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Diffstat (limited to 'gfx/harfbuzz/src/hb-ot-shape-complex-arabic-fallback.hh')
| -rw-r--r-- | gfx/harfbuzz/src/hb-ot-shape-complex-arabic-fallback.hh | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-ot-shape-complex-arabic-fallback.hh b/gfx/harfbuzz/src/hb-ot-shape-complex-arabic-fallback.hh new file mode 100644 index 000000000..d97d28521 --- /dev/null +++ b/gfx/harfbuzz/src/hb-ot-shape-complex-arabic-fallback.hh @@ -0,0 +1,354 @@ +/* + * Copyright © 2012 Google, Inc. + * + * This is part of HarfBuzz, a text shaping library. + * + * Permission is hereby granted, without written agreement and without + * license or royalty fees, to use, copy, modify, and distribute this + * software and its documentation for any purpose, provided that the + * above copyright notice and the following two paragraphs appear in + * all copies of this software. + * + * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR + * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES + * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN + * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH + * DAMAGE. + * + * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, + * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND + * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS + * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO + * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. + * + * Google Author(s): Behdad Esfahbod + */ + +#ifndef HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH +#define HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH + +#include "hb-private.hh" + +#include "hb-ot-shape-private.hh" +#include "hb-ot-layout-gsub-table.hh" + + +/* Features ordered the same as the entries in shaping_table rows, + * followed by rlig. Don't change. */ +static const hb_tag_t arabic_fallback_features[] = +{ + HB_TAG('i','n','i','t'), + HB_TAG('m','e','d','i'), + HB_TAG('f','i','n','a'), + HB_TAG('i','s','o','l'), + HB_TAG('r','l','i','g'), +}; + +static OT::SubstLookup * +arabic_fallback_synthesize_lookup_single (const hb_ot_shape_plan_t *plan HB_UNUSED, + hb_font_t *font, + unsigned int feature_index) +{ + OT::GlyphID glyphs[SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1]; + OT::GlyphID substitutes[SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1]; + unsigned int num_glyphs = 0; + + /* Populate arrays */ + for (hb_codepoint_t u = SHAPING_TABLE_FIRST; u < SHAPING_TABLE_LAST + 1; u++) + { + hb_codepoint_t s = shaping_table[u - SHAPING_TABLE_FIRST][feature_index]; + hb_codepoint_t u_glyph, s_glyph; + + if (!s || + !hb_font_get_glyph (font, u, 0, &u_glyph) || + !hb_font_get_glyph (font, s, 0, &s_glyph) || + u_glyph == s_glyph || + u_glyph > 0xFFFFu || s_glyph > 0xFFFFu) + continue; + + glyphs[num_glyphs].set (u_glyph); + substitutes[num_glyphs].set (s_glyph); + + num_glyphs++; + } + + if (!num_glyphs) + return NULL; + + /* Bubble-sort or something equally good! + * May not be good-enough for presidential candidate interviews, but good-enough for us... */ + hb_stable_sort (&glyphs[0], num_glyphs, OT::GlyphID::cmp, &substitutes[0]); + + OT::Supplier<OT::GlyphID> glyphs_supplier (glyphs, num_glyphs); + OT::Supplier<OT::GlyphID> substitutes_supplier (substitutes, num_glyphs); + + /* Each glyph takes four bytes max, and there's some overhead. */ + char buf[(SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1) * 4 + 128]; + OT::hb_serialize_context_t c (buf, sizeof (buf)); + OT::SubstLookup *lookup = c.start_serialize<OT::SubstLookup> (); + bool ret = lookup->serialize_single (&c, + OT::LookupFlag::IgnoreMarks, + glyphs_supplier, + substitutes_supplier, + num_glyphs); + c.end_serialize (); + /* TODO sanitize the results? */ + + return ret ? c.copy<OT::SubstLookup> () : NULL; +} + +static OT::SubstLookup * +arabic_fallback_synthesize_lookup_ligature (const hb_ot_shape_plan_t *plan HB_UNUSED, + hb_font_t *font) +{ + OT::GlyphID first_glyphs[ARRAY_LENGTH_CONST (ligature_table)]; + unsigned int first_glyphs_indirection[ARRAY_LENGTH_CONST (ligature_table)]; + unsigned int ligature_per_first_glyph_count_list[ARRAY_LENGTH_CONST (first_glyphs)]; + unsigned int num_first_glyphs = 0; + + /* We know that all our ligatures are 2-component */ + OT::GlyphID ligature_list[ARRAY_LENGTH_CONST (first_glyphs) * ARRAY_LENGTH_CONST(ligature_table[0].ligatures)]; + unsigned int component_count_list[ARRAY_LENGTH_CONST (ligature_list)]; + OT::GlyphID component_list[ARRAY_LENGTH_CONST (ligature_list) * 1/* One extra component per ligature */]; + unsigned int num_ligatures = 0; + + /* Populate arrays */ + + /* Sort out the first-glyphs */ + for (unsigned int first_glyph_idx = 0; first_glyph_idx < ARRAY_LENGTH (first_glyphs); first_glyph_idx++) + { + hb_codepoint_t first_u = ligature_table[first_glyph_idx].first; + hb_codepoint_t first_glyph; + if (!hb_font_get_glyph (font, first_u, 0, &first_glyph)) + continue; + first_glyphs[num_first_glyphs].set (first_glyph); + ligature_per_first_glyph_count_list[num_first_glyphs] = 0; + first_glyphs_indirection[num_first_glyphs] = first_glyph_idx; + num_first_glyphs++; + } + hb_stable_sort (&first_glyphs[0], num_first_glyphs, OT::GlyphID::cmp, &first_glyphs_indirection[0]); + + /* Now that the first-glyphs are sorted, walk again, populate ligatures. */ + for (unsigned int i = 0; i < num_first_glyphs; i++) + { + unsigned int first_glyph_idx = first_glyphs_indirection[i]; + + for (unsigned int second_glyph_idx = 0; second_glyph_idx < ARRAY_LENGTH (ligature_table[0].ligatures); second_glyph_idx++) + { + hb_codepoint_t second_u = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].second; + hb_codepoint_t ligature_u = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].ligature; + hb_codepoint_t second_glyph, ligature_glyph; + if (!second_u || + !hb_font_get_glyph (font, second_u, 0, &second_glyph) || + !hb_font_get_glyph (font, ligature_u, 0, &ligature_glyph)) + continue; + + ligature_per_first_glyph_count_list[i]++; + + ligature_list[num_ligatures].set (ligature_glyph); + component_count_list[num_ligatures] = 2; + component_list[num_ligatures].set (second_glyph); + num_ligatures++; + } + } + + if (!num_ligatures) + return NULL; + + OT::Supplier<OT::GlyphID> first_glyphs_supplier (first_glyphs, num_first_glyphs); + OT::Supplier<unsigned int > ligature_per_first_glyph_count_supplier (ligature_per_first_glyph_count_list, num_first_glyphs); + OT::Supplier<OT::GlyphID> ligatures_supplier (ligature_list, num_ligatures); + OT::Supplier<unsigned int > component_count_supplier (component_count_list, num_ligatures); + OT::Supplier<OT::GlyphID> component_supplier (component_list, num_ligatures); + + /* 16 bytes per ligature ought to be enough... */ + char buf[ARRAY_LENGTH_CONST (ligature_list) * 16 + 128]; + OT::hb_serialize_context_t c (buf, sizeof (buf)); + OT::SubstLookup *lookup = c.start_serialize<OT::SubstLookup> (); + bool ret = lookup->serialize_ligature (&c, + OT::LookupFlag::IgnoreMarks, + first_glyphs_supplier, + ligature_per_first_glyph_count_supplier, + num_first_glyphs, + ligatures_supplier, + component_count_supplier, + component_supplier); + + c.end_serialize (); + /* TODO sanitize the results? */ + + return ret ? c.copy<OT::SubstLookup> () : NULL; +} + +static OT::SubstLookup * +arabic_fallback_synthesize_lookup (const hb_ot_shape_plan_t *plan, + hb_font_t *font, + unsigned int feature_index) +{ + if (feature_index < 4) + return arabic_fallback_synthesize_lookup_single (plan, font, feature_index); + else + return arabic_fallback_synthesize_lookup_ligature (plan, font); +} + +#define ARABIC_FALLBACK_MAX_LOOKUPS 5 + +struct arabic_fallback_plan_t +{ + ASSERT_POD (); + + unsigned int num_lookups; + bool free_lookups; + + hb_mask_t mask_array[ARABIC_FALLBACK_MAX_LOOKUPS]; + OT::SubstLookup *lookup_array[ARABIC_FALLBACK_MAX_LOOKUPS]; + hb_ot_layout_lookup_accelerator_t accel_array[ARABIC_FALLBACK_MAX_LOOKUPS]; +}; + +static const arabic_fallback_plan_t arabic_fallback_plan_nil = {}; + +#if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(HB_NO_WIN1256) +#define HB_WITH_WIN1256 +#endif + +#ifdef HB_WITH_WIN1256 +#include "hb-ot-shape-complex-arabic-win1256.hh" +#endif + +struct ManifestLookup { + OT::Tag tag; + OT::OffsetTo<OT::SubstLookup> lookupOffset; +}; +typedef OT::ArrayOf<ManifestLookup> Manifest; + +static bool +arabic_fallback_plan_init_win1256 (arabic_fallback_plan_t *fallback_plan, + const hb_ot_shape_plan_t *plan, + hb_font_t *font) +{ +#ifdef HB_WITH_WIN1256 + /* Does this font look like it's Windows-1256-encoded? */ + hb_codepoint_t g; + if (!