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harfbuzz/src/hb-ot-math-table.hh
Behdad Esfahbod dff2c45f1e Port rest from VAR to UnsizedArrayOf<>
2018-09-11 01:01:08 +02:00

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/*
* Copyright © 2016 Igalia S.L.
*
* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
* Igalia Author(s): Frédéric Wang
*/
#ifndef HB_OT_MATH_TABLE_HH
#define HB_OT_MATH_TABLE_HH
#include "hb-open-type.hh"
#include "hb-ot-layout-common.hh"
#include "hb-ot-math.h"
namespace OT {
struct MathValueRecord
{
inline hb_position_t get_x_value (hb_font_t *font, const void *base) const
{ return font->em_scale_x (value) + (base+deviceTable).get_x_delta (font); }
inline hb_position_t get_y_value (hb_font_t *font, const void *base) const
{ return font->em_scale_y (value) + (base+deviceTable).get_y_delta (font); }
inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) && deviceTable.sanitize (c, base));
}
protected:
HBINT16 value; /* The X or Y value in design units */
OffsetTo<Device> deviceTable; /* Offset to the device table - from the
* beginning of parent table. May be nullptr.
* Suggested format for device table is 1. */
public:
DEFINE_SIZE_STATIC (4);
};
struct MathConstants
{
inline bool sanitize_math_value_records (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
unsigned int count = ARRAY_LENGTH (mathValueRecords);
for (unsigned int i = 0; i < count; i++)
if (!mathValueRecords[i].sanitize (c, this))
return_trace (false);
return_trace (true);
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) && sanitize_math_value_records(c));
}
inline hb_position_t get_value (hb_ot_math_constant_t constant,
hb_font_t *font) const
{
switch (constant) {
case HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN:
case HB_OT_MATH_CONSTANT_SCRIPT_SCRIPT_PERCENT_SCALE_DOWN:
return percentScaleDown[constant - HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN];
case HB_OT_MATH_CONSTANT_DELIMITED_SUB_FORMULA_MIN_HEIGHT:
case HB_OT_MATH_CONSTANT_DISPLAY_OPERATOR_MIN_HEIGHT:
return font->em_scale_y (minHeight[constant - HB_OT_MATH_CONSTANT_DELIMITED_SUB_FORMULA_MIN_HEIGHT]);
case HB_OT_MATH_CONSTANT_RADICAL_KERN_AFTER_DEGREE:
case HB_OT_MATH_CONSTANT_RADICAL_KERN_BEFORE_DEGREE:
case HB_OT_MATH_CONSTANT_SKEWED_FRACTION_HORIZONTAL_GAP:
case HB_OT_MATH_CONSTANT_SPACE_AFTER_SCRIPT:
return mathValueRecords[constant - HB_OT_MATH_CONSTANT_MATH_LEADING].get_x_value(font, this);
case HB_OT_MATH_CONSTANT_ACCENT_BASE_HEIGHT:
case HB_OT_MATH_CONSTANT_AXIS_HEIGHT:
case HB_OT_MATH_CONSTANT_FLATTENED_ACCENT_BASE_HEIGHT:
case HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_DISPLAY_STYLE_SHIFT_DOWN:
case HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_GAP_MIN:
case HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_SHIFT_DOWN:
case HB_OT_MATH_CONSTANT_FRACTION_DENOM_DISPLAY_STYLE_GAP_MIN:
case HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_DISPLAY_STYLE_SHIFT_UP:
case HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_GAP_MIN:
case HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_SHIFT_UP:
case HB_OT_MATH_CONSTANT_FRACTION_NUM_DISPLAY_STYLE_GAP_MIN:
case HB_OT_MATH_CONSTANT_FRACTION_RULE_THICKNESS:
case HB_OT_MATH_CONSTANT_LOWER_LIMIT_BASELINE_DROP_MIN:
case HB_OT_MATH_CONSTANT_LOWER_LIMIT_GAP_MIN:
case HB_OT_MATH_CONSTANT_MATH_LEADING:
case HB_OT_MATH_CONSTANT_OVERBAR_EXTRA_ASCENDER:
case HB_OT_MATH_CONSTANT_OVERBAR_RULE_THICKNESS:
case HB_OT_MATH_CONSTANT_OVERBAR_VERTICAL_GAP:
case HB_OT_MATH_CONSTANT_RADICAL_DISPLAY_STYLE_VERTICAL_GAP:
case HB_OT_MATH_CONSTANT_RADICAL_EXTRA_ASCENDER:
case HB_OT_MATH_CONSTANT_RADICAL_RULE_THICKNESS:
case HB_OT_MATH_CONSTANT_RADICAL_VERTICAL_GAP:
case HB_OT_MATH_CONSTANT_SKEWED_FRACTION_VERTICAL_GAP:
case HB_OT_MATH_CONSTANT_STACK_BOTTOM_DISPLAY_STYLE_SHIFT_DOWN:
case HB_OT_MATH_CONSTANT_STACK_BOTTOM_SHIFT_DOWN:
case HB_OT_MATH_CONSTANT_STACK_DISPLAY_STYLE_GAP_MIN:
case HB_OT_MATH_CONSTANT_STACK_GAP_MIN:
case HB_OT_MATH_CONSTANT_STACK_TOP_DISPLAY_STYLE_SHIFT_UP:
case HB_OT_MATH_CONSTANT_STACK_TOP_SHIFT_UP:
case HB_OT_MATH_CONSTANT_STRETCH_STACK_BOTTOM_SHIFT_DOWN:
case HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_ABOVE_MIN:
case HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_BELOW_MIN:
case HB_OT_MATH_CONSTANT_STRETCH_STACK_TOP_SHIFT_UP:
case HB_OT_MATH_CONSTANT_SUBSCRIPT_BASELINE_DROP_MIN:
case HB_OT_MATH_CONSTANT_SUBSCRIPT_SHIFT_DOWN:
case HB_OT_MATH_CONSTANT_SUBSCRIPT_TOP_MAX:
case HB_OT_MATH_CONSTANT_SUB_SUPERSCRIPT_GAP_MIN:
case HB_OT_MATH_CONSTANT_SUPERSCRIPT_BASELINE_DROP_MAX:
case HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MAX_WITH_SUBSCRIPT:
case HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MIN:
case HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP:
case HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP_CRAMPED:
case HB_OT_MATH_CONSTANT_UNDERBAR_EXTRA_DESCENDER:
case HB_OT_MATH_CONSTANT_UNDERBAR_RULE_THICKNESS:
case HB_OT_MATH_CONSTANT_UNDERBAR_VERTICAL_GAP:
case HB_OT_MATH_CONSTANT_UPPER_LIMIT_BASELINE_RISE_MIN:
case HB_OT_MATH_CONSTANT_UPPER_LIMIT_GAP_MIN:
return mathValueRecords[constant - HB_OT_MATH_CONSTANT_MATH_LEADING].get_y_value(font, this);
case HB_OT_MATH_CONSTANT_RADICAL_DEGREE_BOTTOM_RAISE_PERCENT:
return radicalDegreeBottomRaisePercent;
default:
return 0;
}
}
protected:
HBINT16 percentScaleDown[2];
HBUINT16 minHeight[2];
MathValueRecord mathValueRecords[51];
HBINT16 radicalDegreeBottomRaisePercent;
public:
DEFINE_SIZE_STATIC (214);
};
struct MathItalicsCorrectionInfo
{
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) &&
coverage.sanitize (c, this) &&
italicsCorrection.sanitize (c, this));
}
inline hb_position_t get_value (hb_codepoint_t glyph,
hb_font_t *font) const
{
unsigned int index = (this+coverage).get_coverage (glyph);
