1 #ifndef OT_LAYOUT_GSUB_ALTERNATESET_HH 2 #define OT_LAYOUT_GSUB_ALTERNATESET_HH 3 4 #include "Common.hh" 5 6 namespace OT { 7 namespace Layout { 8 namespace GSUB_impl { 9 10 template <typename Types> 11 struct AlternateSet 12 { 13 protected: 14 Array16Of<typename Types::HBGlyphID> 15 alternates; /* Array of alternate GlyphIDs--in 16 * arbitrary order */ 17 public: 18 DEFINE_SIZE_ARRAY (2, alternates); 19 sanitizeOT::Layout::GSUB_impl::AlternateSet20 bool sanitize (hb_sanitize_context_t *c) const 21 { 22 TRACE_SANITIZE (this); 23 return_trace (alternates.sanitize (c)); 24 } 25 intersectsOT::Layout::GSUB_impl::AlternateSet26 bool intersects (const hb_set_t *glyphs) const 27 { return hb_any (alternates, glyphs); } 28 closureOT::Layout::GSUB_impl::AlternateSet29 void closure (hb_closure_context_t *c) const 30 { c->output->add_array (alternates.arrayZ, alternates.len); } 31 collect_glyphsOT::Layout::GSUB_impl::AlternateSet32 void collect_glyphs (hb_collect_glyphs_context_t *c) const 33 { c->output->add_array (alternates.arrayZ, alternates.len); } 34 applyOT::Layout::GSUB_impl::AlternateSet35 bool apply (hb_ot_apply_context_t *c) const 36 { 37 TRACE_APPLY (this); 38 unsigned int count = alternates.len; 39 40 if (unlikely (!count)) return_trace (false); 41 42 hb_mask_t glyph_mask = c->buffer->cur().mask; 43 hb_mask_t lookup_mask = c->lookup_mask; 44 45 /* Note: This breaks badly if two features enabled this lookup together. */ 46 unsigned int shift = hb_ctz (lookup_mask); 47 unsigned int alt_index = ((lookup_mask & glyph_mask) >> shift); 48 49 /* If alt_index is MAX_VALUE, randomize feature if it is the rand feature. */ 50 if (alt_index == HB_OT_MAP_MAX_VALUE && c->random) 51 { 52 /* Maybe we can do better than unsafe-to-break all; but since we are 53 * changing random state, it would be hard to track that. Good 'nough. */ 54 c->buffer->unsafe_to_break (0, c->buffer->len); 55 alt_index = c->random_number () % count + 1; 56 } 57 58 if (unlikely (alt_index > count || alt_index == 0)) return_trace (false); 59 60 if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ()) 61 { 62 c->buffer->sync_so_far (); 63 c->buffer->message (c->font, 64 "replacing glyph at %u (alternate substitution)", 65 c->buffer->idx); 66 } 67 68 c->replace_glyph (alternates[alt_index - 1]); 69 70 if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ()) 71 { 72 c->buffer->message (c->font, 73 "replaced glyph at %u (alternate substitution)", 74 c->buffer->idx - 1u); 75 } 76 77 return_trace (true); 78 } 79 80 unsigned get_alternatesOT::Layout::GSUB_impl::AlternateSet81 get_alternates (unsigned start_offset, 82 unsigned *alternate_count /* IN/OUT. May be NULL. */, 83 hb_codepoint_t *alternate_glyphs /* OUT. May be NULL. */) const 84 { 85 if (alternates.len && alternate_count) 86 { 87 + alternates.as_array ().sub_array (start_offset, alternate_count) 88 | hb_sink (hb_array (alternate_glyphs, *alternate_count)) 89 ; 90 } 91 return alternates.len; 92 } 93 94 template <typename Iterator, 95 hb_requires (hb_is_source_of (Iterator, hb_codepoint_t))> serializeOT::Layout::GSUB_impl::AlternateSet96 bool serialize (hb_serialize_context_t *c, 97 Iterator alts) 98 { 99 TRACE_SERIALIZE (this); 100 return_trace (alternates.serialize (c, alts)); 101 } 102 subsetOT::Layout::GSUB_impl::AlternateSet103 bool subset (hb_subset_context_t *c) const 104 { 105 TRACE_SUBSET (this); 106 const hb_set_t &glyphset = *c->plan->glyphset_gsub (); 107 const hb_map_t &glyph_map = *c->plan->glyph_map; 108 109 auto it = 110 + hb_iter (alternates) 111 | hb_filter (glyphset) 112 | hb_map (glyph_map) 113 ; 114 115 auto *out = c->serializer->start_embed (*this); 116 return_trace (out->serialize (c->serializer, it) && 117 out->alternates); 118 } 119 }; 120 121 } 122 } 123 } 124 125 126 #endif /* OT_LAYOUT_GSUB_ALTERNATESET_HH */ 127