include/harfbuzz/hb-ot-math.h

0001 /*
0002  * Copyright © 2016  Igalia S.L.
0003  *
0004  *  This is part of HarfBuzz, a text shaping library.
0005  *
0006  * Permission is hereby granted, without written agreement and without
0007  * license or royalty fees, to use, copy, modify, and distribute this
0008  * software and its documentation for any purpose, provided that the
0009  * above copyright notice and the following two paragraphs appear in
0010  * all copies of this software.
0011  *
0012  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
0013  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
0014  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
0015  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
0016  * DAMAGE.
0017  *
0018  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
0019  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
0020  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
0021  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
0022  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
0023  *
0024  * Igalia Author(s): Frédéric Wang
0025  */
0026
0027 #if !defined(HB_OT_H_IN) && !defined(HB_NO_SINGLE_HEADER_ERROR)
0028 #error "Include <hb-ot.h> instead."
0029 #endif
0030
0031 #ifndef HB_OT_MATH_H
0032 #define HB_OT_MATH_H
0033
0034 #include "hb.h"
0035
0036 HB_BEGIN_DECLS
0037
0038
0039 /*
0040  * MATH
0041  */
0042
0043 /**
0044  * HB_OT_TAG_MATH:
0045  *
0046  * OpenType [Mathematical Typesetting Table](https://docs.microsoft.com/en-us/typography/opentype/spec/math).
0047  *
0048  * Since: 1.3.3
0049  */
0050 #define HB_OT_TAG_MATH HB_TAG('M','A','T','H')
0051
0052 /**
0053  * HB_OT_TAG_MATH_SCRIPT:
0054  *
0055  * OpenType script tag, `math`, for features specific to math shaping.
0056  *
0057  * <note>#HB_OT_TAG_MATH_SCRIPT is not a valid #hb_script_t and should only be
0058  * used with functions that accept raw OpenType script tags, such as
0059  * #hb_ot_layout_collect_features. In other cases, #HB_SCRIPT_MATH should be
0060  * used instead.</note>
0061  *
0062  * Since: 3.4.0
0063  */
0064 #define HB_OT_TAG_MATH_SCRIPT HB_TAG('m','a','t','h')
0065
0066 /* Types */
0067
0068 /**
0069  * hb_ot_math_constant_t:
0070  * @HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN: scriptPercentScaleDown
0071  * @HB_OT_MATH_CONSTANT_SCRIPT_SCRIPT_PERCENT_SCALE_DOWN: scriptScriptPercentScaleDown
0072  * @HB_OT_MATH_CONSTANT_DELIMITED_SUB_FORMULA_MIN_HEIGHT: delimitedSubFormulaMinHeight
0073  * @HB_OT_MATH_CONSTANT_DISPLAY_OPERATOR_MIN_HEIGHT: displayOperatorMinHeight
0074  * @HB_OT_MATH_CONSTANT_MATH_LEADING: mathLeading
0075  * @HB_OT_MATH_CONSTANT_AXIS_HEIGHT: axisHeight
0076  * @HB_OT_MATH_CONSTANT_ACCENT_BASE_HEIGHT: accentBaseHeight
0077  * @HB_OT_MATH_CONSTANT_FLATTENED_ACCENT_BASE_HEIGHT: flattenedAccentBaseHeight
0078  * @HB_OT_MATH_CONSTANT_SUBSCRIPT_SHIFT_DOWN: subscriptShiftDown
0079  * @HB_OT_MATH_CONSTANT_SUBSCRIPT_TOP_MAX: subscriptTopMax
0080  * @HB_OT_MATH_CONSTANT_SUBSCRIPT_BASELINE_DROP_MIN: subscriptBaselineDropMin
0081  * @HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP: superscriptShiftUp
0082  * @HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP_CRAMPED: superscriptShiftUpCramped
0083  * @HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MIN: superscriptBottomMin
0084  * @HB_OT_MATH_CONSTANT_SUPERSCRIPT_BASELINE_DROP_MAX: superscriptBaselineDropMax
0085  * @HB_OT_MATH_CONSTANT_SUB_SUPERSCRIPT_GAP_MIN: subSuperscriptGapMin
0086  * @HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MAX_WITH_SUBSCRIPT: superscriptBottomMaxWithSubscript