return italicsCorrection[index].get_x_value (font, this);
}
protected:
OffsetTo<Coverage> coverage; /* Offset to Coverage table -
* from the beginning of
* MathItalicsCorrectionInfo
* table. */
ArrayOf<MathValueRecord> italicsCorrection; /* Array of MathValueRecords
* defining italics correction
* values for each
* covered glyph. */
public:
DEFINE_SIZE_ARRAY (4, italicsCorrection);
};
struct MathTopAccentAttachment
{
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) &&
topAccentCoverage.sanitize (c, this) &&
topAccentAttachment.sanitize (c, this));
}
inline hb_position_t get_value (hb_codepoint_t glyph,
hb_font_t *font) const
{
unsigned int index = (this+topAccentCoverage).get_coverage (glyph);
if (index == NOT_COVERED)
return font->get_glyph_h_advance (glyph) / 2;
return topAccentAttachment[index].get_x_value(font, this);
}
protected:
OffsetTo<Coverage> topAccentCoverage; /* Offset to Coverage table -
* from the beginning of
* MathTopAccentAttachment
* table. */
ArrayOf<MathValueRecord> topAccentAttachment; /* Array of MathValueRecords
* defining top accent
* attachment points for each
* covered glyph. */
public:
DEFINE_SIZE_ARRAY (2 + 2, topAccentAttachment);
};
struct MathKern
{
inline bool sanitize_math_value_records (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
unsigned int count = 2 * heightCount + 1;
for (unsigned int i = 0; i < count; i++)
if (!mathValueRecordsZ.arrayZ[i].sanitize (c, this)) return_trace (false);
return_trace (true);
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) &&
c->check_array (mathValueRecordsZ.arrayZ, 2 * heightCount + 1) &&
sanitize_math_value_records (c));
}
inline hb_position_t get_value (hb_position_t correction_height, hb_font_t *font) const
{
const MathValueRecord* correctionHeight = mathValueRecordsZ.arrayZ;
const MathValueRecord* kernValue = mathValueRecordsZ.arrayZ + heightCount;
int sign = font->y_scale < 0 ? -1 : +1;
/* The description of the MathKern table is a ambiguous, but interpreting
* "between the two heights found at those indexes" for 0 < i < len as
*
* correctionHeight[i-1] < correction_height <= correctionHeight[i]
*
* makes the result consistent with the limit cases and we can just use the
* binary search algorithm of std::upper_bound:
*/
unsigned int i = 0;
unsigned int count = heightCount;
while (count > 0)
{
unsigned int half = count / 2;
hb_position_t height = correctionHeight[i + half].get_y_value(font, this);
if (sign * height < sign * correction_height)
{
i += half + 1;
count -= half + 1;
} else
count = half;
}
return kernValue[i].get_x_value(font, this);
}
protected:
HBUINT16 heightCount;
UnsizedArrayOf<MathValueRecord>
mathValueRecordsZ; /* Array of correction heights at
* which the kern value changes.
* Sorted by the height value in
* design units (heightCount entries),
* Followed by:
* Array of kern values corresponding
* to heights. (heightCount+1 entries).
