From octave-sources-request at bevo dot che dot wisc dot edu  Wed May  9 05:23:43 2001
Subject: bar.m improvements
From: Walery Studennikov <hqsoftware at mail dot ru>
To: octave-sources at bevo dot che dot wisc dot edu
Date: Wed, 9 May 2001 15:27:40 -0400


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Here are my version of bar.m with some improvements:

Now it is possible to specify bars width by the third argument


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## 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 -*-
##  at deftypefn {Function File} {} bar (@var{x}, @var{y})
## Given two vectors of x-y data,  at code{bar} produces a bar graph.
##
## If only one argument is given, it is taken as a vector of y-values
## and the x coordinates are taken to be the indices of the elements.
##
## If two output arguments are specified, the data are generated but
## not plotted.  For example,
##
##  at example
## bar (x, y);
##  at end example
##
##  at noindent
## and
##
##  at example
## [xb, yb] = bar (x, y);
## plot (xb, yb);
##  at end example
##
##  at noindent
## are equivalent.
##  at end deftypefn
##  at seealso{plot, semilogx, semilogy, loglog, polar, mesh, contour,
## stairs, gplot, gsplot, replot, xlabel, ylabel, and title}

## Author: jwe

function [xb, yb] = bar (x, y, wid)
  width = 0.8;

  if (nargin == 1 || is_scalar(y) )

    if nargin == 2
      width = y;
    endif
    space = (1 - width)/2;

    if (is_vector (x))
      len = 4 * length (x) + 2;
      tmp_xb = tmp_yb = zeros (len, 1);
      tmp_xb(1) = 0.5;
      tmp_yb(1) = 0.0;
      k = 0.5;
      for i = 2:4:len-1
        tmp_xb(i) = k + space;
        tmp_xb(i+1) = k + space;
        tmp_xb(i+2) = k + space + width;
        tmp_xb(i+3) = k + space + width;

        tmp_yb(i) = 0.0;
        tmp_yb(i+1) = x(k);
        tmp_yb(i+2) = x(k);
        tmp_yb(i+3) = 0.0;
        k++;
      endfor
      tmp_xb(len) = k;
      tmp_yb(len) = 0.0;
    else
      error ("bar: argument must be a vector");
    endif
  elseif (nargin == 2 || is_scalar(wid))
    if (is_vector (x) && is_vector (y))

      if nargin == 3
        width = wid;
      endif

      xlen = length (x);
      ylen = length (y);
      if (xlen == ylen)
        len = 4 * xlen;
        tmp_xb = tmp_yb = zeros (len, 1);
        cutoff = zeros (1, xlen-1);
        for i = 1:xlen-1
          cutoff(i) = (x(i) + x(i+1)) / 2.0;
        endfor
        delta_p = cutoff(1) - x(1);
        delta_m = delta_p;
        k = 1;
        for i = 1:4:len
          tmp_xb(i+0) = x(k) - delta_m * width;
          tmp_xb(i+1) = tmp_xb(i+0);
          tmp_xb(i+2) = x(k) + delta_p * width;
          tmp_xb(i+3) = tmp_xb(i+2);
          tmp_yb(i+0) = 0.0;
          tmp_yb(i+1) = y(k);
          tmp_yb(i+2) = y(k);
          tmp_yb(i+3) = 0.0;
          if (k < xlen)
            if (x(k+1) < x(k))
              error ("bar: x vector values must be in ascending order");
            endif
            delta_m = x(k+1) - cutoff(k);
            k++;
            if (k < xlen)
              delta_p = cutoff(k) - x(k);
            else
              delta_p = delta_m;
            endif
          endif
        endfor
      else
        error ("bar: arguments must be the same length");
      endif
    else
      error ("bar: arguments must be vectors");
    endif
  else
    usage ("[xb, yb] = bar (x, y)");
  endif

  if (nargout == 0)
    plot (tmp_xb, tmp_yb);
  else
    xb = tmp_xb;
    yb = tmp_yb;
  endif

endfunction

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