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      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 dont 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 */
    150