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) 2006-2012 William Poetra Yoga Hadisoeseno
##
## 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} {} strtrunc (@var{s}, @var{n})
## Truncate the character string @var{s} to length @var{n}.  If @var{s}
## is a character matrix, then the number of columns is adjusted.
## If @var{s} is a cell array of strings, then the operation is performed
## on each cell element and the new cell array is returned.
## @end deftypefn

function s = strtrunc (s, n)

  if (nargin != 2)
    print_usage ();
  endif

  n = fix (n);
  if (! isscalar (n) || n < 0)
    error ("strtrunc: length N must be a positive integer (N >= 0)");
  endif

  if (ischar (s))
    if (n < columns (s))
      s = s(:, 1:n);
    endif
  elseif (iscellstr (s))
    ## Convoluted approach converts cellstr to char matrix, trims the character
    ## matrix using indexing, and then converts back to cellstr with mat2cell.
    ## This approach is 24X faster than using cellfun with call to strtrunc
    idx = cellfun ("size", s, 2) > n;
    rows = cellfun ("size", s(idx), 1);
    if (! isempty (rows))
      s(idx) = mat2cell (char (s(idx))(:, 1:n), rows);
    endif
  else
    error ("strtrunc: S must be a character string or a cell array of strings");
  endif

endfunction


%!assert (strtrunc ("abcdefg", 4), "abcd")
%!assert (strtrunc ("abcdefg", 10), "abcdefg")
%!assert (strtrunc (char ("abcdef", "fedcba"), 3), ["abc"; "fed"])
%!assert (strtrunc ({"abcdef", "fedcba"}, 3), {"abc", "fed"})
%!assert (strtrunc ({"", "1", "21", "321"}, 1), {"", "1", "2", "3"})
%!assert (strtrunc ({"1", "", "2"}, 1), {"1", "", "2"})
%!test
%! cstr = {"line1"; ["line2"; "line3"]; "line4"};
%! y = strtrunc (cstr, 4);
%! assert (size (y), [3, 1]); 
%! assert (size (y{2}), [2, 4]); 
%! assert (y{2}, repmat ("line", 2, 1));

%% Test input validation
%!error strtrunc ()
%!error strtrunc ("abcd")
%!error strtrunc ("abcd", 4, 5)
%!error <N must be a positive integer> strtrunc ("abcd", ones (2,2))
%!error <N must be a positive integer> strtrunc ("abcd", -1)
%!error <S must be a character string or a cell array of strings> strtrunc (1, 1)