double (r);
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−endfunction
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−
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−%!shared img
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−%! img = ones (5);
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−%!assert (getrangefromclass (double (img)), [0 1]);      # double returns [0 1]
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−%!assert (getrangefromclass (single (img)), [0 1]);      # single returns [0 1]
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−%!assert (getrangefromclass (logical (img)), [0 1]);     # logical returns [0 1]
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−%!assert (getrangefromclass (int8 (img)), [-128 127]);   # checks int
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−%!assert (getrangefromclass (uint8 (img)), [0 255]);     # checks unit
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−%!fail ("getrangefromclass ('string')");                 # fails with strings
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−%!fail ("getrangefromclass ({3, 4})");                   # fails with cells