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Diffstat (limited to 'bidi.cc')
| -rw-r--r-- | bidi.cc | 136 |
1 files changed, 136 insertions, 0 deletions
@@ -0,0 +1,136 @@ +// Copyright (C) 2003 Mooffie <mooffie@typo.co.il> +// +// This program 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 2 of the License, or +// (at your option) any later version. +// +// This program 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 this program; if not, write to the Free Software +// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. + +#include <config.h> + +#include "bidi.h" +#include "dbg.h" + +static ctype_t fribidi_dir(direction_t dir) +{ + switch (dir) { + case dirLTR: return FRIBIDI_TYPE_LTR; + case dirRTL: return FRIBIDI_TYPE_RTL; + default: return FRIBIDI_TYPE_ON; + } +} + +void BiDi::get_embedding_levels(unichar *str, idx_t len, + direction_t dir, + level_t *levels, + int line_breaks_count, + idx_t *line_breaks, + bool disable_bidi) +{ + if (disable_bidi) { + for (idx_t i = len-1; i >= 0; i--) + levels[i] = (dir == dirRTL) ? 1 :0; + } else { + ctype_t base_dir = fribidi_dir(dir); + fribidi_log2vis_get_embedding_levels(str, len, &base_dir, levels); + } + + // Do rule L1.4 of TR9: wspaces at end of lines. + level_t para_embedding_level = (dir == dirRTL ? 1 : 0); + int prev_line_break = 0; + for (int i = 0; i < line_breaks_count; i++) { + int pos = (int)line_breaks[i] - 1; + while (pos >= prev_line_break && is_space(str[pos])) { + levels[pos] = para_embedding_level; + pos--; + } + prev_line_break = line_breaks[i]; + } +} + +static void xsimple_log2vis(unichar *str, idx_t len, direction_t dir, + unichar *dest) +{ + ctype_t base_dir = fribidi_dir(dir); + fribidi_log2vis(str, len, &base_dir, dest, NULL, NULL, NULL); +} + +void BiDi::simple_log2vis(unistring &str, direction_t dir, unistring &dest) +{ + dest.resize(str.size() + 1); // fribidi_log2vis needs "+1" !!!!!!!!!!!!! + xsimple_log2vis(str.begin(), str.size(), dir, dest.begin()); + dest.resize(str.size()); +} + +// determine_base_dir() - determines the base direction of a string. +// We provide the user with several algorithms. algoUnicode is described +// in P2,3 of TR9. +// +// algoContext's implementation is divided into two: half is here and +// the other half is in EditBox::calc_contextual_dirs(). See documentation +// there. + +direction_t BiDi::determine_base_dir(unichar *str, idx_t len, + diralgo_t dir_algo) +{ + ctype_t ctype; + switch (dir_algo) { + case algoContextRTL: + { + // - if there's any RTL letter, set direction to LTR; + // - else: if there's any LTR letter, set direction to LTR; + // - else: set direction to neutral. + bool found_LTR = false; + for (idx_t i = 0; i < len; i++) { + ctype = fribidi_get_type(str[i]); + if (FRIBIDI_IS_LETTER(ctype)) { + if (FRIBIDI_IS_RTL(ctype)) + return dirRTL; + else + found_LTR = true; + } + } + if (found_LTR) + return dirLTR; + else + return dirN; + } + + case algoUnicode: + case algoContextStrong: + { + // directionality is determined by the first strong letter. + for (idx_t i = 0; i < len; i++) { + ctype = fribidi_get_type(str[i]); + if (FRIBIDI_IS_LETTER(ctype)) { + if (FRIBIDI_IS_RTL(ctype)) + return dirRTL; + else + return dirLTR; + } + } + if (dir_algo == algoContextStrong) + return dirN; + else + return dirLTR; + } + + case algoForceRTL: + + return dirRTL; + + case algoForceLTR: + default: + + return dirLTR; + }; +} + |