diff options
Diffstat (limited to 'libass/ass_shaper.c')
| -rw-r--r-- | libass/ass_shaper.c | 174 |
1 files changed, 170 insertions, 4 deletions
diff --git a/libass/ass_shaper.c b/libass/ass_shaper.c index 6ffc083..87b6c6d 100644 --- a/libass/ass_shaper.c +++ b/libass/ass_shaper.c @@ -412,6 +412,107 @@ static hb_font_t *get_hb_font(ASS_Shaper *shaper, GlyphInfo *info) } /** + * \brief Map script to default language. + * + * This maps a script to a language, if a script has a representative + * language it is typically used with. Otherwise, the invalid language + * is returned. + * + * The mapping is similar to Pango's pango-language.c. + * + * \param script script tag + * \return language tag + */ +static hb_language_t script_to_language(hb_script_t script) +{ + switch (script) { + // Unicode 1.1 + case HB_SCRIPT_ARABIC: return hb_language_from_string("ar", -1); break; + case HB_SCRIPT_ARMENIAN: return hb_language_from_string("hy", -1); break; + case HB_SCRIPT_BENGALI: return hb_language_from_string("bn", -1); break; + case HB_SCRIPT_CANADIAN_ABORIGINAL: return hb_language_from_string("iu", -1); break; + case HB_SCRIPT_CHEROKEE: return hb_language_from_string("chr", -1); break; + case HB_SCRIPT_COPTIC: return hb_language_from_string("cop", -1); break; + case HB_SCRIPT_CYRILLIC: return hb_language_from_string("ru", -1); break; + case HB_SCRIPT_DEVANAGARI: return hb_language_from_string("hi", -1); break; + case HB_SCRIPT_GEORGIAN: return hb_language_from_string("ka", -1); break; + case HB_SCRIPT_GREEK: return hb_language_from_string("el", -1); break; + case HB_SCRIPT_GUJARATI: return hb_language_from_string("gu", -1); break; + case HB_SCRIPT_GURMUKHI: return hb_language_from_string("pa", -1); break; + case HB_SCRIPT_HANGUL: return hb_language_from_string("ko", -1); break; + case HB_SCRIPT_HEBREW: return hb_language_from_string("he", -1); break; + case HB_SCRIPT_HIRAGANA: return hb_language_from_string("ja", -1); break; + case HB_SCRIPT_KANNADA: return hb_language_from_string("kn", -1); break; + case HB_SCRIPT_KATAKANA: return hb_language_from_string("ja", -1); break; + case HB_SCRIPT_LAO: return hb_language_from_string("lo", -1); break; + case HB_SCRIPT_LATIN: return hb_language_from_string("en", -1); break; + case HB_SCRIPT_MALAYALAM: return hb_language_from_string("ml", -1); break; + case HB_SCRIPT_MONGOLIAN: return hb_language_from_string("mn", -1); break; + case HB_SCRIPT_ORIYA: return hb_language_from_string("or", -1); break; + case HB_SCRIPT_SYRIAC: return hb_language_from_string("syr", -1); break; + case HB_SCRIPT_TAMIL: return hb_language_from_string("ta", -1); break; + case HB_SCRIPT_TELUGU: return hb_language_from_string("te", -1); break; + case HB_SCRIPT_THAI: return hb_language_from_string("th", -1); break; + + // Unicode 2.0 + case HB_SCRIPT_TIBETAN: return hb_language_from_string("bo", -1); break; + + // Unicode 3.0 + case HB_SCRIPT_ETHIOPIC: return hb_language_from_string("am", -1); break; + case HB_SCRIPT_KHMER: return hb_language_from_string("km", -1); break; + case HB_SCRIPT_MYANMAR: return hb_language_from_string("my", -1); break; + case HB_SCRIPT_SINHALA: return hb_language_from_string("si", -1); break; + case HB_SCRIPT_THAANA: return hb_language_from_string("dv", -1); break; + + // Unicode 3.2 + case HB_SCRIPT_BUHID: return hb_language_from_string("bku", -1); break; + case HB_SCRIPT_HANUNOO: return hb_language_from_string("hnn", -1); break; + case HB_SCRIPT_TAGALOG: return hb_language_from_string("tl", -1); break; + case HB_SCRIPT_TAGBANWA: return hb_language_from_string("tbw", -1); break; + + // Unicode 4.0 + case HB_SCRIPT_UGARITIC: return hb_language_from_string("uga", -1); break; + + // Unicode 4.1 + case HB_SCRIPT_BUGINESE: return hb_language_from_string("bug", -1); break; + case HB_SCRIPT_OLD_PERSIAN: return hb_language_from_string("peo", -1); break; + case HB_SCRIPT_SYLOTI_NAGRI: return hb_language_from_string("syl", -1); break; + + // Unicode 5.0 + case HB_SCRIPT_NKO: return hb_language_from_string("nko", -1); break; + + // no representative language exists + default: return HB_LANGUAGE_INVALID; break; + } +} + +/** + * \brief Determine language to be used for shaping a run. + * + * \param shaper shaper instance + * \param