(hb_font_get_glyph (font, 0x0627u, 0, &g) && g == 199 /* ALEF */ && + hb_font_get_glyph (font, 0x0644u, 0, &g) && g == 225 /* LAM */ && + hb_font_get_glyph (font, 0x0649u, 0, &g) && g == 236 /* ALEF MAKSURA */ && + hb_font_get_glyph (font, 0x064Au, 0, &g) && g == 237 /* YEH */ && + hb_font_get_glyph (font, 0x0652u, 0, &g) && g == 250 /* SUKUN */)) + return false; + + const Manifest &manifest = reinterpret_cast<const Manifest&> (arabic_win1256_gsub_lookups.manifest); + ASSERT_STATIC (sizeof (arabic_win1256_gsub_lookups.manifestData) / sizeof (ManifestLookup) + <= ARABIC_FALLBACK_MAX_LOOKUPS); + /* TODO sanitize the table? */ + + unsigned j = 0; + unsigned int count = manifest.len; + for (unsigned int i = 0; i < count; i++) + { + fallback_plan->mask_array[j] = plan->map.get_1_mask (manifest[i].tag); + if (fallback_plan->mask_array[j]) + { + fallback_plan->lookup_array[j] = const_cast<OT::SubstLookup*> (&(&manifest+manifest[i].lookupOffset)); + if (fallback_plan->lookup_array[j]) + { + fallback_plan->accel_array[j].init (*fallback_plan->lookup_array[j]); + j++; + } + } + } + + fallback_plan->num_lookups = j; + fallback_plan->free_lookups = false; + + return j > 0; +#else + return false; +#endif +} + +static bool +arabic_fallback_plan_init_unicode (arabic_fallback_plan_t *fallback_plan, + const hb_ot_shape_plan_t *plan, + hb_font_t *font) +{ + ASSERT_STATIC (ARRAY_LENGTH_CONST(arabic_fallback_features) <= ARABIC_FALLBACK_MAX_LOOKUPS); + unsigned int j = 0; + for (unsigned int i = 0; i < ARRAY_LENGTH(arabic_fallback_features) ; i++) + { + fallback_plan->mask_array[j] = plan->map.get_1_mask (arabic_fallback_features[i]); + if (fallback_plan->mask_array[j]) + { + fallback_plan->lookup_array[j] = arabic_fallback_synthesize_lookup (plan, font, i); + if (fallback_plan->lookup_array[j]) + { + fallback_plan->accel_array[j].init (*fallback_plan->lookup_array[j]); + j++; + } + } + } + + fallback_plan->num_lookups = j; + fallback_plan->free_lookups = true; + + return j > 0; +} + +static arabic_fallback_plan_t * +arabic_fallback_plan_create (const hb_ot_shape_plan_t *plan, + hb_font_t *font) +{ + arabic_fallback_plan_t *fallback_plan = (arabic_fallback_plan_t *) calloc (1, sizeof (arabic_fallback_plan_t)); + if (unlikely (!fallback_plan)) + return const_cast<arabic_fallback_plan_t *> (&arabic_fallback_plan_nil); + + fallback_plan->num_lookups = 0; + fallback_plan->free_lookups = false; + + /* Try synthesizing GSUB table using Unicode Arabic Presentation Forms, + * in case the font has cmap entries for the presentation-forms characters. */ + if (arabic_fallback_plan_init_unicode (fallback_plan, plan, font)) + return fallback_plan; + + /* See if this looks like a Windows-1256-encoded font. If it does, use a + * hand-coded GSUB table. */ + if (arabic_fallback_plan_init_win1256 (fallback_plan, plan, font)) + return fallback_plan; + + free (fallback_plan); + return const_cast<arabic_fallback_plan_t *> (&arabic_fallback_plan_nil); +} + +static void +arabic_fallback_plan_destroy (arabic_fallback_plan_t *fallback_plan) +{ + if (!fallback_plan || fallback_plan == &arabic_fallback_plan_nil) + return; + + for (unsigned int i = 0; i < fallback_plan->num_lookups; i++) + if (fallback_plan->lookup_array[i]) + { + fallback_plan->accel_array[i].fini (); + if (fallback_plan->free_lookups) + free (fallback_plan->lookup_array[i]); + } + + free (fallback_plan); +} + +static void +arabic_fallback_plan_shape (arabic_fallback_plan_t *fallback_plan, + hb_font_t *font, + hb_buffer_t *buffer) +{ + OT::hb_apply_context_t c (0, font, buffer); + for (unsigned int i = 0; i < fallback_plan->num_lookups; i++) + if (fallback_plan->lookup_array[i]) { + c.set_lookup_mask (fallback_plan->mask_array[i]); + hb_ot_layout_substitute_lookup (&c, + *fallback_plan->lookup_array[i], + fallback_plan->accel_array[i]); + } +} + + +#endif /* HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH */ |