# Copyright (C) 1998 A. Scottedward Hodel 
#
# 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, 675 Mass Ave, Cambridge, MA 02139, USA. 

function axvec = axis2dlim(axdata)
# function axvec = axis2dlim(axdata)
# determine axis limits for 2-d data; leaves a 10% margin around the plots.
# puts in margins of +/- 0.1 if data is one dimensional (or a single point)
# inputs:
#   axdata: nx2 matrix of data [x,y]
# outputs:
#   vector of axis limits appropriate for call to axis() function
 
  if(isempty(axdata))
    axdata = 0;
  endif

  # compute axis limits
  minv = min(axdata);
  maxv = max(axdata);
  delv = (maxv-minv)/2;      # breadth of the plot
  midv = (minv + maxv)/2;    # midpoint of the plot
  axmid = [midv(1), midv(1), midv(2), midv(2)];
  axdel = [-0.1, 0.1,-0.1,0.1];   # default plot width (if less than 2-d data)
  if(max(delv) == 0)
    if(midv(1) != 0)
      axdel(1:2) = [-0.1*midv(1),0.1*midv(1)];
    endif
    if(midv(2) != 0)
      axdel(3:4) = [-0.1*midv(2),0.1*midv(2)];
    endif
  else
    # they're at least one-dimensional
    if(delv(1) != 0)
      axdel(1:2) = 1.1*[-delv(1),delv(1)];
    endif
    if(delv(2) != 0)
      axdel(3:4) = 1.1*[-delv(2),delv(2)];
    endif
  endif
  axvec = axmid + axdel; 
endfunction

