hb-ot-hdmx-table.hh (5137B)
1 /* 2 * Copyright © 2018 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): Garret Rieger 25 */ 26 27 #ifndef HB_OT_HDMX_TABLE_HH 28 #define HB_OT_HDMX_TABLE_HH 29 30 #include "hb-open-type.hh" 31 32 /* 33 * hdmx -- Horizontal Device Metrics 34 * https://docs.microsoft.com/en-us/typography/opentype/spec/hdmx 35 */ 36 #define HB_OT_TAG_hdmx HB_TAG('h','d','m','x') 37 38 39 namespace OT { 40 41 42 struct DeviceRecord 43 { 44 static unsigned int get_size (unsigned count) 45 { return hb_ceil_to_4 (min_size + count * HBUINT8::static_size); } 46 47 template<typename Iterator, 48 hb_requires (hb_is_iterator (Iterator))> 49 bool serialize (hb_serialize_context_t *c, 50 unsigned pixelSize, 51 Iterator it, 52 const hb_vector_t<hb_codepoint_pair_t> new_to_old_gid_list, 53 unsigned num_glyphs) 54 { 55 TRACE_SERIALIZE (this); 56 57 if (unlikely (!c->extend (this, num_glyphs))) return_trace (false); 58 59 this->pixelSize = pixelSize; 60 this->maxWidth = 61 + it 62 | hb_reduce (hb_max, 0u); 63 64 for (auto &_ : new_to_old_gid_list) 65 widthsZ[_.first] = *it++; 66 67 return_trace (true); 68 } 69 70 bool sanitize (hb_sanitize_context_t *c, unsigned sizeDeviceRecord) const 71 { 72 TRACE_SANITIZE (this); 73 return_trace (likely (c->check_struct (this) && 74 hb_barrier () && 75 c->check_range (this, sizeDeviceRecord))); 76 } 77 78 HBUINT8 pixelSize; /* Pixel size for following widths (as ppem). */ 79 HBUINT8 maxWidth; /* Maximum width. */ 80 UnsizedArrayOf<HBUINT8> widthsZ; /* Array of widths (numGlyphs is from the 'maxp' table). */ 81 public: 82 DEFINE_SIZE_UNBOUNDED (2); 83 }; 84 85 86 struct hdmx 87 { 88 static constexpr hb_tag_t tableTag = HB_OT_TAG_hdmx; 89 90 unsigned int get_size () const 91 { return min_size + numRecords * sizeDeviceRecord; } 92 93 template<typename Iterator, 94 hb_requires (hb_is_iterator (Iterator))> 95 bool serialize (hb_serialize_context_t *c, 96 unsigned version, 97 Iterator it, 98 hb_array_t<const hb_codepoint_pair_t> new_to_old_gid_list, 99 unsigned num_glyphs) 100 { 101 TRACE_SERIALIZE (this); 102 103 if (unlikely (!c->extend_min ((*this)))) return_trace (false); 104 105 this->version = version; 106 this->numRecords = it.len (); 107 this->sizeDeviceRecord = DeviceRecord::get_size (num_glyphs); 108 109 for (const hb_item_type<Iterator>& _ : +it) 110 c->start_embed<DeviceRecord> ()->serialize (c, _.first, _.second, new_to_old_gid_list, num_glyphs); 111 112 return_trace (c->successful ()); 113 } 114 115 116 bool subset (hb_subset_context_t *c) const 117 { 118 TRACE_SUBSET (this); 119 120 auto *hdmx_prime = c->serializer->start_embed <hdmx> (); 121 122 unsigned num_input_glyphs = get_num_glyphs (); 123 auto it = 124 + hb_range ((unsigned) numRecords) 125 | hb_map ([c, num_input_glyphs, this] (unsigned _) 126 { 127 const DeviceRecord *device_record = 128 &StructAtOffset<DeviceRecord> (&firstDeviceRecord, 129 _ * sizeDeviceRecord); 130 auto row = 131 + hb_iter (c->plan->new_to_old_gid_list) 132 | hb_map ([num_input_glyphs, device_record] (hb_codepoint_pair_t _) 133 { 134 return device_record->widthsZ.as_array (num_input_glyphs) [_.second]; 135 }) 136 ; 137 return hb_pair ((unsigned) device_record->pixelSize, +row); 138 }) 139 ; 140 141 hdmx_prime->serialize (c->serializer, version, it, 142 c->plan->new_to_old_gid_list, 143 c->plan->num_output_glyphs ()); 144 return_trace (true); 145 } 146 147 unsigned get_num_glyphs () const 148 { 149 return sizeDeviceRecord - DeviceRecord::min_size; 150 } 151 152 bool sanitize (hb_sanitize_context_t *c) const 153 { 154 TRACE_SANITIZE (this); 155 return_trace (c->check_struct (this) && 156 hb_barrier () && 157 !hb_unsigned_mul_overflows (numRecords, sizeDeviceRecord) && 158 min_size + numRecords * sizeDeviceRecord > numRecords * sizeDeviceRecord && 159 sizeDeviceRecord >= DeviceRecord::min_size && 160 c->check_range (this, get_size ())); 161 } 162 163 protected: 164 HBUINT16 version; /* Table version number (0) */ 165 HBUINT16 numRecords; /* Number of device records. */ 166 HBUINT32 sizeDeviceRecord; 167 /* Size of a device record, 32-bit aligned. */ 168 DeviceRecord firstDeviceRecord; 169 /* Array of device records. */ 170 public: 171 DEFINE_SIZE_MIN (8); 172 }; 173 174 } /* namespace OT */ 175 176 177 #endif /* HB_OT_HDMX_TABLE_HH */