*/
public:
DEFINE_SIZE_ARRAY (2, mathValueRecordsZ);
};
struct MathKernInfoRecord
{
inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
{
TRACE_SANITIZE (this);
unsigned int count = ARRAY_LENGTH (mathKern);
for (unsigned int i = 0; i < count; i++)
if (unlikely (!mathKern[i].sanitize (c, base)))
return_trace (false);
return_trace (true);
}
inline hb_position_t get_kerning (hb_ot_math_kern_t kern,
hb_position_t correction_height,
hb_font_t *font,
const void *base) const
{
unsigned int idx = kern;
if (unlikely (idx >= ARRAY_LENGTH (mathKern))) return 0;
return (base+mathKern[idx]).get_value (correction_height, font);
}
protected:
/* Offset to MathKern table for each corner -
* from the beginning of MathKernInfo table. May be nullptr. */
OffsetTo<MathKern> mathKern[4];
public:
DEFINE_SIZE_STATIC (8);
};
struct MathKernInfo
{
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) &&
mathKernCoverage.sanitize (c, this) &&
mathKernInfoRecords.sanitize (c, this));
}
inline hb_position_t get_kerning (hb_codepoint_t glyph,
hb_ot_math_kern_t kern,
hb_position_t correction_height,
hb_font_t *font) const
{
unsigned int index = (this+mathKernCoverage).get_coverage (glyph);
return mathKernInfoRecords[index].get_kerning (kern, correction_height, font, this);
}
protected:
OffsetTo<Coverage> mathKernCoverage; /* Offset to Coverage table -
* from the beginning of the
* MathKernInfo table. */
ArrayOf<MathKernInfoRecord> mathKernInfoRecords; /* Array of
* MathKernInfoRecords,
* per-glyph information for
* mathematical positioning
* of subscripts and
* superscripts. */
public:
DEFINE_SIZE_ARRAY (4, mathKernInfoRecords);
};
struct MathGlyphInfo
{
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) &&
mathItalicsCorrectionInfo.sanitize (c, this) &&
mathTopAccentAttachment.sanitize (c, this) &&
extendedShapeCoverage.sanitize (c, this) &&
mathKernInfo.sanitize(c, this));
}
inline hb_position_t
get_italics_correction (hb_codepoint_t glyph, hb_font_t *font) const
{ return (this+mathItalicsCorrectionInfo).get_value (glyph, font); }
inline hb_position_t
get_top_accent_attachment (hb_codepoint_t glyph, hb_font_t *font) const
{ return (this+mathTopAccentAttachment).get_value (glyph, font); }
inline bool is_extended_shape (hb_codepoint_t glyph) const
{ return (this+extendedShapeCoverage).get_coverage (glyph) != NOT_COVERED; }
inline hb_position_t get_kerning (hb_codepoint_t glyph,
hb_ot_math_kern_t kern,
hb_position_t correction_height,
hb_font_t *font) const
{ return (this+mathKernInfo).get_kerning (glyph, kern, correction_height, font); }
protected:
/* Offset to MathItalicsCorrectionInfo table -
* from the beginning of MathGlyphInfo table. */
OffsetTo<MathItalicsCorrectionInfo> mathItalicsCorrectionInfo;
/* Offset to MathTopAccentAttachment table -
* from the beginning of MathGlyphInfo table. */
OffsetTo<MathTopAccentAttachment> mathTopAccentAttachment;
/* Offset to coverage table for Extended Shape glyphs -
* from the beginning of MathGlyphInfo table. When the left or right glyph of
* a box is an extended shape variant, the (ink) box (and not the default
* position defined by values in MathConstants table) should be used for
* vertical positioning purposes. May be nullptr.. */
OffsetTo<Coverage> extendedShapeCoverage;
/* Offset to MathKernInfo table -
* from the beginning of MathGlyphInfo table. */
OffsetTo<MathKernInfo> mathKernInfo;
public:
DEFINE_SIZE_STATIC (8);
};
struct MathGlyphVariantRecord
{
friend struct MathGlyphConstruction;
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this));
}
protected:
GlyphID variantGlyph; /* Glyph ID for the variant. */
HBUINT16 advanceMeasurement; /* Advance width/height, in design units, of the
* variant, in the direction of requested
* glyph extension. */
public:
DEFINE_SIZE_STATIC (4);
};
struct PartFlags : HBUINT16
{
enum Flags {
Extender = 0x0001u, /* If set, the part can be skipped or repeated. */
Defined = 0x0001u, /* All defined flags. */
};
public:
DEFINE_SIZE_STATIC (2);
};
struct MathGlyphPartRecord
{
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this));
}
inline void extract (hb_ot_math_glyph_part_t &out,
int scale,
hb_font_t *font) const
{
out.glyph = glyph;
out.start_connector_length = font->em_scale (startConnectorLength, scale);
out.end_connector_length = font->em_scale (endConnectorLength, scale);
out.full_advance = font->em_scale (fullAdvance, scale);
static_assert ((unsigned int) HB_MATH_GLYPH_PART_FLAG_EXTENDER ==
(unsigned int) PartFlags::Extender, "");
out.flags = (hb_ot_math_glyph_part_flags_t)
(unsigned int)
(partFlags & PartFlags::Defined);
}
protected:
GlyphID glyph; /* Glyph ID for the part. */
HBUINT16 startConnectorLength; /* Advance width/ height of the straight bar
* connector material, in design units, is at
* the beginning of the glyph, in the
* direction of the extension. */
HBUINT16 endConnectorLength; /* Advance width/ height of the straight bar
* connector material, in design units, is at
* the end of the glyph, in the direction of
* the extension. */
HBUINT16 fullAdvance; /* Full advance width/height for this part,
* in the direction of the extension.
