## Copyright (C) 1996-2012 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 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} {} plot3 (@var{args})
## Produce three-dimensional plots.  Many different combinations of
## arguments are possible.  The simplest form is
##
## @example
## plot3 (@var{x}, @var{y}, @var{z})
## @end example
##
## @noindent
## in which the arguments are taken to be the vertices of the points to
## be plotted in three dimensions.  If all arguments are vectors of the
## same length, then a single continuous line is drawn.  If all arguments
## are matrices, then each column of the matrices is treated as a
## separate line.  No attempt is made to transpose the arguments to make
## the number of rows match.
##
## If only two arguments are given, as
##
## @example
## plot3 (@var{x}, @var{c})
## @end example
##
## @noindent
## the real and imaginary parts of the second argument are used
## as the @var{y} and @var{z} coordinates, respectively.
##
## If only one argument is given, as
##
## @example
## plot3 (@var{c})
## @end example
##
## @noindent
## the real and imaginary parts of the argument are used as the @var{y}
## and @var{z} values, and they are plotted versus their index.
##
## Arguments may also be given in groups of three as
##
## @example
## plot3 (@var{x1}, @var{y1}, @var{z1}, @var{x2}, @var{y2}, @var{z2}, @dots{})
## @end example
##
## @noindent
## in which each set of three arguments is treated as a separate line or
## set of lines in three dimensions.
##
## To plot multiple one- or two-argument groups, separate each group
## with an empty format string, as
##
## @example
## plot3 (@var{x1}, @var{c1}, "", @var{c2}, "", @dots{})
## @end example
##
## An example of the use of @code{plot3} is
##
## @example
## @group
##    z = [0:0.05:5];
##    plot3 (cos(2*pi*z), sin(2*pi*z), z, ";helix;");
##    plot3 (z, exp(2i*pi*z), ";complex sinusoid;");
## @end group
## @end example
## @seealso{plot, xlabel, ylabel, zlabel, title, print}
## @end deftypefn

## Author: Paul Kienzle
##         (modified from __plt__.m)

function retval = plot3 (varargin)

  newplot ();

  x_set = 0;
  y_set = 0;
  z_set = 0;
  property_set = 0;
  fmt_set = 0;
  properties = {};
  tlgnd = {};
  hlgnd = [];
  idx = 0;

  ## Gather arguments, decode format, and plot lines.
  arg = 0;
  while (arg++ < nargin)
    new = varargin{arg};
    new_cell = varargin(arg);

    if (property_set)
      properties = [properties, new_cell];
      property_set = 0;
      continue;
    endif

    if (ischar (new))
      if (! z_set)
        if (! y_set)
          if (! x_set)
            error ("plot3: needs x, [ y, [ z ] ]");
          else
            z = imag (x);
            y = real (x);
            y_set = 1;
            z_set = 1;
            if (rows(x) > 1)
              x = repmat ((1:rows(x))', 1, columns(x));
            else
              x = 1:columns(x);
            endif
          endif
        else
          z = imag (y);
          y = real (y);
          z_set = 1;
        endif
      endif

      if (! fmt_set)
        [options, valid] = __pltopt__ ("plot3", new, false);
        if (! valid)
          properties = [properties, new_cell];
          property_set = 1;
          continue;
        else
          fmt_set = 1;
          while (arg < nargin && ischar (varargin{arg+1}))
            if (nargin - arg < 2)
              error ("plot3: properties must appear followed by a value");
            endif
            properties = [properties, varargin(arg+1:arg+2)];
            arg += 2;
          endwhile
        endif
      else
        properties = [properties, new_cell];
        property_set = 1;
        continue;
      endif

      if (isvector (x) && isvector (y))
        if (isvector (z))
          x = x(:);
          y = y(:);
          z = z(:);
        elseif (length (x) == rows (z) && length (y) == columns (z))
          [x, y] = meshgrid (x, y);
        else
          error ("plot3: [length(x), length(y)] must match size(z)");
        endif
      endif

      if (! size_equal (x, y, z))
        error ("plot3: x, y, and z must have the same shape");
      endif

