1 /* 2 * Copyright 2012 Google, Inc. 3 * 4 * This is part of HarfBuzz, a text shaping library. 5 * 6 * Permission is hereby granted, without written agreement and without 7 * license or royalty fees, to use, copy, modify, and distribute this 8 * software and its documentation for any purpose, provided that the 9 * above copyright notice and the following two paragraphs appear in 10 * all copies of this software. 11 * 12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR 13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES 14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN 15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH 16 * DAMAGE. 17 * 18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, 19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS 21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO 22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. 23 * 24 * Google Author(s): Behdad Esfahbod 25 */ 26 27 #ifndef HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH 28 #define HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH 29 30 #include "hb-private.hh" 31 32 #include "hb-ot-shape-private.hh" 33 #include "hb-ot-layout-gsub-table.hh" 34 35 36 static const hb_tag_t arabic_fallback_features[] = 37 { 38 HB_TAG('i','n','i','t'), 39 HB_TAG('m','e','d','i'), 40 HB_TAG('f','i','n','a'), 41 HB_TAG('i','s','o','l'), 42 HB_TAG('r','l','i','g'), 43 }; 44 45 /* Same order as the fallback feature array */ 46 enum { 47 FALLBACK_INIT, 48 FALLBACK_MEDI, 49 FALLBACK_FINA, 50 FALLBACK_ISOL, 51 FALLBACK_RLIG, 52 ARABIC_NUM_FALLBACK_FEATURES 53 }; 54 55 static OT::SubstLookup * 56 arabic_fallback_synthesize_lookup_single (const hb_ot_shape_plan_t *plan HB_UNUSED, 57 hb_font_t *font, 58 unsigned int feature_index) 59 { 60 OT::GlyphID glyphs[SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1]; 61 OT::GlyphID substitutes[SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1]; 62 unsigned int num_glyphs = 0; 63 64 /* Populate arrays */ 65 for (hb_codepoint_t u = SHAPING_TABLE_FIRST; u < SHAPING_TABLE_LAST + 1; u++) 66 { 67 hb_codepoint_t s = shaping_table[u - SHAPING_TABLE_FIRST][feature_index]; 68 hb_codepoint_t u_glyph, s_glyph; 69 70 if (!s || 71 !hb_font_get_glyph (font, u, 0, &u_glyph) || 72 !hb_font_get_glyph (font, s, 0, &s_glyph) || 73 u_glyph == s_glyph || 74 u_glyph > 0xFFFF || s_glyph > 0xFFFF) 75 continue; 76 77 glyphs[num_glyphs].set (u_glyph); 78 substitutes[num_glyphs].set (s_glyph); 79 80 num_glyphs++; 81 } 82 83 /* Bubble-sort! 84 * May not be good-enough for presidential candidate interviews, but good-enough for us... */ 85 hb_bubble_sort (&glyphs[0], num_glyphs, OT::GlyphID::cmp, &substitutes[0]); 86 87 OT::Supplier<OT::GlyphID> glyphs_supplier (glyphs, num_glyphs); 88 OT::Supplier<OT::GlyphID> substitutes_supplier (substitutes, num_glyphs); 89 90 /* Each glyph takes four bytes max, and there's some overhead. */ 91 char buf[(SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1) * 4 + 128]; 92 OT::hb_serialize_context_t c (buf, sizeof (buf)); 93 OT::SubstLookup *lookup = c.start_serialize<OT::SubstLookup> (); 94 bool ret = lookup->serialize_single (&c, 95 OT::LookupFlag::IgnoreMarks, 96 glyphs_supplier, 97 substitutes_supplier, 98 num_glyphs); 99 c.end_serialize (); 100 /* TODO sanitize the results? */ 101 102 return ret ? c.copy<OT::SubstLookup> () : NULL; 103 } 104 105 static OT::SubstLookup * 106 arabic_fallback_synthesize_lookup_ligature (const hb_ot_shape_plan_t *plan HB_UNUSED, 107 hb_font_t *font) 108 { 109 OT::GlyphID first_glyphs[ARRAY_LENGTH_CONST (ligature_table)]; 110 unsigned int first_glyphs_indirection[ARRAY_LENGTH_CONST (ligature_table)]; 111 unsigned int ligature_per_first_glyph_count_list[ARRAY_LENGTH_CONST (first_glyphs)]; 112 unsigned int num_first_glyphs = 0; 113 114 /* We know that all our ligatures are 2-component */ 115 OT::GlyphID ligature_list[ARRAY_LENGTH_CONST (first_glyphs) * ARRAY_LENGTH_CONST(ligature_table[0].ligatures)]; 116 unsigned int component_count_list[ARRAY_LENGTH_CONST (ligature_list)]; 117 OT::GlyphID component_list[ARRAY_LENGTH_CONST (ligature_list) * 1/* One extra component per ligature */]; 118 unsigned int num_ligatures = 0; 119 120 /* Populate arrays */ 121 122 /* Sort out the first-glyphs */ 123 for (unsigned int first_glyph_idx = 0; first_glyph_idx < ARRAY_LENGTH (first_glyphs); first_glyph_idx++) 124 { 125 hb_codepoint_t first_u = ligature_table[first_glyph_idx].first; 126 hb_codepoint_t first_glyph; 127 if (!hb_font_get_glyph (font, first_u, 0, &first_glyph)) 128 continue; 129 first_glyphs[num_first_glyphs].set (first_glyph); 130 ligature_per_first_glyph_count_list[num_first_glyphs] = 0; 131 