## Copyright (C) 2009 Ben Abbott
##
## 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/>.

## -*- texinfo -*-
## @deftypefn {Function File} {} __actual_axis_position__ (@var{h})
## @deftypefnx {Function File} {} __actual_axis_position__ (@var{axis_struct})
## Undocumented internal function.
## @end deftypefn

## Author: Ben Abbott

function pos = __actual_axis_position__ (axis_obj)
  if (ishandle (axis_obj))
    axis_obj = get (axis_obj);
  endif

  ## When using {rltb}margin, Gnuplot does not handle the specified
  ## aspect ratio properly, so handle it here.
  if (__calc_dimensions__ (axis_obj) == 3)
    ## FIXME -- this works for "axis square", but has not been
    ##          thoroughly tested for other aspect ratios.
    aspect_ratio_2d = [max(axis_obj.dataaspectratio(1:2)), ...
			   axis_obj.dataaspectratio(3)/sqrt(2)];
  else
    aspect_ratio_2d = axis_obj.dataaspectratio(1:2);
  endif
  orig_fig_units = get (axis_obj.parent, "units");
  orig_fig_position = get (axis_obj.parent, "units");
  unwind_protect
    set (axis_obj.parent, "units", "pixels")
    fig_position = get (axis_obj.parent, "position");
    pos_in_pixels = axis_obj.position .* fig_position([3, 4, 3, 4]);
    orig_aspect_ratio_2d = pos_in_pixels(3:4);
    rel_aspect_ratio_2d =  aspect_ratio_2d ./ orig_aspect_ratio_2d;
    rel_aspect_ratio_2d = rel_aspect_ratio_2d ./ max (rel_aspect_ratio_2d);
    if (rel_aspect_ratio_2d(1) < rel_aspect_ratio_2d(2));
      dx = (1.0 - rel_aspect_ratio_2d(1)) * pos_in_pixels(3);
      pos_in_pixels = pos_in_pixels + dx*[0.5, 0.0, -1.0, 0.0];
    elseif (rel_aspect_ratio_2d(1) > rel_aspect_ratio_2d(2))
      dy = (1.0 - rel_aspect_ratio_2d(2)) * pos_in_pixels(4);
      pos_in_pixels = pos_in_pixels + dy*[0.0, 0.5, 0.0, -1.0];
    endif
    pos = pos_in_pixels ./ fig_position([3, 4, 3, 4]);
  unwind_protect_cleanup
    set (axis_obj.parent, "units", orig_fig_units)
    set (axis_obj.parent, "units", orig_fig_position)
  end_unwind_protect

endfunction

function nd = __calc_dimensions__ (obj)
  kids = obj.children;
  nd = 2;
  for i = 1:length (kids)
    obj = get (kids(i));
    switch (obj.type)
      case {"image", "text"}
        ## ignore as they 
      case {"line", "patch"}
        if (! isempty (obj.zdata))
          nd = 3;
        endif
      case "surface"
        nd = 3;
      case "hggroup"
        obj_nd = __calc_dimensions__ (obj);
        if (obj_nd == 3)
          nd = 3;
        endif
    endswitch
  endfor
endfunction