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 : Array16Of<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 - 1; 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 roundf (arrayZ[i-1].toCoord + ((float) (arrayZ[i].toCoord - arrayZ[i-1].toCoord) * 94 (value - arrayZ[i-1].fromCoord)) / denom); 95 #undef toCoord 96 #undef fromCoord 97 } 98 unmapOT::SegmentMaps99 int unmap (int value) const { return map (value, 1, 0); } 100 101 public: 102 DEFINE_SIZE_ARRAY (2, *this); 103 }; 104 105 struct avar 106 { 107 static constexpr hb_tag_t tableTag = HB_OT_TAG_avar; 108 sanitizeOT::avar109 bool sanitize (hb_sanitize_context_t *c) const 110 { 111 TRACE_SANITIZE (this); 112 if (unlikely (!(version.sanitize (c) && 113 version.major == 1 && 114 c->check_struct (this)))) 115 return_trace (false); 116 117 const SegmentMaps *map = &firstAxisSegmentMaps; 118 unsigned int count = axisCount; 119 for (unsigned int i = 0; i < count; i++) 120 { 121 if (unlikely (!map->sanitize (c))) 122 return_trace (false); 123 map = &StructAfter<SegmentMaps> (*map); 124 } 125 126 return_trace (true); 127 } 128 map_coordsOT::avar129 void map_coords (int *coords, unsigned int coords_length) const 130 { 131 unsigned int count = hb_min (coords_length, axisCount); 132 133 const SegmentMaps *map = &firstAxisSegmentMaps; 134 for (unsigned int i = 0; i < count; i++) 135 { 136 coords[i] = map->map (coords[i]); 137 map = &StructAfter<SegmentMaps> (*map); 138 } 139 } 140 unmap_coordsOT::avar141 void unmap_coords (int *coords, unsigned int coords_length) const 142 { 143 unsigned int count = hb_min (coords_length, axisCount); 144 145 const SegmentMaps *map = &firstAxisSegmentMaps; 146 for (unsigned int i = 0; i < count; i++) 147 { 148 coords[i] = map->unmap (coords[i]); 149 map = &StructAfter<SegmentMaps> (*map); 150 } 151 } 152 153 protected: 154 FixedVersion<>version; /* Version of the avar table 155 * initially set to 0x00010000u */ 156 HBUINT16 reserved; /* This field is permanently reserved. Set to 0. */ 157 HBUINT16 axisCount; /* The number of variation axes in the font. This 158 * must be the same number as axisCount in the 159 * 'fvar' table. */ 160 SegmentMaps firstAxisSegmentMaps; 161 162 public: 163 DEFINE_SIZE_MIN (8); 164 }; 165 166 } /* namespace OT */ 167 168 169 #endif /* HB_OT_VAR_AVAR_TABLE_HH */ 170