0087  * @HB_OT_MATH_CONSTANT_SPACE_AFTER_SCRIPT: spaceAfterScript
0088  * @HB_OT_MATH_CONSTANT_UPPER_LIMIT_GAP_MIN: upperLimitGapMin
0089  * @HB_OT_MATH_CONSTANT_UPPER_LIMIT_BASELINE_RISE_MIN: upperLimitBaselineRiseMin
0090  * @HB_OT_MATH_CONSTANT_LOWER_LIMIT_GAP_MIN: lowerLimitGapMin
0091  * @HB_OT_MATH_CONSTANT_LOWER_LIMIT_BASELINE_DROP_MIN: lowerLimitBaselineDropMin
0092  * @HB_OT_MATH_CONSTANT_STACK_TOP_SHIFT_UP: stackTopShiftUp
0093  * @HB_OT_MATH_CONSTANT_STACK_TOP_DISPLAY_STYLE_SHIFT_UP: stackTopDisplayStyleShiftUp
0094  * @HB_OT_MATH_CONSTANT_STACK_BOTTOM_SHIFT_DOWN: stackBottomShiftDown
0095  * @HB_OT_MATH_CONSTANT_STACK_BOTTOM_DISPLAY_STYLE_SHIFT_DOWN: stackBottomDisplayStyleShiftDown
0096  * @HB_OT_MATH_CONSTANT_STACK_GAP_MIN: stackGapMin
0097  * @HB_OT_MATH_CONSTANT_STACK_DISPLAY_STYLE_GAP_MIN: stackDisplayStyleGapMin
0098  * @HB_OT_MATH_CONSTANT_STRETCH_STACK_TOP_SHIFT_UP: stretchStackTopShiftUp
0099  * @HB_OT_MATH_CONSTANT_STRETCH_STACK_BOTTOM_SHIFT_DOWN: stretchStackBottomShiftDown
0100  * @HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_ABOVE_MIN: stretchStackGapAboveMin
0101  * @HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_BELOW_MIN: stretchStackGapBelowMin
0102  * @HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_SHIFT_UP: fractionNumeratorShiftUp
0103  * @HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_DISPLAY_STYLE_SHIFT_UP: fractionNumeratorDisplayStyleShiftUp
0104  * @HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_SHIFT_DOWN: fractionDenominatorShiftDown
0105  * @HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_DISPLAY_STYLE_SHIFT_DOWN: fractionDenominatorDisplayStyleShiftDown
0106  * @HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_GAP_MIN: fractionNumeratorGapMin
0107  * @HB_OT_MATH_CONSTANT_FRACTION_NUM_DISPLAY_STYLE_GAP_MIN: fractionNumDisplayStyleGapMin
0108  * @HB_OT_MATH_CONSTANT_FRACTION_RULE_THICKNESS: fractionRuleThickness
0109  * @HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_GAP_MIN: fractionDenominatorGapMin
0110  * @HB_OT_MATH_CONSTANT_FRACTION_DENOM_DISPLAY_STYLE_GAP_MIN: fractionDenomDisplayStyleGapMin
0111  * @HB_OT_MATH_CONSTANT_SKEWED_FRACTION_HORIZONTAL_GAP: skewedFractionHorizontalGap
0112  * @HB_OT_MATH_CONSTANT_SKEWED_FRACTION_VERTICAL_GAP: skewedFractionVerticalGap
0113  * @HB_OT_MATH_CONSTANT_OVERBAR_VERTICAL_GAP: overbarVerticalGap
0114  * @HB_OT_MATH_CONSTANT_OVERBAR_RULE_THICKNESS: overbarRuleThickness
0115  * @HB_OT_MATH_CONSTANT_OVERBAR_EXTRA_ASCENDER: overbarExtraAscender
0116  * @HB_OT_MATH_CONSTANT_UNDERBAR_VERTICAL_GAP: underbarVerticalGap
0117  * @HB_OT_MATH_CONSTANT_UNDERBAR_RULE_THICKNESS: underbarRuleThickness
0118  * @HB_OT_MATH_CONSTANT_UNDERBAR_EXTRA_DESCENDER: underbarExtraDescender
0119  * @HB_OT_MATH_CONSTANT_RADICAL_VERTICAL_GAP: radicalVerticalGap
0120  * @HB_OT_MATH_CONSTANT_RADICAL_DISPLAY_STYLE_VERTICAL_GAP: radicalDisplayStyleVerticalGap
0121  * @HB_OT_MATH_CONSTANT_RADICAL_RULE_THICKNESS: radicalRuleThickness
0122  * @HB_OT_MATH_CONSTANT_RADICAL_EXTRA_ASCENDER: radicalExtraAscender
0123  * @HB_OT_MATH_CONSTANT_RADICAL_KERN_BEFORE_DEGREE: radicalKernBeforeDegree
0124  * @HB_OT_MATH_CONSTANT_RADICAL_KERN_AFTER_DEGREE: radicalKernAfterDegree
0125  * @HB_OT_MATH_CONSTANT_RADICAL_DEGREE_BOTTOM_RAISE_PERCENT: radicalDegreeBottomRaisePercent
0126  *
0127  * The 'MATH' table constants, refer to
0128  * [OpenType documentation](https://docs.microsoft.com/en-us/typography/opentype/spec/math#mathconstants-table)
0129  * For more explanations.
