hb-aat-layout-bsln-table.hh (4636B)
1 /* 2 * Copyright © 2018 Ebrahim Byagowi 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 25 #ifndef HB_AAT_LAYOUT_BSLN_TABLE_HH 26 #define HB_AAT_LAYOUT_BSLN_TABLE_HH 27 28 #include "hb-aat-layout-common.hh" 29 30 /* 31 * bsln -- Baseline 32 * https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6bsln.html 33 */ 34 #define HB_AAT_TAG_bsln HB_TAG('b','s','l','n') 35 36 37 namespace AAT { 38 39 40 struct BaselineTableFormat0Part 41 { 42 bool sanitize (hb_sanitize_context_t *c) const 43 { 44 TRACE_SANITIZE (this); 45 return_trace (c->check_struct (this)); 46 } 47 48 protected: 49 // Roman, Ideographic centered, Ideographic low, Hanging and Math 50 // are the default defined ones, but any other maybe accessed also. 51 HBINT16 deltas[32]; /* These are the FUnit distance deltas from 52 * the font's natural baseline to the other 53 * baselines used in the font. */ 54 public: 55 DEFINE_SIZE_STATIC (64); 56 }; 57 58 struct BaselineTableFormat1Part 59 { 60 bool sanitize (hb_sanitize_context_t *c) const 61 { 62 TRACE_SANITIZE (this); 63 return_trace (likely (c->check_struct (this) && 64 lookupTable.sanitize (c))); 65 } 66 67 protected: 68 HBINT16 deltas[32]; /* ditto */ 69 Lookup<HBUINT16> 70 lookupTable; /* Lookup table that maps glyphs to their 71 * baseline values. */ 72 public: 73 DEFINE_SIZE_MIN (66); 74 }; 75 76 struct BaselineTableFormat2Part 77 { 78 bool sanitize (hb_sanitize_context_t *c) const 79 { 80 TRACE_SANITIZE (this); 81 return_trace (c->check_struct (this)); 82 } 83 84 protected: 85 HBGlyphID16 stdGlyph; /* The specific glyph index number in this 86 * font that is used to set the baseline values. 87 * This is the standard glyph. 88 * This glyph must contain a set of control points 89 * (whose numbers are contained in the ctlPoints field) 90 * that are used to determine baseline distances. */ 91 HBUINT16 ctlPoints[32]; /* Set of control point numbers, 92 * associated with the standard glyph. 93 * A value of 0xFFFF means there is no corresponding 94 * control point in the standard glyph. */ 95 public: 96 DEFINE_SIZE_STATIC (66); 97 }; 98 99 struct BaselineTableFormat3Part 100 { 101 bool sanitize (hb_sanitize_context_t *c) const 102 { 103 TRACE_SANITIZE (this); 104 return_trace (likely (c->check_struct (this) && lookupTable.sanitize (c))); 105 } 106 107 protected: 108 HBGlyphID16 stdGlyph; /* ditto */ 109 HBUINT16 ctlPoints[32]; /* ditto */ 110 Lookup<HBUINT16> 111 lookupTable; /* Lookup table that maps glyphs to their 112 * baseline values. */ 113 public: 114 DEFINE_SIZE_MIN (68); 115 }; 116 117 struct bsln 118 { 119 static constexpr hb_tag_t tableTag = HB_AAT_TAG_bsln; 120 121 bool sanitize (hb_sanitize_context_t *c) const 122 { 123 TRACE_SANITIZE (this); 124 if (unlikely (!(c->check_struct (this) && defaultBaseline < 32))) 125 return_trace (false); 126 hb_barrier (); 127 128 switch (format) 129 { 130 case 0: return_trace (parts.format0.sanitize (c)); 131 case 1: return_trace (parts.format1.sanitize (c)); 132 case 2: return_trace (parts.format2.sanitize (c)); 133 case 3: return_trace (parts.format3.sanitize (c)); 134 default:return_trace (true); 135 } 136 } 137 138 protected: 139 FixedVersion<>version; /* Version number of the Baseline table. */ 140 HBUINT16 format; /* Format of the baseline table. Only one baseline 141 * format may be selected for the font. */ 142 HBUINT16 defaultBaseline;/* Default baseline value for all glyphs. 143 * This value can be from 0 through 31. */ 144 union { 145 // Distance-Based Formats 146 BaselineTableFormat0Part format0; 147 BaselineTableFormat1Part format1; 148 // Control Point-based Formats 149 BaselineTableFormat2Part format2; 150 BaselineTableFormat3Part format3; 151 } parts; 152 public: 153 DEFINE_SIZE_MIN (8); 154 }; 155 156 } /* namespace AAT */ 157 158 159 #endif /* HB_AAT_LAYOUT_BSLN_TABLE_HH */