1 /* 2 * Copyright © 2017 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_VAR_AVAR_TABLE_HH 28 #define HB_OT_VAR_AVAR_TABLE_HH 29 30 #include "hb-open-type.hh" 31 32 /* 33 * avar -- Axis Variations 34 * https://docs.microsoft.com/en-us/typography/opentype/spec/avar 35 */ 36 37 #define HB_OT_TAG_avar HB_TAG('a','v','a','r') 38 39 40 namespace OT { 41 42 43 struct AxisValueMap 44 { sanitizeOT::AxisValueMap45 bool sanitize (hb_sanitize_context_t *c) const 46 { 47 TRACE_SANITIZE (this); 48 return_trace (c->check_struct (this)); 49 } 50 51 public: 52 F2DOT14 coords[2]; 53 // F2DOT14 fromCoord; /* A normalized coordinate value obtained using 54 // * default normalization. */ 55 // F2DOT14 toCoord; /* The modified, normalized coordinate value. */ 56 57 public: 58 DEFINE_SIZE_STATIC (4); 59 }; 60 61 struct SegmentMaps : ArrayOf<AxisValueMap> 62 { mapOT::SegmentMaps63 int map (int value, unsigned int from_offset = 0, unsigned int to_offset = 1) const 64 { 65 #define fromCoord coords[from_offset] 66 #define toCoord coords[to_offset] 67 /* The following special-cases are not part of OpenType, which requires 68 * that at least -1, 0, and +1 must be mapped. But we include these as 69 * part of a better error recovery scheme. */ 70 if (len < 2) 71 { 72 if (!len) 73 return value; 74 else /* len == 1*/ 75 return value - arrayZ[0].fromCoord + arrayZ[0].toCoord; 76 } 77 78 if (value <= arrayZ[0].fromCoord) 79 return value - arrayZ[0].fromCoord + arrayZ[0].toCoord; 80 81 unsigned int i; 82 unsigned int count = len; 83 for (i = 1; i < count && value > arrayZ[i].fromCoord; i++) 84 ; 85 86 if (value >= arrayZ[i].fromCoord) 87 return value - arrayZ[i].fromCoord + arrayZ[i].toCoord; 88 89 if (unlikely (arrayZ[i-1].fromCoord == arrayZ[i].fromCoord)) 90 return arrayZ[i-1].toCoord; 91 92 int denom = arrayZ[i].fromCoord - arrayZ[i-1].fromCoord; 93 return arrayZ[i-1].toCoord + 94 ((arrayZ[i].toCoord - arrayZ[i-1].toCoord) * 95 (value - arrayZ[i-1].fromCoord) + denom/2) / denom; 96 #undef toCoord 97 #undef fromCoord 98 } 99 unmapOT::SegmentMaps100 int unmap (int value) const { return map (value, 1, 0); } 101 102 public: 103 DEFINE_SIZE_ARRAY (2, *this); 104 }; 105 106 struct avar 107 { 108 static constexpr hb_tag_t tableTag = HB_OT_TAG_avar; 109 sanitizeOT::avar110 bool sanitize (hb_sanitize_context_t *c) const 111 { 112 TRACE_SANITIZE (this); 113 if (unlikely (!(version.sanitize (c) && 114 version.major == 1 && 115 c->check_struct (this)))) 116 return_trace (false); 117 118 const SegmentMaps *map = &firstAxisSegmentMaps; 119 unsigned int count = axisCount; 120 for (unsigned int i = 0; i < count; i++) 121 { 122 if (unlikely (!map->sanitize (c))) 123 return_trace (false); 124 map = &StructAfter<SegmentMaps> (*map); 125 } 126 127 return_trace (true); 128 } 129 map_coordsOT::avar130 void map_coords (int *coords, unsigned int coords_length) const 131 { 132 unsigned int count = hb_min (coords_length, axisCount); 133 134 const SegmentMaps *map = &firstAxisSegmentMaps; 135 for (unsigned int i = 0; i < count; i++) 136 { 137 coords[i] = map->map (coords[i]); 138 map = &StructAfter<SegmentMaps> (*map); 139 } 140 } 141 unmap_coordsOT::avar142 void unmap_coords (int *coords, unsigned int coords_length) const 143 { 144 unsigned int count = hb_min (coords_length, axisCount); 145 146 const SegmentMaps *map = &firstAxisSegmentMaps; 147 for (unsigned int i = 0; i < count; i++) 148 { 149 coords[i] = map->unmap (coords[i]); 150 map = &StructAfter<SegmentMaps> (*map); 151 } 152 } 153 154 protected: 155 FixedVersion<>version; /* Version of the avar table 156 * initially set to 0x00010000u */ 157 HBUINT16 reserved; /* This field is permanently reserved. Set to 0. */ 158 HBUINT16 axisCount; /* The number of variation axes in the font. This 159 * must be the same number as axisCount in the 160 * 'fvar' table. */ 161 SegmentMaps firstAxisSegmentMaps; 162 163 public: 164 DEFINE_SIZE_MIN (8); 165 }; 166 167 } /* namespace OT */ 168 169 170 #endif /* HB_OT_VAR_AVAR_TABLE_HH */ 171