Support TeX elements in FreeType renderer. * libinterp/corefcn/txt-eng.cc: New file. Contains mapping from symbol name to character code, in Unicode and MS symbol. * libinterp/corefcn/modules.mk (COREFCN_SRC): Add txt-eng.cc. * libinterp/corefcn/oct-tex-lexer.ll: Add "\n" to rules applicable to ".", as the latter does not include new line characters. * libinterp/corefcn/oct-tex-parser.yy: Remove debug statements. * libinterp/corefcn/txt-eng.ft.cc (gripe_missing_glyph, gripe_glyph_render): Change signature from char to FT_ULong. (ft_render::ft_render): Adapt to new/removed members. (ft_render::~ft_render): Remove use of fonts member. (ft_render::set_font): Likewise. Use font instead. (ft_render::push_new_line): Likewise. Change meaning of yoffset and initialize line_yoffset. (ft_render::update_line_bbox): New method. (ft_render::set_mode): Change meaning of yoffset and initialize line_yoffset. (ft_render::process_character): New method. (ft_render::visit(text_element_string)): Use it. (ft_render::visit(text_element_list), ft_render::visit(text_element_subscript), ft_render::visit(text_element_superscript), ft_render::visit(text_element_color), ft_render::visit(text_element_fontsize), ft_render::visit(text_element_fontname), ft_render::visit(text_element_fontstyle), ft_render::visit(text_element_symbol)): New methods. (ft_render::set_color): Use color member instead of red/green/blue. * libinterp/corefcn/txt-eng-ft.h (ft_render::visit(text_element_list), ft_render::visit(text_element_subscript), ft_render::visit(text_element_superscript), ft_render::visit(text_element_color), ft_render::visit(text_element_fontsize), ft_render::visit(text_element_fontname), ft_render::visit(text_element_fontstyle), ft_render::visit(text_element_symbol)): New methods. (ft_render::update_line_bbox, ft_render::process_character): New methods. (ft_render::current_face): Removed method.i (ft_render::font): New member, replaces obsolete ft_render::fonts. (ft_render::line_yoffset): New member. (ft_render::color): New member, replaces obsolete red, green and blue. (ft_render::ft_font::ft_font()): Implement default constructor. (ft_render::ft_font::operator=): Fix incorrect use of FT_Reference_Face return value. (ft_render::ft_font::is_valid): New method. * libinterp/corefcn/txt-eng.h (class text_element_symbol, class text_element_fontname, class text_element_fontsize, class text_element_fontname, class text_element_fontstyle, class text_element_color): Add forward definition. (text_element_symbol::invalid_code): New enum. (text_element_symbol::code): New member. (text_element_symbol::text_element_symbol): Initialize it. (text_element_symbol::get_symbol_code): New method. (text_element_fontstyle::get_fontstyle): New method. (text_element_fontname::get_fontname): Renamed from fontname. (text_element_fontsize::get_fontsize): Renamed from fontsize.

## Copyright (C) 2000-2012 Paul Kienzle
##
## 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} {@var{p} =} factor (@var{q})
## @deftypefnx {Function File} {[@var{p}, @var{n}] =} factor (@var{q})
##
## Return prime factorization of @var{q}.  That is,
## @code{prod (@var{p}) == @var{q}} and every element of @var{p} is a prime
## number.  If @code{@var{q} == 1}, return 1.
##
## With two output arguments, return the unique primes @var{p} and
## their multiplicities.  That is, @code{prod (@var{p} .^ @var{n}) ==
## @var{q}}.
## @seealso{gcd, lcm}
## @end deftypefn

## Author: Paul Kienzle

## 2002-01-28 Paul Kienzle
## * remove recursion; only check existing primes for multiplicity > 1
## * return multiplicity as suggested by Dirk Laurie
## * add error handling

function [x, n] = factor (q)

  if (nargin < 1)
    print_usage ();
  endif

  if (! isscalar (q) || q != fix (q))
    error ("factor: Q must be a scalar integer");
  endif

  ## Special case of no primes less than sqrt(q).
  if (q < 4)
    x = q;
    n = 1;
    return;
  endif

  x = [];
  ## There is at most one prime greater than sqrt(q), and if it exists,
  ## it has multiplicity 1, so no need to consider any factors greater
  ## than sqrt(q) directly. [If there were two factors p1, p2 > sqrt(q),
  ## then q >= p1*p2 > sqrt(q)*sqrt(q) == q. Contradiction.]
  p = primes (sqrt (q));
  while (q > 1)
    ## Find prime factors in remaining q.
    p = p (rem (q, p) == 0);
    if (isempty (p))
      ## Can't be reduced further, so q must itself be a prime.
      p = q;
    endif
    x = [x, p];
    ## Reduce q.
    q = q / prod (p);
  endwhile
  x = sort (x);

  ## Determine muliplicity.
  if (nargout > 1)
    idx = find ([0, x] != [x, 0]);
    x = x(idx(1:length (idx)-1));
    n = diff (idx);
  endif

endfunction


%!assert (factor (1), 1)
%!test
%! for i = 2:20
%!   p = factor (i);
%!   assert (prod (p), i);
%!   assert (all (isprime (p)));
%!   [p,n] = factor (i);
%!   assert (prod (p.^n), i);
%!   assert (all ([0,p] != [p,0]));
%! endfor