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
41namespace OT {
42
43
44struct head
45{
46 friend struct OffsetTable;
47
48 static constexpr hb_tag_t tableTag = HB_OT_TAG_head;
49
50 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
57 enum mac_style_flag_t {
58 BOLD = 1u<<0,
59 ITALIC = 1u<<1,
60 UNDERLINE = 1u<<2,
61 OUTLINE = 1u<<3,
62 SHADOW = 1u<<4,
63 CONDENSED = 1u<<5
64 };
65
66 bool is_bold () const { return macStyle & BOLD; }
67 bool is_italic () const { return macStyle & ITALIC; }
68 bool is_condensed () const { return macStyle & CONDENSED; }
69
70 bool sanitize (hb_sanitize_context_t *c) const
71 {
72 TRACE_SANITIZE (this);
73 return_trace (c->check_struct (this) &&
74 version.major == 1 &&
75 magicNumber == 0x5F0F3CF5u);
76 }
77
78 protected:
79 FixedVersion<>version; /* Version of the head table--currently
80 * 0x00010000u for version 1.0. */
81 FixedVersion<>fontRevision; /* Set by font manufacturer. */
82 HBUINT32 checkSumAdjustment; /* To compute: set it to 0, sum the
83 * entire font as HBUINT32, then store
84 * 0xB1B0AFBAu - sum. */
85 HBUINT32 magicNumber; /* Set to 0x5F0F3CF5u. */
86 HBUINT16 flags; /* Bit 0: Baseline for font at y=0;
87 * Bit 1: Left sidebearing point at x=0;
88 * Bit 2: Instructions may depend on point size;
89 * Bit 3: Force ppem to integer values for all
90 * internal scaler math; may use fractional
91 * ppem sizes if this bit is clear;
92 * Bit 4: Instructions may alter advance width
93 * (the advance widths might not scale linearly);
94 * Bits 5-10: These should be set according to
95 * Apple's specification. However, they are not
96 * implemented in OpenType.
97 * Bit 5: This bit should be set in fonts that are
98 * intended to e laid out vertically, and in
99 * which the glyphs have been drawn such that an
100 * x-coordinate of 0 corresponds to the desired
101 * vertical baseline.
102 * Bit 6: This bit must be set to zero.
103 * Bit 7: This bit should be set if the font
104 * requires layout for correct linguistic
105 * rendering (e.g. Arabic fonts).
106 * Bit 8: This bit should be set for a GX font
107 * which has one or more metamorphosis effects
108 * designated as happening by default.
109 * Bit 9: This bit should be set if the font
110 * contains any strong right-to-left glyphs.
111 * Bit 10: This bit should be set if the font
112 * contains Indic-style rearrangement effects.
113 * Bit 11: Font data is 'lossless,' as a result
114 * of having been compressed and decompressed
115 * with the Agfa MicroType Express engine.
116 * Bit 12: Font converted (produce compatible metrics)
117 * Bit 13: Font optimized for ClearType™.
118 * Note, fonts that rely on embedded bitmaps (EBDT)
119 * for rendering should not be considered optimized
120 * for ClearType, and therefore should keep this bit
121 * cleared.
122 * Bit 14: Last Resort font. If set, indicates that
123 * the glyphs encoded in the cmap subtables are simply
124 * generic symbolic representations of code point
125 * ranges and don’t truly represent support for those
126 * code points. If unset, indicates that the glyphs
127 * encoded in the cmap subtables represent proper
128 * support for those code points.
129 * Bit 15: Reserved, set to 0. */
130 HBUINT16 unitsPerEm; /* Valid range is from 16 to 16384. This value
131 * should be a power of 2 for fonts that have
132 * TrueType outlines. */
133 LONGDATETIME created; /* Number of seconds since 12:00 midnight,
134 January 1, 1904. 64-bit integer */
135 LONGDATETIME modified; /* Number of seconds since 12:00 midnight,
136 January 1, 1904. 64-bit integer */
137 HBINT16 xMin; /* For all glyph bounding boxes. */
138 HBINT16 yMin; /* For all glyph bounding boxes. */
139 HBINT16 xMax; /* For all glyph bounding boxes. */
140 HBINT16 yMax; /* For all glyph bounding boxes. */
141 HBUINT16 macStyle; /* Bit 0: Bold (if set to 1);
142 * Bit 1: Italic (if set to 1)
143 * Bit 2: Underline (if set to 1)
144 * Bit 3: Outline (if set to 1)
145 * Bit 4: Shadow (if set to 1)
146 * Bit 5: Condensed (if set to 1)
147 * Bit 6: Extended (if set to 1)
148 * Bits 7-15: Reserved (set to 0). */
149 HBUINT16 lowestRecPPEM; /* Smallest readable size in pixels. */
150 HBINT16 fontDirectionHint; /* Deprecated (Set to 2).
151 * 0: Fully mixed directional glyphs;
152 * 1: Only strongly left to right;
153 * 2: Like 1 but also contains neutrals;
154 * -1: Only strongly right to left;
155 * -2: Like -1 but also contains neutrals. */
156 public:
157 HBUINT16 indexToLocFormat; /* 0 for short offsets, 1 for long. */
158 HBUINT16 glyphDataFormat; /* 0 for current format. */
159
160 DEFINE_SIZE_STATIC (54);
161};
162
163
164} /* namespace OT */
165
166
167#endif /* HB_OT_HEAD_TABLE_HH */
168