      for i = 1 : columns (x)
        linestyle = options.linestyle;
        marker = options.marker;
        if (isempty (marker) && isempty (linestyle))
           [linestyle, marker] = __next_line_style__ ();
        endif
        color = options.color;
        if (isempty (color))
          color = __next_line_color__ ();
        endif

        tmp(++idx) = line (x(:, i), y(:, i), z(:, i),
                           "color", color, "linestyle", linestyle,
                           "marker", marker, properties{:});
        key = options.key;
        if (! isempty (key))
          hlgnd = [hlgnd, tmp(idx)];
          tlgnd = {tlgnd{:}, key};
        endif
      endfor

      x_set = 0;
      y_set = 0;
      z_set = 0;
      fmt_set = 0;
      properties = {};
    elseif (! x_set)
      x = new;
      x_set = 1;
    elseif (! y_set)
      y = new;
      y_set = 1;
    elseif (! z_set)
      z = new;
      z_set = 1;
    else
      if (isvector (x) && isvector (y))
        if (isvector (z))
          x = x(:);
          y = y(:);
          z = z(:);
        elseif (length (x) == rows (z) && length (y) == columns (z))
          [x, y] = meshgrid (x, y);
        else
          error ("plot3: [length(x), length(y)] must match size(z)");
        endif
      endif

      if (! size_equal (x, y, z))
        error ("plot3: x, y, and z must have the same shape");
      endif

      options =  __default_plot_options__ ();
      for i = 1 : columns (x)
        linestyle = options.linestyle;
        marker = options.marker;
        if (isempty (marker) && isempty (linestyle))
           [linestyle, marker] = __next_line_style__ ();
        endif
        color = options.color;
        if (isempty (color))
          color = __next_line_color__ ();
        endif

        tmp(++idx) = line (x(:, i), y(:, i), z(:, i),
                           "color", color, "linestyle", linestyle,
                           "marker", marker, properties{:});
        key = options.key;
        if (! isempty (key))
          hlgnd = [hlgnd, tmp(idx)];
          tlgnd = {tlgnd{:}, key};
        endif
      endfor

      x = new;
      y_set = 0;
      z_set = 0;
      fmt_set = 0;
      properties = {};
    endif

  endwhile

  if (property_set)
    error ("plot3: properties must appear followed by a value");
  endif

  ## Handle last plot.

  if (x_set)
    if (y_set)
      if (! z_set)
        z = imag (y);
        y = real (y);
        z_set = 1;
      endif
    else
      z = imag (x);
      y = real (x);
      y_set = 1;
      z_set = 1;
      if (rows (x) > 1)
        x = repmat ((1:rows (x))', 1, columns(x));
      else
        x = 1:columns(x);
      endif
    endif

    if (isvector (x) && isvector (y))
      if (isvector (z))
        x = x(:);
        y = y(:);
        z = z(:);
      elseif (length (x) == rows (z) && length (y) == columns (z))
        [x, y] = meshgrid (x, y);
      else
        error ("plot3: [length(x), length(y)] must match size(z)");
      endif
    endif

    if (! size_equal (x, y, z))
      error ("plot3: x, y, and z must have the same shape");
    endif

    options =  __default_plot_options__ ();

    for i = 1 : columns (x)
      linestyle = options.linestyle;
      marker = options.marker;
      if (isempty (marker) && isempty (linestyle))
        [linestyle, marker] = __next_line_style__ ();
      endif
      color = options.color;
      if (isempty (color))
        color = __next_line_color__ ();
      endif

      tmp(++idx) = line (x(:, i), y(:, i), z(:, i),
                         "color", color, "linestyle", linestyle,
                         "marker", marker, properties{:});
      key = options.key;
      if (! isempty (key))
        hlgnd = [hlgnd, tmp(idx)];
        tlgnd = {tlgnd{:}, key};
      endif
    endfor
  endif

  if (!isempty (hlgnd))
    legend (gca(), hlgnd, tlgnd);
  endif

  set (gca (), "view", [-37.5, 30]);

  if (nargout > 0 && idx > 0)
    retval = tmp;
  endif

endfunction

%!demo
%! clf
%! z = [0:0.05:5];
%! plot3 (cos(2*pi*z), sin(2*pi*z), z, ";helix;");
%! plot3 (z, exp(2i*pi*z), ";complex sinusoid;");