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 fromCoord; /* A normalized coordinate value obtained using 53 * default normalization. */ 54 F2DOT14 toCoord; /* The modified, normalized coordinate value. */ 55 56 public: 57 DEFINE_SIZE_STATIC (4); 58 }; 59 60 struct SegmentMaps : ArrayOf<AxisValueMap> 61 { mapOT::SegmentMaps62 int map (int value) const 63 { 64 /* The following special-cases are not part of OpenType, which requires 65 * that at least -1, 0, and +1 must be mapped. But we include these as 66 * part of a better error recovery scheme. */ 67 68 if (len < 2) 69 { 70 if (!len) 71 return value; 72 else /* len == 1*/ 73 return value - arrayZ[0].fromCoord + arrayZ[0].toCoord; 74 } 75 76 if (value <= arrayZ[0].fromCoord) 77 return value - arrayZ[0].fromCoord + arrayZ[0].toCoord; 78 79 unsigned int i; 80 unsigned int count = len; 81 for (i = 1; i < count && value > arrayZ[i].fromCoord; i++) 82 ; 83 84 if (value >= arrayZ[i].fromCoord) 85 return value - arrayZ[i].fromCoord + arrayZ[i].toCoord; 86 87 if (unlikely (arrayZ[i-1].fromCoord == arrayZ[i].fromCoord)) 88 return arrayZ[i-1].toCoord; 89 90 int denom = arrayZ[i].fromCoord - arrayZ[i-1].fromCoord; 91 return arrayZ[i-1].toCoord + 92 ((arrayZ[i].toCoord - arrayZ[i-1].toCoord) * 93 (value - arrayZ[i-1].fromCoord) + denom/2) / denom; 94 } 95 96 public: 97 DEFINE_SIZE_ARRAY (2, *this); 98 }; 99 100 struct avar 101 { 102 enum { tableTag = HB_OT_TAG_avar }; 103 sanitizeOT::avar104 bool sanitize (hb_sanitize_context_t *c) const 105 { 106 TRACE_SANITIZE (this); 107 if (unlikely (!(version.sanitize (c) && 108 version.major == 1 && 109 c->check_struct (this)))) 110 return_trace (false); 111 112 const SegmentMaps *map = &firstAxisSegmentMaps; 113 unsigned int count = axisCount; 114 for (unsigned int i = 0; i < count; i++) 115 { 116 if (unlikely (!map->sanitize (c))) 117 return_trace (false); 118 map = &StructAfter<SegmentMaps> (*map); 119 } 120 121 return_trace (true); 122 } 123 map_coordsOT::avar124 void map_coords (int *coords, unsigned int coords_length) const 125 { 126 unsigned int count = MIN<unsigned int> (coords_length, axisCount); 127 128 const SegmentMaps *map = &firstAxisSegmentMaps; 129 for (unsigned int i = 0; i < count; i++) 130 { 131 coords[i] = map->map (coords[i]); 132 map = &StructAfter<SegmentMaps> (*map); 133 } 134 } 135 136 protected: 137 FixedVersion<>version; /* Version of the avar table 138 * initially set to 0x00010000u */ 139 HBUINT16 reserved; /* This field is permanently reserved. Set to 0. */ 140 HBUINT16 axisCount; /* The number of variation axes in the font. This 141 * must be the same number as axisCount in the 142 * 'fvar' table. */ 143 SegmentMaps firstAxisSegmentMaps; 144 145 public: 146 DEFINE_SIZE_MIN (8); 147 }; 148 149 } /* namespace OT */ 150 151 152 #endif /* HB_OT_VAR_AVAR_TABLE_HH */ 153