## Copyright (C) 2007-2017 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  {} {} text (@var{x}, @var{y}, @var{string})
## @deftypefnx {} {} text (@var{x}, @var{y}, @var{z}, @var{string})
## @deftypefnx {} {} text (@dots{}, @var{prop}, @var{val}, @dots{})
## @deftypefnx {} {@var{h} =} text (@dots{})
## Create a text object with text @var{string} at position @var{x}, @var{y},
## (@var{z}) on the current axes.
##
## Multiple locations can be specified if @var{x}, @var{y}, (@var{z}) are
## vectors.  Multiple strings can be specified with a character matrix or
## a cell array of strings.
##
## Optional property/value pairs may be used to control the appearance of the
## text.
##
## The optional return value @var{h} is a vector of graphics handles to the
## created text objects.
## @seealso{gtext, title, xlabel, ylabel, zlabel}
## @end deftypefn

## Author: jwe

## Note: The following code is rigged for Matlab compatibility and is
##       full of hidden assumptions.  Be very wary when modifying.

function h = text (varargin)

  nargs = nargin;
  offset = 0;

  if (nargs > 2 && isnumeric (varargin{1}) && isnumeric (varargin{2}))
    x = varargin{1};
    y = varargin{2};

    if (nargin > 3 && isnumeric (varargin{3}))
      z = varargin{3};
      offset = 4;
    else
      z = zeros (size (x));
      offset = 3;
    endif

    string = varargin{offset};
    varargin(1:offset) = [];

    nx = numel (x);
    ny = numel (y);
    nz = numel (z);
    if (nx != ny || nx != nz)
      error ("text: number of X, Y, and Z coordinates must match");
    endif

    if (ischar (string))

      do_keyword_repl = true;
      nt = rows (string);
      if (nx == 1 && (nt == 1 || nt == 0))
        ## Single text object with one line or empty line
        string = {string};
        nt = 1;
      elseif (nx == 1 && nt > 1)
        ## Single text object with multiple lines
        ## FIXME: "default" or "factory" as first row
        ##        should be escaped to "\default" or "\factory"
        ##        Other rows do not require escaping.
        do_keyword_repl = false;
        string = {string};
      elseif (nx > 1 && nt == nx)
        ## Multiple text objects with different strings
        string = cellstr (string);
      elseif (nx > 1 && nt == 1)
        ## Multiple text objects with same string
        string = repmat ({string}, [nx, 1]);
        nt = nx;
      else
        error ("text: Invalid combination of points and text strings");
      endif

      ## Escape special keywords
      if (do_keyword_repl)
        string = regexprep (string, '^(default|factory)$', '\\$1');
      endif

    elseif (iscell (string))

      nt = numel (string);
      if (nx == 1)
        ## Single text object with one or more lines
        string = {cellstr(string)};
        nt = 1;
      elseif (nx > 1 && nt == nx)
        ## Multiple text objects with different strings
      elseif (nx > 1 && nt == 1)
        ## Multiple text objects with same string
        string = repmat ({cellstr(string)}, [nx, 1]);
        nt = nx;
      else
        error ("text: Invalid combination of points and text strings");
      endif

    else

      error ("text: STRING must be a character string or cell array of character strings");

    endif
  else  # Only PROP/VALUE pairs
    x = y = z = 0;
    nx = ny = nz = 1;
    string = {""};
    nt = 1;
  endif

  ## Any remaining inputs must occur as PROPERTY/VALUE pairs
  if (rem (numel (varargin), 2) != 0)
    print_usage ();
  endif

  ## Get axis argument which may be in a 'parent' PROP/VAL pair
  [hax, varargin] = __plt_get_axis_arg__ ("text", varargin{:});
  if (isempty (hax))
    hax = gca ();
  else
    hax = hax(1);
  endif

  ## Position argument may alse be in PROP/VAL pair
  idx = find (strcmpi (varargin, "position"), 1);
  if (idx)
    pos = varargin{idx+1};
    varargin(idx:idx+1) = [];
  else
    pos = [x(:), y(:), z(:)];
  endif

