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Diffstat (limited to 'trunk/modules/arabic/arabic-lang.c')
| -rw-r--r-- | trunk/modules/arabic/arabic-lang.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/trunk/modules/arabic/arabic-lang.c b/trunk/modules/arabic/arabic-lang.c new file mode 100644 index 00000000..7022b04e --- /dev/null +++ b/trunk/modules/arabic/arabic-lang.c @@ -0,0 +1,152 @@ +/* Pango + * arabic-lang.c: + * + * Copyright (C) 2006 Red Hat Software + * Copyright (C) 2006 Sharif FarsiWeb, Inc. + * Authors: Behdad Esfahbod <besfahbo@redhat.com> + * Roozbeh Pournader <roozbeh@farsiweb.info> + * + * 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. + */ + +#include <config.h> +#include <string.h> + +#include "pango-engine.h" +#include "pango-break.h" + +/* No extra fields needed */ +typedef PangoEngineLang ArabicEngineLang; +typedef PangoEngineLangClass ArabicEngineLangClass ; + +#define SCRIPT_ENGINE_NAME "ArabicScriptEngineLang" +#define RENDER_TYPE PANGO_RENDER_TYPE_NONE + +static PangoEngineScriptInfo arabic_scripts[] = { + { PANGO_SCRIPT_ARABIC, "*" }, +}; + +static PangoEngineInfo script_engines[] = { + { + SCRIPT_ENGINE_NAME, + PANGO_ENGINE_TYPE_LANG, + RENDER_TYPE, + arabic_scripts, G_N_ELEMENTS(arabic_scripts) + } +}; + + +#define ALEF_WITH_MADDA_ABOVE 0x0622 +#define YEH_WITH_HAMZA_ABOVE 0x0626 +#define ALEF 0x0627 +#define WAW 0x0648 +#define YEH 0x064A + +#define MADDAH_ABOVE 0x0653 +#define HAMZA_ABOVE 0x0654 +#define HAMZA_BELOW 0x0655 + +/* + * Arabic characters with canonical decompositions that are not just + * ligatures. The characters U+06C0, U+06C2, and U+06D3 are intentionally + * excluded as they are marked as "not an independent letter" in Unicode + * Character Database's NamesList.txt + */ +#define IS_COMPOSITE(c) (ALEF_WITH_MADDA_ABOVE <= (c) && (c) <= YEH_WITH_HAMZA_ABOVE) + +/* If a character is the second part of a composite Arabic character with an Alef */ +#define IS_COMPOSITE_WITH_ALEF(c) (MADDAH_ABOVE <= (c) && (c) <= HAMZA_BELOW) + +static void +arabic_engine_break (PangoEngineLang *engine, + const char *text, + int length, + PangoAnalysis *analysis, + PangoLogAttr *attrs, + int attrs_len) +{ + int i; + const char *p; + gunichar prev_wc, this_wc; + + /* See http://bugzilla.gnome.org/show_bug.cgi?id=350132 for issues this + * module tries to solve. + */ + + for (p = text, i = 0, prev_wc = 0; + p < text + length; + p = g_utf8_next_char (p), i++, prev_wc = this_wc) + { + this_wc = g_utf8_get_char (p); + + /* + * Unset backspace_deletes_character for various combinations. + * + * A few more combinations may need to be handled here, but are not + * handled yet, as expectations of users is not known or may differ + * among different languages or users: + * some letters combined with U+0658 ARABIC MARK NOON GHUNNA; + * combinations considered one letter in Azerbaijani (WAW+SUKUN and + * FARSI_YEH+HAMZA_ABOVE); combinations of YEH and ALEF_MAKSURA with + * HAMZA_BELOW (Qur'anic); TATWEEL+HAMZA_ABOVE (Qur'anic). + * + * FIXME: Ordering these in some other way may lower the time spent here, or not. + */ + if (G_UNLIKELY ( + IS_COMPOSITE (this_wc) || + (prev_wc == ALEF && IS_COMPOSITE_WITH_ALEF (this_wc)) || + (this_wc == HAMZA_ABOVE && (prev_wc == WAW || prev_wc == YEH)) + )) + attrs[i+1].backspace_deletes_character = FALSE; + } +} + +static void +arabic_engine_lang_class_init (PangoEngineLangClass *class) +{ + class->script_break = arabic_engine_break; +} + +PANGO_ENGINE_LANG_DEFINE_TYPE (ArabicEngineLang, arabic_engine_lang, + arabic_engine_lang_class_init, NULL) + +void +PANGO_MODULE_ENTRY(init) (GTypeModule *module) +{ + arabic_engine_lang_register_type (module); +} + +void +PANGO_MODULE_ENTRY(exit) (void) +{ +} + +void +PANGO_MODULE_ENTRY(list) (PangoEngineInfo **engines, + int *n_engines) +{ + *engines = script_engines; + *n_engines = G_N_ELEMENTS (script_engines); +} + +PangoEngine * +PANGO_MODULE_ENTRY(create) (const char *id) +{ + if (!strcmp (id, SCRIPT_ENGINE_NAME)) + return g_object_new (arabic_engine_lang_type, NULL); + else + return NULL; +} |