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 head *out = c->serializer->embed (this); 67 if (unlikely (!out)) return_trace (false); 68 69 if (c->plan->normalized_coords) 70 { 71 if (unlikely (!c->serializer->check_assign (out->xMin, c->plan->head_maxp_info.xMin, 72 HB_SERIALIZE_ERROR_INT_OVERFLOW))) 73 return_trace (false); 74 if (unlikely (!c->serializer->check_assign (out->xMax, c->plan->head_maxp_info.xMax, 75 HB_SERIALIZE_ERROR_INT_OVERFLOW))) 76 return_trace (false); 77 if (unlikely (!c->serializer->check_assign (out->yMin, c->plan->head_maxp_info.yMin, 78 HB_SERIALIZE_ERROR_INT_OVERFLOW))) 79 return_trace (false); 80 if (unlikely (!c->serializer->check_assign (out->yMax, c->plan->head_maxp_info.yMax, 81 HB_SERIALIZE_ERROR_INT_OVERFLOW))) 82 return_trace (false); 83 } 84 return_trace (true); 85 } 86 87 enum mac_style_flag_t { 88 BOLD = 1u<<0, 89 ITALIC = 1u<<1, 90 UNDERLINE = 1u<<2, 91 OUTLINE = 1u<<3, 92 SHADOW = 1u<<4, 93 CONDENSED = 1u<<5, 94 EXPANDED = 1u<<6, 95 }; 96 is_boldOT::head97 bool is_bold () const { return macStyle & BOLD; } is_italicOT::head98 bool is_italic () const { return macStyle & ITALIC; } is_condensedOT::head99 bool is_condensed () const { return macStyle & CONDENSED; } is_expandedOT::head100 bool is_expanded () const { return macStyle & EXPANDED; } 101 sanitizeOT::head102 bool sanitize (hb_sanitize_context_t *c) const 103 { 104 TRACE_SANITIZE (this); 105 return_trace (c->check_struct (this) && 106 hb_barrier () && 107 version.major == 1 && 108 magicNumber == 0x5F0F3CF5u); 109 } 110 111 protected: 112 FixedVersion<>version; /* Version of the head table--currently 113 * 0x00010000u for version 1.0. */ 114 FixedVersion<>fontRevision; /* Set by font manufacturer. */ 115 HBUINT32 checkSumAdjustment; /* To compute: set it to 0, sum the 116 * entire font as HBUINT32, then store 117 * 0xB1B0AFBAu - sum. */ 118 HBUINT32 magicNumber; /* Set to 0x5F0F3CF5u. */ 119 public: 120 HBUINT16 flags; /* Bit 0: Baseline for font at y=0; 121 * Bit 1: Left sidebearing point at x=0; 122 * Bit 2: Instructions may depend on point size; 123 * Bit 3: Force ppem to integer values for all 124 * internal scaler math; may use fractional 125 * ppem sizes if this bit is clear; 126 * Bit 4: Instructions may alter advance width 127 * (the advance widths might not scale linearly); 128 * Bits 5-10: These should be set according to 129 * Apple's specification. However, they are not 130 * implemented in OpenType. 131 * Bit 5: This bit should be set in fonts that are 132 * intended to e laid out vertically, and in 133 * which the glyphs have been drawn such that an 134 * x-coordinate of 0 corresponds to the desired 135 * vertical baseline. 136 * Bit 6: This bit must be set to zero. 137 * Bit 7: This bit should be set if the font 138 * requires layout for correct linguistic 139 * rendering (e.g. Arabic fonts). 140 * Bit 8: This bit should be set for a GX font 141 * which has one or more metamorphosis effects 142 * designated as happening by default. 143 * Bit 9: This bit should be set if the font 144 * contains any strong right-to-left glyphs. 145 * Bit 10: This bit should be set if the font 146 * contains Indic-style rearrangement effects. 147 * Bit 11: Font data is 'lossless,' as a result 148 * of having been compressed and decompressed 149 * with the Agfa MicroType Express engine. 150 * Bit 12: Font converted (produce compatible metrics) 151 * Bit 13: Font optimized for ClearType™. 152 * Note, fonts that rely on embedded bitmaps (EBDT) 153 * for rendering should not be considered optimized 154 * for ClearType, and therefore should keep this bit 155 * cleared. 156 * Bit 14: Last Resort font. If set, indicates that 157 * the glyphs encoded in the cmap subtables are simply 158 * generic symbolic representations of code point 159 * ranges and don’t truly represent support for those 160 * code points. If unset, indicates that the glyphs 161 * encoded in the cmap subtables represent proper 162 * support for those code points. 163 * Bit 15: Reserved, set to 0. */ 164 protected: 165 HBUINT16 unitsPerEm; /* Valid range is from 16 to 16384. This value 166 * should be a power of 2 for fonts that have 167 * TrueType outlines. */ 168 LONGDATETIME created; /* Number of seconds since 12:00 midnight, 169 January 1, 1904. 64-bit integer */ 170 LONGDATETIME modified; /* Number of seconds since 12:00 midnight, 171 January 1, 1904. 64-bit integer */ 172 public: 173 HBINT16 xMin; /* For all glyph bounding boxes. */ 174 HBINT16 yMin; /* For all glyph bounding boxes. */ 175 HBINT16 xMax; /* For all glyph bounding boxes. */ 176 HBINT16 yMax; /* For all glyph bounding boxes. */ 177 protected: 178 HBUINT16 macStyle; /* Bit 0: Bold (if set to 1); 179 * Bit 1: Italic (if set to 1) 180 * Bit 2: Underline (if set to 1) 181 * Bit 3: Outline (if set to 1) 182 * Bit 4: Shadow (if set to 1) 183 * Bit 5: Condensed (if set to 1) 184 * Bit 6: Extended (if set to 1) 185 * Bits 7-15: Reserved (set to 0). */ 186 HBUINT16 lowestRecPPEM; /* Smallest readable size in pixels. */ 187 HBINT16 fontDirectionHint; /* Deprecated (Set to 2). 188 * 0: Fully mixed directional glyphs; 189 * 1: Only strongly left to right; 190 * 2: Like 1 but also contains neutrals; 191 * -1: Only strongly right to left; 192 * -2: Like -1 but also contains neutrals. */ 193 public: 194 HBUINT16 indexToLocFormat; /* 0 for short offsets, 1 for long. */ 195 HBUINT16 glyphDataFormat; /* 0 for current format. */ 196 197 DEFINE_SIZE_STATIC (54); 198 }; 199 200 201 } /* namespace OT */ 202 203 204 #endif /* HB_OT_HEAD_TABLE_HH */ 205