first_glyphs_indirection[num_first_glyphs] = first_glyph_idx; 132 num_first_glyphs++; 133 } 134 hb_bubble_sort (&first_glyphs[0], num_first_glyphs, OT::GlyphID::cmp, &first_glyphs_indirection[0]); 135 136 /* Now that the first-glyphs are sorted, walk again, populate ligatures. */ 137 for (unsigned int i = 0; i < num_first_glyphs; i++) 138 { 139 unsigned int first_glyph_idx = first_glyphs_indirection[i]; 140 141 for (unsigned int second_glyph_idx = 0; second_glyph_idx < ARRAY_LENGTH (ligature_table[0].ligatures); second_glyph_idx++) 142 { 143 hb_codepoint_t second_u = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].second; 144 hb_codepoint_t ligature_u = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].ligature; 145 hb_codepoint_t second_glyph, ligature_glyph; 146 if (!second_u || 147 !hb_font_get_glyph (font, second_u, 0, &second_glyph) || 148 !hb_font_get_glyph (font, ligature_u, 0, &ligature_glyph)) 149 continue; 150 151 ligature_per_first_glyph_count_list[i]++; 152 153 ligature_list[num_ligatures].set (ligature_glyph); 154 component_count_list[num_ligatures] = 2; 155 component_list[num_ligatures].set (second_glyph); 156 num_ligatures++; 157 } 158 } 159 160 OT::Supplier<OT::GlyphID> first_glyphs_supplier (first_glyphs, num_first_glyphs); 161 OT::Supplier<unsigned int > ligature_per_first_glyph_count_supplier (ligature_per_first_glyph_count_list, num_first_glyphs); 162 OT::Supplier<OT::GlyphID> ligatures_supplier (ligature_list, num_ligatures); 163 OT::Supplier<unsigned int > component_count_supplier (component_count_list, num_ligatures); 164 OT::Supplier<OT::GlyphID> component_supplier (component_list, num_ligatures); 165 166 /* 16 bytes per ligature ought to be enough... */ 167 char buf[ARRAY_LENGTH_CONST (ligature_list) * 16 + 128]; 168 OT::hb_serialize_context_t c (buf, sizeof (buf)); 169 OT::SubstLookup *lookup = c.start_serialize<OT::SubstLookup> (); 170 bool ret = lookup->serialize_ligature (&c, 171 OT::LookupFlag::IgnoreMarks, 172 first_glyphs_supplier, 173 ligature_per_first_glyph_count_supplier, 174 num_first_glyphs, 175 ligatures_supplier, 176 component_count_supplier, 177 component_supplier); 178 179 c.end_serialize (); 180 /* TODO sanitize the results? */ 181 182 return ret ? c.copy<OT::SubstLookup> () : NULL; 183 } 184 185 static OT::SubstLookup * 186 arabic_fallback_synthesize_lookup (const hb_ot_shape_plan_t *plan, 187 hb_font_t *font, 188 unsigned int feature_index) 189 { 190 if (feature_index < 4) 191 return arabic_fallback_synthesize_lookup_single (plan, font, feature_index); 192 else 193 return arabic_fallback_synthesize_lookup_ligature (plan, font); 194 } 195 196 struct arabic_fallback_plan_t 197 { 198 ASSERT_POD (); 199 200 hb_mask_t mask_array[ARABIC_NUM_FALLBACK_FEATURES]; 201 OT::SubstLookup *lookup_array[ARABIC_NUM_FALLBACK_FEATURES]; 202 hb_set_digest_t digest_array[ARABIC_NUM_FALLBACK_FEATURES]; 203 }; 204 205 static const arabic_fallback_plan_t arabic_fallback_plan_nil = {}; 206 207 static arabic_fallback_plan_t * 208 arabic_fallback_plan_create (const hb_ot_shape_plan_t *plan, 209 hb_font_t *font) 210 { 211 arabic_fallback_plan_t *fallback_plan = (arabic_fallback_plan_t *) calloc (1, sizeof (arabic_fallback_plan_t)); 212 if (unlikely (!fallback_plan)) 213 return const_cast<arabic_fallback_plan_t *> (&arabic_fallback_plan_nil); 214 215 for (unsigned int i = 0; i < ARABIC_NUM_FALLBACK_FEATURES; i++) { 216 fallback_plan->mask_array[i] = plan->map.get_1_mask (arabic_fallback_features[i]); 217 if (fallback_plan->mask_array[i]) { 218 fallback_plan->lookup_array[i] = arabic_fallback_synthesize_lookup (plan, font, i); 219 if (fallback_plan->lookup_array[i]) 220 fallback_plan->lookup_array[i]->add_coverage (&fallback_plan->digest_array[i]); 221 } 222 } 223 224 return fallback_plan; 225 } 226 227 static void 228 arabic_fallback_plan_destroy (arabic_fallback_plan_t *fallback_plan) 229 { 230 if (!fallback_plan || fallback_plan == &arabic_fallback_plan_nil) 231 return; 232 233 for (unsigned int i = 0; i < ARABIC_NUM_FALLBACK_FEATURES; i++) 234 if (fallback_plan->lookup_array[i]) 235 free (fallback_plan->lookup_array[i]); 236 237 free (fallback_plan); 238 } 239 240 static void 241 arabic_fallback_plan_shape (arabic_fallback_plan_t *fallback_plan, 242 hb_font_t *font, 243 hb_buffer_t *buffer) 244 { 245 for (unsigned int i = 0; i < ARABIC_NUM_FALLBACK_FEATURES; i++) 246 if (fallback_plan->lookup_array[i]) { 247 OT::hb_apply_context_t c (0, font, buffer, fallback_plan->mask_array[i], true/*auto_zwj*/); 248 fallback_plan->lookup_array[i]->apply_string (&c, &fallback_plan->digest_array[i]); 249 } 250 } 251 252 253 #endif /* HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH */ 254