script script tag associated with run + * \return language tag + */ +static hb_language_t +hb_shaper_get_run_language(ASS_Shaper *shaper, hb_script_t script) +{ + hb_language_t lang; + + // override set, use it + if (shaper->language != HB_LANGUAGE_INVALID) + return shaper->language; + + // get default language for given script + lang = script_to_language(script); + + // no dice, use system default + if (lang == HB_LANGUAGE_INVALID) + lang = hb_language_get_default(); + + return lang; +} + +/** * \brief Shape event text with HarfBuzz. Full OpenType shaping. * \param glyphs glyph clusters * \param len number of clusters @@ -433,6 +534,7 @@ static void shape_harfbuzz(ASS_Shaper *shaper, GlyphInfo *glyphs, size_t len) int k = i; int level = glyphs[i].shape_run_id; int direction = shaper->emblevels[k] % 2; + hb_script_t script = glyphs[i].script; while (i < (len - 1) && level == glyphs[i+1].shape_run_id) i++; runs[run].offset = k; @@ -443,7 +545,9 @@ static void shape_harfbuzz(ASS_Shaper *shaper, GlyphInfo *glyphs, size_t len) hb_buffer_pre_allocate(runs[run].buf, i - k + 1); hb_buffer_set_direction(runs[run].buf, direction ? HB_DIRECTION_RTL : HB_DIRECTION_LTR); - hb_buffer_set_language(runs[run].buf, shaper->language); + hb_buffer_set_language(runs[run].buf, + hb_shaper_get_run_language(shaper, script)); + hb_buffer_set_script(runs[run].buf, script); hb_buffer_add_utf32(runs[run].buf, shaper->event_text + k, i - k + 1, 0, i - k + 1); hb_shape(runs[run].font, runs[run].buf, shaper->features, @@ -496,6 +600,56 @@ static void shape_harfbuzz(ASS_Shaper *shaper, GlyphInfo *glyphs, size_t len) } } + +/** + * \brief Determine script property of all characters. Characters of script + * common and inherited get their script from their context. + * + */ +void ass_shaper_determine_script(ASS_Shaper *shaper, GlyphInfo *glyphs, + size_t len) +{ + int i; + int backwards_scan = 0; + hb_unicode_funcs_t *ufuncs = hb_unicode_funcs_get_default(); + hb_script_t last_script = HB_SCRIPT_UNKNOWN; + + // determine script (forward scan) + for (i = 0; i < len; i++) { + GlyphInfo *info = glyphs + i; + info->script = hb_unicode_script(ufuncs, info->symbol); + + // common/inherit codepoints inherit script from context + if (info->script == HB_SCRIPT_COMMON || + info->script == HB_SCRIPT_INHERITED) { + // unknown is not a valid context + if (last_script != HB_SCRIPT_UNKNOWN) + info->script = last_script; + else + // do a backwards scan to check if next codepoint + // contains a valid script for context + backwards_scan = 1; + } else { + last_script = info->script; + } + } + + // determine script (backwards scan, if needed) + last_script = HB_SCRIPT_UNKNOWN; + for (i = len - 1; i >= 0 && backwards_scan; i--) { + GlyphInfo *info = glyphs + i; + + // common/inherit codepoints inherit script from context + if (info->script == HB_SCRIPT_COMMON || + info->script == HB_SCRIPT_INHERITED) { + // unknown script is not a valid context + if (last_script != HB_SCRIPT_UNKNOWN) + info->script = last_script; + } else { + last_script = info->script; + } + } +} #endif /** @@ -546,6 +700,11 @@ void ass_shaper_find_runs(ASS_Shaper *shaper, ASS_Renderer *render_priv, int i; int shape_run = 0; +#ifdef CONFIG_HARFBUZZ + ass_shaper_determine_script(shaper, glyphs, len); +#endif + + // find appropriate fonts for the shape runs for (i = 0; i < len; i++) { GlyphInfo *last = glyphs + i - 1; GlyphInfo *info = glyphs + i; @@ -558,11 +717,11 @@ void ass_shaper_find_runs(ASS_Shaper *shaper, ASS_Renderer *render_priv, // shape runs share the same font face and size if (i > 0 && (last->font != info->font || last->font_size != info->font_size || - last->face_index != info->face_index)) + last->face_index != info->face_index || + last->script != info->script)) shape_run++; info->shape_run_id = shape_run; } - } /** @@ -582,7 +741,14 @@ void ass_shaper_set_base_direction(ASS_Shaper *shaper, FriBidiParType dir) void ass_shaper_set_language(ASS_Shaper *shaper, const char *code) { #ifdef CONFIG_HARFBUZZ - shaper->language = hb_language_from_string(code, -1); + hb_language_t lang; + + if (code) + lang = hb_language_from_string(code, -1); + else + lang = HB_LANGUAGE_INVALID; + + shaper->language = lang; #endif } |