1 /* 2 * Copyright © 2010 Red Hat, Inc. 3 * Copyright © 2012 Google, Inc. 4 * 5 * This is part of HarfBuzz, a text shaping library. 6 * 7 * Permission is hereby granted, without written agreement and without 8 * license or royalty fees, to use, copy, modify, and distribute this 9 * software and its documentation for any purpose, provided that the 10 * above copyright notice and the following two paragraphs appear in 11 * all copies of this software. 12 * 13 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR 14 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES 15 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN 16 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH 17 * DAMAGE. 18 * 19 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, 20 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 21 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS 22 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO 23 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. 24 * 25 * Red Hat Author(s): Behdad Esfahbod 26 * Google Author(s): Behdad Esfahbod 27 */ 28 29 #ifndef HB_OT_HEAD_TABLE_HH 30 #define HB_OT_HEAD_TABLE_HH 31 32 #include "hb-open-type.hh" 33 34 /* 35 * head -- Font Header 36 * https://docs.microsoft.com/en-us/typography/opentype/spec/head 37 */ 38 #define HB_OT_TAG_head HB_TAG('h','e','a','d') 39 40 41 namespace OT { 42 43 44 struct head 45 { 46 friend struct OpenTypeOffsetTable; 47 48 static constexpr hb_tag_t tableTag = HB_OT_TAG_head; 49 get_upemOT::head50 unsigned int get_upem () const 51 { 52 unsigned int upem = unitsPerEm; 53 /* If no valid head table found, assume 1000, which matches typical Type1 usage. */ 54 return 16 <= upem && upem <= 16384 ? upem : 1000; 55 } 56 serializeOT::head57 bool serialize (hb_serialize_context_t *c) const 58 { 59 TRACE_SERIALIZE (this); 60 return_trace ((bool) c->embed (this)); 61 } 62 subsetOT::head63 bool subset (hb_subset_context_t *c) const 64 { 65 TRACE_SUBSET (this); 66 return_trace (serialize (c->serializer)); 67 } 68 69 enum mac_style_flag_t { 70 BOLD = 1u<<0, 71 ITALIC = 1u<<1, 72 UNDERLINE = 1u<<2, 73 OUTLINE = 1u<<3, 74 SHADOW = 1u<<4, 75 CONDENSED = 1u<<5, 76 EXPANDED = 1u<<6, 77 }; 78 is_boldOT::head79 bool is_bold () const { return macStyle & BOLD; } is_italicOT::head80 bool is_italic () const { return macStyle & ITALIC; } is_condensedOT::head81 bool is_condensed () const { return macStyle & CONDENSED; } is_expandedOT::head82 bool is_expanded () const { return macStyle & EXPANDED; } 83 sanitizeOT::head84 bool sanitize (hb_sanitize_context_t *c) const 85 { 86 TRACE_SANITIZE (this); 87 return_trace (c->check_struct (this) && 88 version.major == 1 && 89 magicNumber == 0x5F0F3CF5u); 90 } 91 92 protected: 93 FixedVersion<>version; /* Version of the head table--currently 94 * 0x00010000u for version 1.0. */ 95 FixedVersion<>fontRevision; /* Set by font manufacturer. */ 96 HBUINT32 checkSumAdjustment; /* To compute: set it to 0, sum the 97 * entire font as HBUINT32, then store 98 * 0xB1B0AFBAu - sum. */ 99 HBUINT32 magicNumber; /* Set to 0x5F0F3CF5u. */ 100 HBUINT16 flags; /* Bit 0: Baseline for font at y=0; 101 * Bit 1: Left sidebearing point at x=0; 102 * Bit 2: Instructions may depend on point size; 103 * Bit 3: Force ppem to integer values for all 104 * internal scaler math; may use fractional 105 * ppem sizes if this bit is clear; 106 * Bit 4: Instructions may alter advance width 107 * (the advance widths might not scale linearly); 108 * Bits 5-10: These should be set according to 109 * Apple's specification. However, they are not 110 * implemented in OpenType. 111 * Bit 5: This bit should be set in fonts that are 112 * intended to e laid out vertically, and in 113 * which the glyphs have been drawn such that an 114 * x-coordinate of 0 corresponds to the desired 115 * vertical baseline. 116 * Bit 6: This bit must be set to zero. 117 * Bit 7: This bit should be set if the font 118 * requires layout for correct linguistic 119 * rendering (e.g. Arabic fonts). 120 * Bit 8: This bit should be set for a GX font 121 * which has one or more metamorphosis effects 122 * designated as happening by default. 123 * Bit 9: This bit should be set if the font 124 * contains any strong right-to-left glyphs. 125 * Bit 10: This bit should be set if the font 126 * contains Indic-style rearrangement effects. 127 * Bit 11: Font data is 'lossless,' as a result 128 * of having been compressed and decompressed 129 * with the Agfa MicroType Express engine. 130 * Bit 12: Font converted (produce compatible metrics) 131 * Bit 13: Font optimized for ClearType™. 132 * Note, fonts that rely on embedded bitmaps (EBDT) 133 * for rendering should not be considered optimized 134 * for ClearType, and therefore should keep this bit 135 * cleared. 136 * Bit 14: Last Resort font. If set, indicates that 137 * the glyphs encoded in the cmap subtables are simply 138 * generic symbolic representations of code point 139 * ranges and don’t truly represent support for those 140 * code points. If unset, indicates that the glyphs 141 * encoded in the cmap subtables represent proper 142 * support for those code points. 143 * Bit 15: Reserved, set to 0. */ 144 HBUINT16 unitsPerEm; /* Valid range is from 16 to 16384. This value 145 * should be a power of 2 for fonts that have 146 * TrueType outlines. */ 147 LONGDATETIME created; /* Number of seconds since 12:00 midnight, 148 January 1, 1904. 64-bit integer */ 149 LONGDATETIME modified; /* Number of seconds since 12:00 midnight, 150 January 1, 1904. 64-bit integer */ 151 HBINT16 xMin; /* For all glyph bounding boxes. */ 152 HBINT16 yMin; /* For all glyph bounding boxes. */ 153 HBINT16 xMax; /* For all glyph bounding boxes. */ 154 HBINT16 yMax; /* For all glyph bounding boxes. */ 155 HBUINT16 macStyle; /* Bit 0: Bold (if set to 1); 156 * Bit 1: Italic (if set to 1) 157 * Bit 2: Underline (if set to 1) 158 * Bit 3: Outline (if set to 1) 159 * Bit 4: Shadow (if set to 1) 160 * Bit 5: Condensed (if set to 1) 161 * Bit 6: Extended (if set to 1) 162 * Bits 7-15: Reserved (set to 0). */ 163 HBUINT16 lowestRecPPEM; /* Smallest readable size in pixels. */ 164 HBINT16 fontDirectionHint; /* Deprecated (Set to 2). 165 * 0: Fully mixed directional glyphs; 166 * 1: Only strongly left to right; 167 * 2: Like 1 but also contains neutrals; 168 * -1: Only strongly right to left; 169 * -2: Like -1 but also contains neutrals. */ 170 public: 171 HBUINT16 indexToLocFormat; /* 0 for short offsets, 1 for long. */ 172 HBUINT16 glyphDataFormat; /* 0 for current format. */ 173 174 DEFINE_SIZE_STATIC (54); 175 }; 176 177 178 } /* namespace OT */ 179 180 181 #endif /* HB_OT_HEAD_TABLE_HH */ 182