  ## Call __go_text__ to do the work
  htmp = zeros (nt, 1);
  if (nx == 1)
    htmp = __go_text__ (hax, "string", string{1},
                             ## varargin first, in case "Units" set for pos.
                             varargin{:},
                             "position", pos);
  else
    for n = 1:nt
      htmp(n) = __go_text__ (hax, "string", string{n},
                                  varargin{:},
                                  "position", pos(n,:));
    endfor
    __request_drawnow__ ();
  endif

  if (nargout > 0)
    h = htmp;
  endif

endfunction


%!demo
%! clf;
%! ha = {"left", "center", "right"};
%! va = {"bottom", "middle", "top"};
%! x = [0.25 0.5 0.75];
%! y = x;
%! for t = 0:30:359;
%!   for nh = 1:numel (ha)
%!     for nv = 1:numel (va)
%!       text (x(nh), y(nv), "Hello World", ...
%!             "rotation", t, ...
%!             "horizontalalignment", ha{nh}, ...
%!             "verticalalignment", va{nv});
%!     endfor
%!   endfor
%! endfor
%! set (gca, "xtick", [0.25, 0.5, 0.75], ...
%!           "xticklabel", ha, ...
%!           "ytick", [0.25, 0.5, 0.75], ...
%!           "yticklabel", va);
%! axis ([0 1 0 1]);
%! xlabel ("horizontal alignment");
%! ylabel ("vertical alignment");
%! title ("text alignment and rotation (0:30:360 degrees)");

%!demo
%! clf;
%! h = mesh (peaks, "edgecolor", 0.7 * [1 1 1], ...
%!                  "facecolor", "none", ...
%!                  "facealpha", 0);
%! for t = 0:45:359;
%!   text (25, 25, 0, "Vertical Alignment = Bottom", ...
%!                    "rotation", t, ...
%!                    "horizontalalignment", "left", ...
%!                    "verticalalignment", "bottom");
%! endfor
%! caxis ([-100 100]);
%! title ("Vertically Aligned at Bottom");

%!demo
%! clf;
%! axis ([0 8 0 8]);
%! title (["1st title";"2nd title"]);
%! xlabel (["1st xlabel";"2nd xlabel"]);
%! ylabel (["1st ylabel";"2nd ylabel"]);
%! text (4, 4, {"Hello", "World"}, ...
%!       "horizontalalignment", "center", ...
%!       "verticalalignment", "middle");
%! grid on;

%!demo
%! clf;
%! h = mesh (peaks (), "edgecolor", 0.7 * [1 1 1], ...
%!                     "facecolor", "none", ...
%!                     "facealpha", 0);
%! title (["1st title";"2nd title"]);
%! xlabel (["1st xlabel";"2nd xlabel"]);
%! ylabel (["1st ylabel";"2nd ylabel"]);
%! zlabel (["1st zlabel";"2nd zlabel"]);
%! text (0, 0, 5, {"Hello", "World"}, ...
%!       "horizontalalignment", "center", ...
%!       "verticalalignment", "middle");
%! hold on;
%! plot3 (0, 0, 5, "+k");

%!demo
%! clf;
%! h = text (0.5, 0.3, "char");
%! h = text (0.5, 0.4, ["char row 1"; "char row 2"]);
%! h = text (0.5, 0.6, {"cell2str (1,1)", "cell2str (1,2)"; "cell2str (2,1)", "cell2str (2,2)"});
%! h = text (0.5, 0.8, "foobar");
%! set (h, "string", 1:3);
%! h = text ([0.1, 0.1], [0.3, 0.4], "one string & two objects");
%! h = text ([0.1, 0.1], [0.5, 0.6], {"one cellstr & two objects"});
%! h = text ([0.1, 0.1], [0.7, 0.8], {"cellstr 1 object 1", "cellstr 2 object 2"});
%! h = text ([0.1, 0.1], [0.1, 0.2], ["1st string & 1st object"; "2nd string & 2nd object"]);
%! h = text (0.7, 0.6, "single string");
%! h = text (0.7, 0.5, {"single cell-string"});
%! xlabel (1:2);
%! ylabel (1:2);
%! title (1:2);