0130  *
0131  * Since: 1.3.3
0132  */
0133 typedef enum {
0134   HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN = 0,
0135   HB_OT_MATH_CONSTANT_SCRIPT_SCRIPT_PERCENT_SCALE_DOWN = 1,
0136   HB_OT_MATH_CONSTANT_DELIMITED_SUB_FORMULA_MIN_HEIGHT = 2,
0137   HB_OT_MATH_CONSTANT_DISPLAY_OPERATOR_MIN_HEIGHT = 3,
0138   HB_OT_MATH_CONSTANT_MATH_LEADING = 4,
0139   HB_OT_MATH_CONSTANT_AXIS_HEIGHT = 5,
0140   HB_OT_MATH_CONSTANT_ACCENT_BASE_HEIGHT = 6,
0141   HB_OT_MATH_CONSTANT_FLATTENED_ACCENT_BASE_HEIGHT = 7,
0142   HB_OT_MATH_CONSTANT_SUBSCRIPT_SHIFT_DOWN = 8,
0143   HB_OT_MATH_CONSTANT_SUBSCRIPT_TOP_MAX = 9,
0144   HB_OT_MATH_CONSTANT_SUBSCRIPT_BASELINE_DROP_MIN = 10,
0145   HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP = 11,
0146   HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP_CRAMPED = 12,
0147   HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MIN = 13,
0148   HB_OT_MATH_CONSTANT_SUPERSCRIPT_BASELINE_DROP_MAX = 14,
0149   HB_OT_MATH_CONSTANT_SUB_SUPERSCRIPT_GAP_MIN = 15,
0150   HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MAX_WITH_SUBSCRIPT = 16,
0151   HB_OT_MATH_CONSTANT_SPACE_AFTER_SCRIPT = 17,
0152   HB_OT_MATH_CONSTANT_UPPER_LIMIT_GAP_MIN = 18,
0153   HB_OT_MATH_CONSTANT_UPPER_LIMIT_BASELINE_RISE_MIN = 19,
0154   HB_OT_MATH_CONSTANT_LOWER_LIMIT_GAP_MIN = 20,
0155   HB_OT_MATH_CONSTANT_LOWER_LIMIT_BASELINE_DROP_MIN = 21,
0156   HB_OT_MATH_CONSTANT_STACK_TOP_SHIFT_UP = 22,
0157   HB_OT_MATH_CONSTANT_STACK_TOP_DISPLAY_STYLE_SHIFT_UP = 23,
0158   HB_OT_MATH_CONSTANT_STACK_BOTTOM_SHIFT_DOWN = 24,
0159   HB_OT_MATH_CONSTANT_STACK_BOTTOM_DISPLAY_STYLE_SHIFT_DOWN = 25,
0160   HB_OT_MATH_CONSTANT_STACK_GAP_MIN = 26,
0161   HB_OT_MATH_CONSTANT_STACK_DISPLAY_STYLE_GAP_MIN = 27,
0162   HB_OT_MATH_CONSTANT_STRETCH_STACK_TOP_SHIFT_UP = 28,
0163   HB_OT_MATH_CONSTANT_STRETCH_STACK_BOTTOM_SHIFT_DOWN = 29,
0164   HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_ABOVE_MIN = 30,
0165   HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_BELOW_MIN = 31,
0166   HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_SHIFT_UP = 32,
0167   HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_DISPLAY_STYLE_SHIFT_UP = 33,
0168   HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_SHIFT_DOWN = 34,
0169   HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_DISPLAY_STYLE_SHIFT_DOWN = 35,
0170   HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_GAP_MIN = 36,
