## Copyright (C) 1996, 1997 John W. Eaton
##
## 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 2, 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, write to the Free
## Software Foundation, 59 Temple Place - Suite 330, Boston, MA
## 02111-1307, USA.

## -*- texinfo -*-
## @deftypefn {Function File} {} axis (@var{limits})
## Sets the axis limits for plots.
##
## The argument @var{limits} should be a 2, 4, or 6 element vector.  The
## first and second elements specify the lower and upper limits for the x
## axis.  The third and fourth specify the limits for the y axis, and the
## fifth and sixth specify the limits for the z axis.
##
## With no arguments, @code{axis} turns autoscaling on.
##
## If your plot is already drawn, then you need to use @code{replot} before
## the new axis limits will take effect.  You can get this to happen
## automatically by setting the built-in variable @code{automatic_replot}
## to a nonzero value.
## @end deftypefn

## Author: jwe

function curr_axis = axis (ax)

  ## This may not be correct if someone has used the gnuplot interface
  ## directly...

  global __current_axis__ = [-10, 10, -10, 10];

  if (nargin > 1)
    usage ("axis ([xmin, xmax, ymin, ymax, zmin, zmax])");
  endif

  if (nargin == 0)
    gset autoscale;
    curr_axis = __current_axis__;
  elseif (is_vector (ax))

    len = length (ax);

    if (len != 2 && len != 4 && len != 6)
      error ("axis: expecting vector with 2, 4, or 6 elements");
    endif

    __current_axis__ = reshape (ax, 1, len);

    if (len > 1)
      eval (sprintf ("gset xrange [%g:%g];", ax (1), ax (2)));
    endif

    if (len > 3)
      eval (sprintf ("gset yrange [%g:%g];", ax (3), ax (4)));
    endif

    if (len > 5)
      eval (sprintf ("gset zrange [%g:%g];", ax (5), ax (6)));
    endif

  else
    error ("axis: expecting no args, or a vector with 2, 4, or 6 elements");
  endif

endfunction