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## Copyright (C) 1996-2026 The Octave Project Developers
##
## See the file COPYRIGHT.md in the top-level directory of this
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## along with Octave; see the file COPYING.  If not, see
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########################################################################

## -*- texinfo -*-
## @deftypefn  {} {} plot3 (@var{x}, @var{y}, @var{z})
## @deftypefnx {} {} plot3 (@var{x}, @var{y}, @var{z}, @var{prop}, @var{value}, @dots{})
## @deftypefnx {} {} plot3 (@var{x}, @var{y}, @var{z}, @var{fmt})
## @deftypefnx {} {} plot3 (@var{x}, @var{cplx})
## @deftypefnx {} {} plot3 (@var{cplx})
## @deftypefnx {} {} plot3 (@var{hax}, @dots{})
## @deftypefnx {} {@var{h} =} plot3 (@dots{})
## Produce 3-D 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 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{cplx})
## @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{cplx})
## @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
##
## Multiple property-value pairs may be specified which will affect the line
## objects drawn by @code{plot3}.  If the @var{fmt} argument is supplied it will
## format the line objects in the same manner as @code{plot}.  The full list of
## properties is documented at @ref{Line Properties}.
##
## If the first argument @var{hax} is an axes handle, then plot into this axes,
## rather than the current axes returned by @code{gca}.
##
## The optional return value @var{h} is a graphics handle to the created plot.
##
## Example:
##
## @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{ezplot3, plot}
## @end deftypefn

function h = plot3 (varargin)

  [hax, varargin, nargs] = __plt_get_axis_arg__ ("plot3", varargin{:});

  if (nargs < 1)
    print_usage ();
  endif

  hax = newplot (hax);

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

  ## Gather arguments, decode format, and plot lines.
  arg = 0;
  while (arg++ < nargs)
    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
            y = real (x);
            z = imag (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 < nargs && ischar (varargin{arg+1}))
            if (nargs - 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");
      elseif (ndims (x) > 2)
        error ("plot3: X, Y, and Z must not have more than two dimensions");
      endif

      for i = 1 : columns (x)
        linestyle = options.linestyle;
        marker = options.marker;
        if (isempty (marker) && isempty (linestyle))
          if (isscalar (x))
            ## If unspecified, marker for a point is always "."
            linestyle = "-";
            marker = ".";
          else
            [linestyle, marker] = __next_line_style__ (hax);
          endif
        endif
        color = options.color;
        if (isempty (color))
          color = __next_line_color__ (hax);
        endif

        htmp(++idx) = __go_line__ (hax, "xdata", x(:, i), "ydata", y(:, i),
                                   "zdata", z(:, i),
                                   "color", color, "linestyle", linestyle,
                                   "marker", marker, properties{:});
        key = options.key;
        if (! isempty (key))
          hlgnd = [hlgnd, htmp(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");
      elseif (ndims (x) > 2)
        error ("plot3: X, Y, and Z must not have more than two dimensions");
      endif

      options = __default_plot_options__ ();
      for i = 1 : columns (x)
        linestyle = options.linestyle;
        marker = options.marker;
        if (isempty (marker) && isempty (linestyle))
          if (isscalar (x))
            ## If unspecified, marker for a point is always "."
            linestyle = "-";
            marker = ".";
          else
            [linestyle, marker] = __next_line_style__ (hax);
          endif
        endif
        color = options.color;
        if (isempty (color))
          color = __next_line_color__ (hax);
        endif

        htmp(++idx) = __go_line__ (hax, "xdata", x(:, i), "ydata", y(:, i),
                                   "zdata", z(:, i),
                                   "color", color, "linestyle", linestyle,
                                   "marker", marker, properties{:});
        key = options.key;
        if (! isempty (key))
          hlgnd = [hlgnd, htmp(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
      y = real (x);
      z = imag (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");
    elseif (ndims (x) > 2)
      error ("plot3: X, Y, and Z must not have more than two dimensions");
    endif

    options = __default_plot_options__ ();

    for i = 1 : columns (x)
      linestyle = options.linestyle;
      marker = options.marker;
      if (isempty (marker) && isempty (linestyle))
        if (isscalar (x))
          ## If unspecified, marker for a point is always "."
          linestyle = "-";
          marker = ".";
        else
          [linestyle, marker] = __next_line_style__ (hax);
        endif
      endif
      color = options.color;
      if (isempty (color))
        color = __next_line_color__ (hax);
      endif

      htmp(++idx) = __go_line__ (hax, "xdata", x(:, i), "ydata", y(:, i),
                                 "zdata", z(:, i),
                                 "color", color, "linestyle", linestyle,
                                 "marker", marker, properties{:});
      key = options.key;
      if (! isempty (key))
        hlgnd = [hlgnd, htmp(idx)];
        tlgnd = {tlgnd{:}, key};
      endif
    endfor
  endif

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

  if (! ishold (hax))
    set (hax, "view", [-37.5, 30]);
  endif

  if (nargout > 0)
    h = htmp;
  endif

endfunction


%!demo
%! clf;
%! z = [0:0.05:5];
%! plot3 (cos (2*pi*z), sin (2*pi*z), z);
%! legend ("helix");
%! title ("plot3() of a helix");

%!demo
%! clf;
%! z = [0:0.05:5];
%! plot3 (z, exp (2i*pi*z));
%! legend ("complex sinusoid");
%! title ("plot3() with complex input");