0171   HB_OT_MATH_CONSTANT_FRACTION_NUM_DISPLAY_STYLE_GAP_MIN = 37,
0172   HB_OT_MATH_CONSTANT_FRACTION_RULE_THICKNESS = 38,
0173   HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_GAP_MIN = 39,
0174   HB_OT_MATH_CONSTANT_FRACTION_DENOM_DISPLAY_STYLE_GAP_MIN = 40,
0175   HB_OT_MATH_CONSTANT_SKEWED_FRACTION_HORIZONTAL_GAP = 41,
0176   HB_OT_MATH_CONSTANT_SKEWED_FRACTION_VERTICAL_GAP = 42,
0177   HB_OT_MATH_CONSTANT_OVERBAR_VERTICAL_GAP = 43,
0178   HB_OT_MATH_CONSTANT_OVERBAR_RULE_THICKNESS = 44,
0179   HB_OT_MATH_CONSTANT_OVERBAR_EXTRA_ASCENDER = 45,
0180   HB_OT_MATH_CONSTANT_UNDERBAR_VERTICAL_GAP = 46,
0181   HB_OT_MATH_CONSTANT_UNDERBAR_RULE_THICKNESS = 47,
0182   HB_OT_MATH_CONSTANT_UNDERBAR_EXTRA_DESCENDER = 48,
0183   HB_OT_MATH_CONSTANT_RADICAL_VERTICAL_GAP = 49,
0184   HB_OT_MATH_CONSTANT_RADICAL_DISPLAY_STYLE_VERTICAL_GAP = 50,
0185   HB_OT_MATH_CONSTANT_RADICAL_RULE_THICKNESS = 51,
0186   HB_OT_MATH_CONSTANT_RADICAL_EXTRA_ASCENDER = 52,
0187   HB_OT_MATH_CONSTANT_RADICAL_KERN_BEFORE_DEGREE = 53,
0188   HB_OT_MATH_CONSTANT_RADICAL_KERN_AFTER_DEGREE = 54,
0189   HB_OT_MATH_CONSTANT_RADICAL_DEGREE_BOTTOM_RAISE_PERCENT = 55
0190 } hb_ot_math_constant_t;
0191
0192 /**
0193  * hb_ot_math_kern_t:
0194  * @HB_OT_MATH_KERN_TOP_RIGHT: The top right corner of the glyph.
0195  * @HB_OT_MATH_KERN_TOP_LEFT: The top left corner of the glyph.
0196  * @HB_OT_MATH_KERN_BOTTOM_RIGHT: The bottom right corner of the glyph.
0197  * @HB_OT_MATH_KERN_BOTTOM_LEFT: The bottom left corner of the glyph.
0198  *
0199  * The math kerning-table types defined for the four corners
0200  * of a glyph.
0201  *
0202  * Since: 1.3.3
0203  */
0204 typedef enum {
0205   HB_OT_MATH_KERN_TOP_RIGHT = 0,
0206   HB_OT_MATH_KERN_TOP_LEFT = 1,
0207   HB_OT_MATH_KERN_BOTTOM_RIGHT = 2,
0208   HB_OT_MATH_KERN_BOTTOM_LEFT = 3
0209 } hb_ot_math_kern_t;
0210
0211 /**
0212  * hb_ot_math_kern_entry_t:
0213  * @max_correction_height: The maximum height at which this entry should be used
0214  * @kern_value: The kern value of the entry
0215  *
0216  * Data type to hold math kerning (cut-in) information for a glyph.
0217  *
0218  * Since: 3.4.0
0219  */
0220 typedef struct {
0221   hb_position_t max_correction_height;
0222   hb_position_t kern_value;
0223 } hb_ot_math_kern_entry_t;
0224
0225 /**
0226  * hb_ot_math_glyph_variant_t:
0227  * @glyph: The glyph index of the variant
0228  * @advance: The advance width of the variant
0229  *
0230  * Data type to hold math-variant information for a glyph.
