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Diffstat (limited to 'gfx/harfbuzz/src/hb-ot-math-table.hh')
| -rw-r--r-- | gfx/harfbuzz/src/hb-ot-math-table.hh | 728 |
1 files changed, 728 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-ot-math-table.hh b/gfx/harfbuzz/src/hb-ot-math-table.hh new file mode 100644 index 0000000000..26aa080603 --- /dev/null +++ b/gfx/harfbuzz/src/hb-ot-math-table.hh @@ -0,0 +1,728 @@ +/* + * 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 +{ + 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); } + 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); } + + 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 NULL. + * Suggested format for device table is 1. */ + + public: + DEFINE_SIZE_STATIC (4); +}; + +struct MathConstants +{ + 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); + } + + bool sanitize (hb_sanitize_context_t *c) const + { + TRACE_SANITIZE (this); + return_trace (c->check_struct (this) && sanitize_math_value_records (c)); + } + + 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 +{ + 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)); + } + + 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 +{ + 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)); + } + + 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 +{ + 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); + } + + 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)); + } + + 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 +{ + 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); + } + + 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 NULL. */ + OffsetTo<MathKern> mathKern[4]; + + public: + DEFINE_SIZE_STATIC (8); +}; + +struct MathKernInfo +{ + 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)); + } + + 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 +{ + 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)); + } + + hb_position_t + get_italics_correction (hb_codepoint_t glyph, hb_font_t *font) const + { return (this+mathItalicsCorrectionInfo).get_value (glyph, font); } + + hb_position_t + get_top_accent_attachment (hb_codepoint_t glyph, hb_font_t *font) const + { return (this+mathTopAccentAttachment).get_value (glyph, font); } + + bool is_extended_shape (hb_codepoint_t glyph) const + { return (this+extendedShapeCoverage).get_coverage (glyph) != NOT_COVERED; } + + 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 NULL.. */ + 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; + + bool sanitize (hb_sanitize_context_t *c) const + { + TRACE_SANITIZE (this); + return_trace (c->check_struct (this)); + } + + protected: + HBGlyphID 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 +{ + bool sanitize (hb_sanitize_context_t *c) const + { + TRACE_SANITIZE (this); + return_trace (c->check_struct (this)); + } + + void extract (hb_ot_math_glyph_part_t &out, + int64_t mult, + hb_font_t *font) const + { + out.glyph = glyph; + + out.start_connector_length = font->em_mult (startConnectorLength, mult); + out.end_connector_length = font->em_mult (endConnectorLength, mult); + out.full_advance = font->em_mult (fullAdvance, mult); + + static_assert ((unsigned int) HB_OT_MATH_GLYPH_PART_FLAG_EXTENDER == + (unsigned int) PartFlags::Extender, ""); + + out.flags = (hb_ot_math_glyph_part_flags_t) + (unsigned int) + (partFlags & PartFlags::Defined); + } + + protected: + HBGlyphID 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 +{ + bool sanitize (hb_sanitize_context_t *c) const + { + TRACE_SANITIZE (this); + return_trace (c->check_struct (this) && + italicsCorrection.sanitize (c, this) && + partRecords.sanitize (c)); + } + + 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) + { + int64_t mult = font->dir_mult (direction); + for (auto _ : hb_zip (partRecords.sub_array (start_offset, parts_count), + hb_array (parts, *parts_count))) + _.first.extract (_.second, mult, 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 +{ + bool sanitize (hb_sanitize_context_t *c) const + { + TRACE_SANITIZE (this); + return_trace (c->check_struct (this) && + glyphAssembly.sanitize (c, this) && + mathGlyphVariantRecord.sanitize (c)); + } + + const MathGlyphAssembly &get_assembly () const { return this+glyphAssembly; } + + 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) + { + int64_t mult = font->dir_mult (direction); + for (auto _ : hb_zip (mathGlyphVariantRecord.sub_array (start_offset, variants_count), + hb_array (variants, *variants_count))) + _.second = {_.first.variantGlyph, font->em_mult (_.first.advanceMeasurement, mult)}; + } + return mathGlyphVariantRecord.len; + } + + protected: + /* Offset to MathGlyphAssembly table for this shape - from the beginning of + MathGlyphConstruction table. May be NULL. */ + OffsetTo<MathGlyphAssembly> glyphAssembly; + + /* MathGlyphVariantRecords for alternative variants of the glyphs. */ + ArrayOf<MathGlyphVariantRecord> mathGlyphVariantRecord; + + public: + DEFINE_SIZE_ARRAY (4, mathGlyphVariantRecord); +}; + +struct MathVariants +{ + 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); + } + + 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)); + } + + hb_position_t get_min_connector_overlap (hb_direction_t direction, + hb_font_t *font) const + { return font->em_scale_dir (minConnectorOverlap, direction); } + + 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); } + + 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: + const MathGlyphConstruction & + get_glyph_construction (hb_codepoint_t glyph, + hb_direction_t direction, + hb_font_t *font HB_UNUSED) 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 constexpr hb_tag_t tableTag = HB_OT_TAG_MATH; + + bool has_data () const { return version.to_int (); } + + 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)); + } + + hb_position_t get_constant (hb_ot_math_constant_t constant, + hb_font_t *font) const + { return (this+mathConstants).get_value (constant, font); } + + const MathGlyphInfo &get_glyph_info () const { return this+mathGlyphInfo; } + + const MathVariants &get_variants () 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 */ |