%!test
%! hf = figure ("visible", "off");
%! unwind_protect
%!   ## Single object with one line
%!   h = text (0.5, 0.5, "single object with one line");
%!   obs = get (h, "string");
%!   assert (class (obs), "char");
%!   assert (obs, "single object with one line");
%!
%!   ## Single object with multiple lines
%!   h = text (0.5, 0.3, ["char row 1"; "char row 2"]);
%!   obs = get (h, "string");
%!   assert (class (obs), "char");
%!   assert (obs, ["char row 1"; "char row 2"]);
%!
%!   ## Multiple objects with single line
%!   h = text ([0.1, 0.1], [0.3, 0.4], "two objects with same string");
%!   assert (class (get (h(1), "string")), "char");
%!   assert (class (get (h(2), "string")), "char");
%!   assert (get (h(1), "string"), "two objects with same string");
%!   assert (get (h(2), "string"), "two objects with same string");
%!
%!   ## Multiple objects with multiple lines
%!   h = text ([0.7, 0.7], [0.3, 0.4], ["string1"; "string2"]);
%!   assert (class (get (h(1), "string")), "char");
%!   assert (class (get (h(2), "string")), "char");
%!   assert (get (h(1), "string"), "string1");
%!   assert (get (h(2), "string"), "string2");
%!
%!   ## Test special keyword processing
%!   h = text (0.5, 0.5, "default");
%!   assert (get (h, "string"), "default");
%!   h = text (0.5, 0.5, "factory");
%!   assert (get (h, "string"), "factory");
%!
%!   ## Test special null ("") string
%!   h = text (0.5, 0.5, "");
%!   assert (get (h, "string"), "");
%!
%! unwind_protect_cleanup
%!   close (hf);
%! end_unwind_protect

## Tests repeated with cell input ##
%!test
%! hf = figure ("visible", "off");
%! unwind_protect
%!   ## Single object with one line
%!   h = text (0.5, 0.5, {"single object with one line"});
%!   obs = get (h, "string");
%!   assert (class (obs), "cell");
%!   assert (obs, {"single object with one line"});
%!
%!   # Single object with multiple lines
%!   h = text (0.5, 0.3, {"cell2str (1,1)", "cell2str (1,2)";
%!                        "cell2str (2,1)", "cell2str (2,2)"});
%!   obs = get (h, "string");
%!   assert (class (obs), "cell");
%!   assert (obs, {"cell2str (1,1)"; "cell2str (2,1)";
%!                 "cell2str (1,2)"; "cell2str (2,2)"});
%!
%!   ## Single object with multiple lines including empty cell
%!   h = text (0.5, 0.9, {"Line1"; []; "Line3"});
%!   obs = get (h, "string");
%!   assert (class (obs), "cell");
%!   assert (obs, {"Line1"; ""; "Line3"});
%!
%!   ## Multiple objects with single line
%!   h = text ([0.1, 0.1], [0.5, 0.6], {"two objects with same cellstr"});
%!   assert (class (get (h(1), "string")), "cell");
%!   assert (class (get (h(2), "string")), "cell");
%!   assert (get (h(1), "string"), {"two objects with same cellstr"});
%!   assert (get (h(2), "string"), {"two objects with same cellstr"});
%!
%!   ## Multiple objects with multiple lines
%!   h = text ([0.1, 0.1], [0.7, 0.8], {"cellstr1", "cellstr2"});
%!   assert (class (get (h(1), "string")), "char");
%!   assert (class (get (h(2), "string")), "char");
%!   assert (get (h(1), "string"), "cellstr1");
%!   assert (get (h(2), "string"), "cellstr2");
%!
%! unwind_protect_cleanup
%!   close (hf);
%! end_unwind_protect

## Test input validation
%!error <X, Y, and Z coordinates must match> text (1, [2 3], "foobar")
%!error <X, Y, and Z coordinates must match> text (1, 2, [3 4], "foobar")
%!error <Invalid combination> text ([1 2], [3, 4], ['a'; 'b'; 'c'])
%!error <Invalid combination> text ([1 2], [3, 4], {'a', 'b', 'c'})
%!error <STRING must be a character string> text (1, 2, 3)
%!error text ("abc")