0231  *
0232  * Since: 1.3.3
0233  */
0234 typedef struct hb_ot_math_glyph_variant_t {
0235   hb_codepoint_t glyph;
0236   hb_position_t advance;
0237 } hb_ot_math_glyph_variant_t;
0238
0239 /**
0240  * hb_ot_math_glyph_part_flags_t:
0241  * @HB_OT_MATH_GLYPH_PART_FLAG_EXTENDER: This is an extender glyph part that
0242  * can be repeated to reach the desired length.
0243  *
0244  * Flags for math glyph parts.
0245  *
0246  * Since: 1.3.3
0247  */
0248 typedef enum { /*< flags >*/
0249   HB_OT_MATH_GLYPH_PART_FLAG_EXTENDER   = 0x00000001u  /* Extender glyph */
0250 } hb_ot_math_glyph_part_flags_t;
0251
0252 /**
0253  * hb_ot_math_glyph_part_t:
0254  * @glyph: The glyph index of the variant part
0255  * @start_connector_length: The length of the connector on the starting side of the variant part
0256  * @end_connector_length: The length of the connector on the ending side of the variant part
0257  * @full_advance: The total advance of the part
0258  * @flags: #hb_ot_math_glyph_part_flags_t flags for the part
0259  *
0260  * Data type to hold information for a "part" component of a math-variant glyph.
0261  * Large variants for stretchable math glyphs (such as parentheses) can be constructed
0262  * on the fly from parts.
0263  *
0264  * Since: 1.3.3
0265  */
0266 typedef struct hb_ot_math_glyph_part_t {
0267   hb_codepoint_t glyph;
0268   hb_position_t start_connector_length;
0269   hb_position_t end_connector_length;
0270   hb_position_t full_advance;
0271   hb_ot_math_glyph_part_flags_t flags;
0272 } hb_ot_math_glyph_part_t;
0273
0274 /* Methods */
0275
0276 HB_EXTERN hb_bool_t
0277 hb_ot_math_has_data (hb_face_t *face);
0278
0279 HB_EXTERN hb_position_t
0280 hb_ot_math_get_constant (hb_font_t *font,
0281              hb_ot_math_constant_t constant);
0282
0283 HB_EXTERN hb_position_t
0284 hb_ot_math_get_glyph_italics_correction (hb_font_t *font,
0285                      hb_codepoint_t glyph);
0286
0287 HB_EXTERN hb_position_t
0288 hb_ot_math_get_glyph_top_accent_attachment (hb_font_t *font,
0289                         hb_codepoint_t glyph);
0290
0291 HB_EXTERN hb_bool_t
0292 hb_ot_math_is_glyph_extended_shape (hb_face_t *face,
0293                     hb_codepoint_t glyph);
0294
0295 HB_EXTERN hb_position_t
0296 hb_ot_math_get_glyph_kerning (hb_font_t *font,
0297                   hb_codepoint_t glyph,
0298                   hb_ot_math_kern_t kern,
0299                   hb_position_t correction_height);
0300
0301 HB_EXTERN unsigned int
0302 hb_ot_math_get_glyph_kernings (hb_font_t *font,
0303                    hb_codepoint_t glyph,
0304                    hb_ot_math_kern_t kern,
0305                    unsigned int start_offset,
0306                    unsigned int *entries_count, /* IN/OUT */
0307                    hb_ot_math_kern_entry_t *kern_entries /* OUT */);
0308
0309 HB_EXTERN unsigned int
0310 hb_ot_math_get_glyph_variants (hb_font_t *font,
0311                    hb_codepoint_t glyph,
0312                    hb_direction_t direction,
0313                    unsigned int start_offset,
0314                    unsigned int *variants_count, /* IN/OUT */
0315                    hb_ot_math_glyph_variant_t *variants /* OUT */);
0316
0317 HB_EXTERN hb_position_t
0318 hb_ot_math_get_min_connector_overlap (hb_font_t *font,
0319                       hb_direction_t direction);
0320
0321 HB_EXTERN unsigned int
0322 hb_ot_math_get_glyph_assembly (hb_font_t *font,
0323                    hb_codepoint_t glyph,
0324                    hb_direction_t direction,
0325                    unsigned int start_offset,
0326                    unsigned int *parts_count, /* IN/OUT */
0327                    hb_ot_math_glyph_part_t *parts, /* OUT */
0328                    hb_position_t *italics_correction /* OUT */);
0329
0330
0331 HB_END_DECLS
0332
0333 #endif /* HB_OT_MATH_H */