/* Pango * pango-bidi-type.c: Bidirectional Character Types * * Copyright (C) 2008 Jürg Billeter * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library 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 * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ /** * SECTION:bidi * @short_description:Types and functions to help with handling bidirectional text * @title:Bidirectional Text * @see_also: * pango_context_get_base_dir(), * pango_context_set_base_dir(), * pango_itemize_with_base_dir() * * Pango supports bidirectional text (like Arabic and Hebrew) automatically. * Some applications however, need some help to correctly handle bidirectional text. * * The #PangoDirection type can be used with pango_context_set_base_dir() to * instruct Pango about direction of text, though in most cases Pango detects * that correctly and automatically. The rest of the facilities in this section * are used internally by Pango already, and are provided to help applications * that need more direct control over bidirectional setting of text. */ #include "config.h" #include #include "pango-bidi-type.h" #include "pango-utils.h" #include "mini-fribidi/fribidi.h" /** * pango_bidi_type_for_unichar: * @ch: a Unicode character * * Determines the normative bidirectional character type of a * character, as specified in the Unicode Character Database. * * A simplified version of this function is available as * pango_unichar_direction(). * * Return value: the bidirectional character type, as used in the * Unicode bidirectional algorithm. * * Since: 1.22 */ PangoBidiType pango_bidi_type_for_unichar (gunichar ch) { FriBidiCharType fribidi_ch_type = fribidi_get_type (ch); switch (fribidi_ch_type) { case FRIBIDI_TYPE_LTR: return PANGO_BIDI_TYPE_L; case FRIBIDI_TYPE_LRE: return PANGO_BIDI_TYPE_LRE; case FRIBIDI_TYPE_LRO: return PANGO_BIDI_TYPE_LRO; case FRIBIDI_TYPE_RTL: return PANGO_BIDI_TYPE_R; case FRIBIDI_TYPE_AL: return PANGO_BIDI_TYPE_AL; case FRIBIDI_TYPE_RLE: return PANGO_BIDI_TYPE_RLE; case FRIBIDI_TYPE_RLO: return PANGO_BIDI_TYPE_RLO; case FRIBIDI_TYPE_PDF: return PANGO_BIDI_TYPE_PDF; case FRIBIDI_TYPE_EN: return PANGO_BIDI_TYPE_EN; case FRIBIDI_TYPE_ES: return PANGO_BIDI_TYPE_ES; case FRIBIDI_TYPE_ET: return PANGO_BIDI_TYPE_ET; case FRIBIDI_TYPE_AN: return PANGO_BIDI_TYPE_AN; case FRIBIDI_TYPE_CS: return PANGO_BIDI_TYPE_CS; case FRIBIDI_TYPE_NSM: return PANGO_BIDI_TYPE_NSM; case FRIBIDI_TYPE_BN: return PANGO_BIDI_TYPE_BN; case FRIBIDI_TYPE_BS: return PANGO_BIDI_TYPE_B; case FRIBIDI_TYPE_SS: return PANGO_BIDI_TYPE_S; case FRIBIDI_TYPE_WS: return PANGO_BIDI_TYPE_WS; case FRIBIDI_TYPE_ON: return PANGO_BIDI_TYPE_ON; default: g_assert_not_reached (); return PANGO_BIDI_TYPE_ON; } } /* Some bidi-related functions */ /** * pango_log2vis_get_embedding_levels: * @text: the text to itemize. * @length: the number of bytes (not characters) to process, or -1 * if @text is nul-terminated and the length should be calculated. * @pbase_dir: input base direction, and output resolved direction. * * This will return the bidirectional embedding levels of the input paragraph * as defined by the Unicode Bidirectional Algorithm available at: * * http://www.unicode.org/reports/tr9/ * * If the input base direction is a weak direction, the direction of the * characters in the text will determine the final resolved direction. * * Return value: a newly allocated array of embedding levels, one item per * character (not byte), that should be freed using g_free. * * Since: 1.4 */ guint8 * pango_log2vis_get_embedding_levels (const gchar *text, int length, PangoDirection *pbase_dir) { FriBidiCharType fribidi_base_dir; guint8 *embedding_levels_list; switch (*pbase_dir) { case PANGO_DIRECTION_LTR: case PANGO_DIRECTION_TTB_RTL: fribidi_base_dir = FRIBIDI_TYPE_L; break; case PANGO_DIRECTION_RTL: case PANGO_DIRECTION_TTB_LTR: fribidi_base_dir = FRIBIDI_TYPE_R; break; case PANGO_DIRECTION_WEAK_RTL: fribidi_base_dir = FRIBIDI_TYPE_WR; break; case PANGO_DIRECTION_WEAK_LTR: case PANGO_DIRECTION_NEUTRAL: default: fribidi_base_dir = FRIBIDI_TYPE_WL; break; } #ifdef FRIBIDI_HAVE_UTF8 { if (length < 0) length = strlen (text); embedding_levels_list = (guint8 *) fribidi_log2vis_get_embedding_levels_new_utf8 (text, length, &fribidi_base_dir); } #else { gunichar *text_ucs4; int n_chars; text_ucs4 = g_utf8_to_ucs4_fast (text, length, &n_chars); embedding_levels_list = g_new (guint8, n_chars); fribidi_log2vis_get_embedding_levels ((FriBidiChar*)text_ucs4, n_chars, &fribidi_base_dir, (FriBidiLevel*)embedding_levels_list); g_free (text_ucs4); } #endif *pbase_dir = (fribidi_base_dir == FRIBIDI_TYPE_L) ? PANGO_DIRECTION_LTR : PANGO_DIRECTION_RTL; return embedding_levels_list; } /** * pango_unichar_direction: * @ch: a Unicode character * * Determines the inherent direction of a character; either * %PANGO_DIRECTION_LTR, %PANGO_DIRECTION_RTL, or * %PANGO_DIRECTION_NEUTRAL. * * This function is useful to categorize characters into left-to-right * letters, right-to-left letters, and everything else. If full * Unicode bidirectional type of a character is needed, * pango_bidi_type_for_unichar() can be used instead. * * Return value: the direction of the character. */ PangoDirection pango_unichar_direction (gunichar ch) { FriBidiCharType fribidi_ch_type = fribidi_get_type (ch); if (!FRIBIDI_IS_STRONG (fribidi_ch_type)) return PANGO_DIRECTION_NEUTRAL; else if (FRIBIDI_IS_RTL (fribidi_ch_type)) return PANGO_DIRECTION_RTL; else return PANGO_DIRECTION_LTR; } /** * pango_get_mirror_char: * @ch: a Unicode character * @mirrored_ch: location to store the mirrored character * * If @ch has the Unicode mirrored property and there is another Unicode * character that typically has a glyph that is the mirror image of @ch's * glyph, puts that character in the address pointed to by @mirrored_ch. * * Use g_unichar_get_mirror_char() instead; the docs for that function * provide full details. * * Return value: %TRUE if @ch has a mirrored character and @mirrored_ch is * filled in, %FALSE otherwise **/ gboolean pango_get_mirror_char (gunichar ch, gunichar *mirrored_ch) { return g_unichar_get_mirror_char (ch, mirrored_ch); }