Edit
kc3-lang/harfbuzz/src/hb-ot-shape-complex-arabic-fallback.hh
Behdad Esfahbod
- src/hb-ot-shape-complex-arabic-fallback.hh
-
/* * 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 */