* In design units. */
PartFlags partFlags; /* Part qualifiers. */
public:
DEFINE_SIZE_STATIC (10);
};
struct MathGlyphAssembly
{
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) &&
italicsCorrection.sanitize(c, this) &&
partRecords.sanitize(c));
}
inline unsigned int get_parts (hb_direction_t direction,
hb_font_t *font,
unsigned int start_offset,
unsigned int *parts_count, /* IN/OUT */
hb_ot_math_glyph_part_t *parts /* OUT */,
hb_position_t *italics_correction /* OUT */) const
{
if (parts_count)
{
int scale = font->dir_scale (direction);
const MathGlyphPartRecord *arr =
partRecords.sub_array (start_offset, parts_count);
unsigned int count = *parts_count;
for (unsigned int i = 0; i < count; i++)
arr[i].extract (parts[i], scale, font);
}
if (italics_correction)
*italics_correction = italicsCorrection.get_x_value (font, this);
return partRecords.len;
}
protected:
MathValueRecord italicsCorrection; /* Italics correction of this
* MathGlyphAssembly. Should not
* depend on the assembly size. */
ArrayOf<MathGlyphPartRecord> partRecords; /* Array of part records, from
* left to right and bottom to
* top. */
public:
DEFINE_SIZE_ARRAY (6, partRecords);
};
struct MathGlyphConstruction
{
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) &&
glyphAssembly.sanitize(c, this) &&
mathGlyphVariantRecord.sanitize(c));
}
inline const MathGlyphAssembly &get_assembly (void) const
{ return this+glyphAssembly; }
inline unsigned int get_variants (hb_direction_t direction,
hb_font_t *font,
unsigned int start_offset,
unsigned int *variants_count, /* IN/OUT */
hb_ot_math_glyph_variant_t *variants /* OUT */) const
{
if (variants_count)
{
int scale = font->dir_scale (direction);
const MathGlyphVariantRecord *arr =
mathGlyphVariantRecord.sub_array (start_offset, variants_count);
unsigned int count = *variants_count;
for (unsigned int i = 0; i < count; i++)
{
variants[i].glyph = arr[i].variantGlyph;
variants[i].advance = font->em_scale (arr[i].advanceMeasurement, scale);
}
}
return mathGlyphVariantRecord.len;
}
protected:
/* Offset to MathGlyphAssembly table for this shape - from the beginning of
MathGlyphConstruction table. May be nullptr. */
OffsetTo<MathGlyphAssembly> glyphAssembly;
/* MathGlyphVariantRecords for alternative variants of the glyphs. */
ArrayOf<MathGlyphVariantRecord> mathGlyphVariantRecord;
public:
DEFINE_SIZE_ARRAY (4, mathGlyphVariantRecord);
};
struct MathVariants
{
inline bool sanitize_offsets (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
unsigned int count = vertGlyphCount + horizGlyphCount;
for (unsigned int i = 0; i < count; i++)
if (!glyphConstruction.arrayZ[i].sanitize (c, this)) return_trace (false);
return_trace (true);
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) &&
vertGlyphCoverage.sanitize (c, this) &&
horizGlyphCoverage.sanitize (c, this) &&
c->check_array (glyphConstruction.arrayZ, vertGlyphCount + horizGlyphCount) &&
sanitize_offsets (c));
}
inline hb_position_t get_min_connector_overlap (hb_direction_t direction,
hb_font_t *font) const
{ return font->em_scale_dir (minConnectorOverlap, direction); }
inline unsigned int get_glyph_variants (hb_codepoint_t glyph,
hb_direction_t direction,
hb_font_t *font,
unsigned int start_offset,
unsigned int *variants_count, /* IN/OUT */
hb_ot_math_glyph_variant_t *variants /* OUT */) const
{ return get_glyph_construction (glyph, direction, font)
.get_variants (direction, font, start_offset, variants_count, variants); }
inline unsigned int get_glyph_parts (hb_codepoint_t glyph,
hb_direction_t direction,
hb_font_t *font,
unsigned int start_offset,
unsigned int *parts_count, /* IN/OUT */
hb_ot_math_glyph_part_t *parts /* OUT */,
hb_position_t *italics_correction /* OUT */) const
{ return get_glyph_construction (glyph, direction, font)
.get_assembly ()
.get_parts (direction, font,
start_offset, parts_count, parts,
italics_correction); }
private:
inline const MathGlyphConstruction &
get_glyph_construction (hb_codepoint_t glyph,
hb_direction_t direction,
hb_font_t *font) const
{
bool vertical = HB_DIRECTION_IS_VERTICAL (direction);
unsigned int count = vertical ? vertGlyphCount : horizGlyphCount;
const OffsetTo<Coverage> &coverage = vertical ? vertGlyphCoverage
: horizGlyphCoverage;
unsigned int index = (this+coverage).get_coverage (glyph);
if (unlikely (index >= count)) return Null(MathGlyphConstruction);
if (!vertical)
index += vertGlyphCount;
return this+glyphConstruction[index];
}
protected:
HBUINT16 minConnectorOverlap; /* Minimum overlap of connecting
* glyphs during glyph construction,
* in design units. */
OffsetTo<Coverage> vertGlyphCoverage; /* Offset to Coverage table -
* from the beginning of MathVariants
* table. */
OffsetTo<Coverage> horizGlyphCoverage; /* Offset to Coverage table -
* from the beginning of MathVariants
* table. */
HBUINT16 vertGlyphCount; /* Number of glyphs for which
* information is provided for
* vertically growing variants. */
HBUINT16 horizGlyphCount; /* Number of glyphs for which
* information is provided for
* horizontally growing variants. */
/* Array of offsets to MathGlyphConstruction tables - from the beginning of
the MathVariants table, for shapes growing in vertical/horizontal
direction. */
UnsizedArrayOf<OffsetTo<MathGlyphConstruction> >
glyphConstruction;
public:
DEFINE_SIZE_ARRAY (10, glyphConstruction);
};
/*
* MATH -- Mathematical typesetting
* https://docs.microsoft.com/en-us/typography/opentype/spec/math
*/
struct MATH
{
static const hb_tag_t tableTag = HB_OT_TAG_MATH;
inline bool has_data (void) const { return version.to_int () != 0; }
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (version.sanitize (c) &&
likely (version.major == 1) &&
mathConstants.sanitize (c, this) &&
mathGlyphInfo.sanitize (c, this) &&
mathVariants.sanitize (c, this));
}
inline hb_position_t get_constant (hb_ot_math_constant_t constant,
hb_font_t *font) const
{ return (this+mathConstants).get_value (constant, font); }
inline const MathGlyphInfo &get_math_glyph_info (void) const
{ return this+mathGlyphInfo; }
inline const MathVariants &get_math_variants (void) const
{ return this+mathVariants; }
protected:
FixedVersion<>version; /* Version of the MATH table
* initially set to 0x00010000u */
OffsetTo<MathConstants> mathConstants;/* MathConstants table */
OffsetTo<MathGlyphInfo> mathGlyphInfo;/* MathGlyphInfo table */
OffsetTo<MathVariants> mathVariants; /* MathVariants table */
public:
DEFINE_SIZE_STATIC (10);
};
} /* namespace OT */
#endif /* HB_OT_MATH_TABLE_HH */
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