########################################################################
##
## Copyright (C) 2008-2021 The Octave Project Developers
##
## See the file COPYRIGHT.md in the top-level directory of this
## distribution or <https://octave.org/copyright/>.
##
## This file is part of Octave.
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## Octave is free software: you can redistribute it and/or modify it
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########################################################################

## -*- texinfo -*-
## @deftypefn {} {@var{h} =} allchild (@var{handles})
## Find all children, including hidden children, of a graphics object.
##
## This function is similar to @code{get (h, "children")}, but also returns
## hidden objects (HandleVisibility = @qcode{"off"}).
##
## If @var{handles} is a scalar, @var{h} will be a vector.  Otherwise,
## @var{h} will be a cell matrix of the same size as @var{handles} and each
## cell will contain a vector of handles.
## @seealso{findall, findobj, get, set}
## @end deftypefn

function h = allchild (handles)

  if (nargin != 1)
    print_usage ();
  endif

  shh = get (0, "showhiddenhandles");
  unwind_protect
    set (0, "showhiddenhandles", "on");
    h = get (handles, "children");
  unwind_protect_cleanup
    set (0, "showhiddenhandles", shh);
  end_unwind_protect

endfunction


%!testif HAVE_OPENGL, HAVE_QT; have_window_system () && any (strcmp ("qt", available_graphics_toolkits ()))
%! toolkit = graphics_toolkit ("qt");
%! hf = figure ("visible", "off");
%! unwind_protect
%!   l = line;
%!   kids = allchild (hf);
%!   assert (get (kids, "type"), ...
%!           {"axes"; "uitoolbar"; "uimenu"; "uimenu"; "uimenu"});
%! unwind_protect_cleanup
%!   close (hf);
%!   graphics_toolkit (toolkit);
%! end_unwind_protect

%!error allchild ()
%!error allchild (1, 2)