########################################################################
##
## Copyright (C) 2021-2025 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.
##
## 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.
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## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
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## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING.  If not, see
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########################################################################

## -*- texinfo -*-
## @deftypefn {} {} __check_rendering_capability__ (@var{who}, @var{fig})
## Undocumented internal function.
## @end deftypefn

function __check_rendering_capability__ (who, fig)

  if (strcmp (get (fig, "visible"), "on"))
    return;
  endif

  toolkit = get (fig, "__graphics_toolkit__");

  if (strcmp (toolkit, "qt"))
    return;
  endif

  error ("%s: rendering with %s toolkit requires visible figure (DISPLAY='%s')",
         who, toolkit, getenv ("DISPLAY"));

endfunction
