third_party/harfbuzz-ng/src/hb-ot-head-table.hh

   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-private.hh"
  33
  34
  35 namespace OT {
  36
  37
  38 /*
  39  * head -- Font Header
  40  */
  41
  42 #define HB_OT_TAG_head HB_TAG('h','e','a','d')
  43
  44 struct head
  45 {
  46   static const hb_tag_t tableTag        = HB_OT_TAG_head;
  47
  48   inline unsigned int get_upem (void) const {
  49     unsigned int upem = unitsPerEm;
  50     /* If no valid head table found, assume 1000, which matches typical Type1 usage. */
  51     return 16 <= upem && upem <= 16384 ? upem : 1000;
  52   }
  53
  54   inline bool sanitize (hb_sanitize_context_t *c) {
  55     TRACE_SANITIZE (this);
  56     return TRACE_RETURN (c->check_struct (this) && likely (version.major == 1));
  57   }
  58
  59   protected:
  60   FixedVersion  version;                /* Version of the head table--currently
  61                                          * 0x00010000 for version 1.0. */
  62   FixedVersion  fontRevision;           /* Set by font manufacturer. */
  63   ULONG         checkSumAdjustment;     /* To compute: set it to 0, sum the
  64                                          * entire font as ULONG, then store
  65                                          * 0xB1B0AFBA - sum. */
  66   ULONG         magicNumber;            /* Set to 0x5F0F3CF5. */
  67   USHORT        flags;                  /* Bit 0: Baseline for font at y=0;
  68                                          * Bit 1: Left sidebearing point at x=0;
  69                                          * Bit 2: Instructions may depend on point size;
  70                                          * Bit 3: Force ppem to integer values for all
  71                                          *   internal scaler math; may use fractional
  72                                          *   ppem sizes if this bit is clear;
  73                                          * Bit 4: Instructions may alter advance width
  74                                          *   (the advance widths might not scale linearly);
  75
  76                                          * Bits 5-10: These should be set according to
  77                                          *   Apple's specification. However, they are not
  78                                          *   implemented in OpenType.
  79                                          * Bit 5: This bit should be set in fonts that are
  80                                          *   intended to e laid out vertically, and in
  81                                          *   which the glyphs have been drawn such that an
  82                                          *   x-coordinate of 0 corresponds to the desired
  83                                          *   vertical baseline.
  84                                          * Bit 6: This bit must be set to zero.
  85                                          * Bit 7: This bit should be set if the font
  86                                          *   requires layout for correct linguistic
  87                                          *   rendering (e.g. Arabic fonts).
  88                                          * Bit 8: This bit should be set for a GX font
  89                                          *   which has one or more metamorphosis effects
  90                                          *   designated as happening by default.
  91                                          * Bit 9: This bit should be set if the font
  92                                          *   contains any strong right-to-left glyphs.
  93                                          * Bit 10: This bit should be set if the font
  94                                          *   contains Indic-style rearrangement effects.
  95
  96                                          * Bit 11: Font data is 'lossless,' as a result
  97                                          *   of having been compressed and decompressed
  98                                          *   with the Agfa MicroType Express engine.
  99                                          * Bit 12: Font converted (produce compatible metrics)
 100                                          * Bit 13: Font optimized for ClearType™.
 101                                          *   Note, fonts that rely on embedded bitmaps (EBDT)
 102                                          *   for rendering should not be considered optimized
 103                                          *   for ClearType, and therefore should keep this bit
 104                                          *   cleared.
 105                                          * Bit 14: Last Resort font. If set, indicates that
 106                                          * the glyphs encoded in the cmap subtables are simply
 107                                          * generic symbolic representations of code point
 108                                          * ranges and don’t truly represent support for those
 109                                          * code points. If unset, indicates that the glyphs
 110                                          * encoded in the cmap subtables represent proper
 111                                          * support for those code points.
 112                                          * Bit 15: Reserved, set to 0. */
 113   USHORT        unitsPerEm;             /* Valid range is from 16 to 16384. This value
 114                                          * should be a power of 2 for fonts that have
 115                                          * TrueType outlines. */
 116   LONGDATETIME  created;                /* Number of seconds since 12:00 midnight,
 117                                            January 1, 1904. 64-bit integer */
 118   LONGDATETIME  modified;               /* Number of seconds since 12:00 midnight,
 119                                            January 1, 1904. 64-bit integer */
 120   SHORT         xMin;                   /* For all glyph bounding boxes. */
 121   SHORT         yMin;                   /* For all glyph bounding boxes. */
 122   SHORT         xMax;                   /* For all glyph bounding boxes. */
 123   SHORT         yMax;                   /* For all glyph bounding boxes. */
 124   USHORT        macStyle;               /* Bit 0: Bold (if set to 1);
 125                                          * Bit 1: Italic (if set to 1)
 126                                          * Bit 2: Underline (if set to 1)
 127                                          * Bit 3: Outline (if set to 1)
 128                                          * Bit 4: Shadow (if set to 1)
 129                                          * Bit 5: Condensed (if set to 1)
 130                                          * Bit 6: Extended (if set to 1)
 131                                          * Bits 7-15: Reserved (set to 0). */
 132   USHORT        lowestRecPPEM;          /* Smallest readable size in pixels. */
 133   SHORT         fontDirectionHint;      /* Deprecated (Set to 2).
 134                                          * 0: Fully mixed directional glyphs;
 135                                          * 1: Only strongly left to right;
 136                                          * 2: Like 1 but also contains neutrals;
 137                                          * -1: Only strongly right to left;
 138                                          * -2: Like -1 but also contains neutrals. */
 139   SHORT         indexToLocFormat;       /* 0 for short offsets, 1 for long. */
 140   SHORT         glyphDataFormat;        /* 0 for current format. */
 141   public:
 142   DEFINE_SIZE_STATIC (54);
 143 };
 144
 145
 146 } /* namespace OT */
 147
 148
 149 #endif /* HB_OT_HEAD_TABLE_HH */