src/hb-ot-math.h

   1 /*
   2  * Copyright © 2016  Igalia S.L.
   3  *
   4  *  This is part of HarfBuzz, a text shaping library.
   5  *
   6  * Permission is hereby granted, without written agreement and without
   7  * license or royalty fees, to use, copy, modify, and distribute this
   8  * software and its documentation for any purpose, provided that the
   9  * above copyright notice and the following two paragraphs appear in
  10  * all copies of this software.
  11  *
  12  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  13  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  14  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  15  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  16  * DAMAGE.
  17  *
  18  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  19  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  20  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  21  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  22  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  23  *
  24  * Igalia Author(s): Frédéric Wang
  25  */
  26
  27 #if !defined(HB_OT_H_IN) && !defined(HB_NO_SINGLE_HEADER_ERROR)
  28 #error "Include <hb-ot.h> instead."
  29 #endif
  30
  31 #ifndef HB_OT_MATH_H
  32 #define HB_OT_MATH_H
  33
  34 #include "hb.h"
  35
  36 HB_BEGIN_DECLS
  37
  38
  39 /*
  40  * MATH
  41  */
  42
  43 /**
  44  * HB_OT_TAG_MATH:
  45  *
  46  * OpenType [Mathematical Typesetting Table](https://docs.microsoft.com/en-us/typography/opentype/spec/math).
  47  *
  48  * Since: 1.3.3
  49  */
  50 #define HB_OT_TAG_MATH HB_TAG('M','A','T','H')
  51
  52 /**
  53  * HB_OT_TAG_MATH_SCRIPT:
  54  *
  55  * OpenType script tag, `math`, for features specific to math shaping.
  56  *
  57  * <note>#HB_OT_TAG_MATH_SCRIPT is not a valid #hb_script_t and should only be
  58  * used with functions that accept raw OpenType script tags, such as
  59  * #hb_ot_layout_collect_features. In other cases, #HB_SCRIPT_MATH should be
  60  * used instead.</note>
  61  *
  62  * Since: 3.4.0
  63  */
  64 #define HB_OT_TAG_MATH_SCRIPT HB_TAG('m','a','t','h')
  65
  66 /* Types */
  67
  68 /**
  69  * hb_ot_math_constant_t:
  70  * @HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN: scriptPercentScaleDown
  71  * @HB_OT_MATH_CONSTANT_SCRIPT_SCRIPT_PERCENT_SCALE_DOWN: scriptScriptPercentScaleDown
  72  * @HB_OT_MATH_CONSTANT_DELIMITED_SUB_FORMULA_MIN_HEIGHT: delimitedSubFormulaMinHeight
  73  * @HB_OT_MATH_CONSTANT_DISPLAY_OPERATOR_MIN_HEIGHT: displayOperatorMinHeight
  74  * @HB_OT_MATH_CONSTANT_MATH_LEADING: mathLeading
  75  * @HB_OT_MATH_CONSTANT_AXIS_HEIGHT: axisHeight
  76  * @HB_OT_MATH_CONSTANT_ACCENT_BASE_HEIGHT: accentBaseHeight
  77  * @HB_OT_MATH_CONSTANT_FLATTENED_ACCENT_BASE_HEIGHT: flattenedAccentBaseHeight
  78  * @HB_OT_MATH_CONSTANT_SUBSCRIPT_SHIFT_DOWN: subscriptShiftDown
  79  * @HB_OT_MATH_CONSTANT_SUBSCRIPT_TOP_MAX: subscriptTopMax
  80  * @HB_OT_MATH_CONSTANT_SUBSCRIPT_BASELINE_DROP_MIN: subscriptBaselineDropMin
  81  * @HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP: superscriptShiftUp
  82  * @HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP_CRAMPED: superscriptShiftUpCramped
  83  * @HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MIN: superscriptBottomMin
  84  * @HB_OT_MATH_CONSTANT_SUPERSCRIPT_BASELINE_DROP_MAX: superscriptBaselineDropMax
  85  * @HB_OT_MATH_CONSTANT_SUB_SUPERSCRIPT_GAP_MIN: subSuperscriptGapMin
  86  * @HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MAX_WITH_SUBSCRIPT: superscriptBottomMaxWithSubscript
  87  * @HB_OT_MATH_CONSTANT_SPACE_AFTER_SCRIPT: spaceAfterScript
  88  * @HB_OT_MATH_CONSTANT_UPPER_LIMIT_GAP_MIN: upperLimitGapMin
  89  * @HB_OT_MATH_CONSTANT_UPPER_LIMIT_BASELINE_RISE_MIN: upperLimitBaselineRiseMin
  90  * @HB_OT_MATH_CONSTANT_LOWER_LIMIT_GAP_MIN: lowerLimitGapMin
  91  * @HB_OT_MATH_CONSTANT_LOWER_LIMIT_BASELINE_DROP_MIN: lowerLimitBaselineDropMin
  92  * @HB_OT_MATH_CONSTANT_STACK_TOP_SHIFT_UP: stackTopShiftUp
  93  * @HB_OT_MATH_CONSTANT_STACK_TOP_DISPLAY_STYLE_SHIFT_UP: stackTopDisplayStyleShiftUp
  94  * @HB_OT_MATH_CONSTANT_STACK_BOTTOM_SHIFT_DOWN: stackBottomShiftDown
  95  * @HB_OT_MATH_CONSTANT_STACK_BOTTOM_DISPLAY_STYLE_SHIFT_DOWN: stackBottomDisplayStyleShiftDown
  96  * @HB_OT_MATH_CONSTANT_STACK_GAP_MIN: stackGapMin
  97  * @HB_OT_MATH_CONSTANT_STACK_DISPLAY_STYLE_GAP_MIN: stackDisplayStyleGapMin
  98  * @HB_OT_MATH_CONSTANT_STRETCH_STACK_TOP_SHIFT_UP: stretchStackTopShiftUp
  99  * @HB_OT_MATH_CONSTANT_STRETCH_STACK_BOTTOM_SHIFT_DOWN: stretchStackBottomShiftDown
 100  * @HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_ABOVE_MIN: stretchStackGapAboveMin
 101  * @HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_BELOW_MIN: stretchStackGapBelowMin
 102  * @HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_SHIFT_UP: fractionNumeratorShiftUp
 103  * @HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_DISPLAY_STYLE_SHIFT_UP: fractionNumeratorDisplayStyleShiftUp
 104  * @HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_SHIFT_DOWN: fractionDenominatorShiftDown
 105  * @HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_DISPLAY_STYLE_SHIFT_DOWN: fractionDenominatorDisplayStyleShiftDown
 106  * @HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_GAP_MIN: fractionNumeratorGapMin
 107  * @HB_OT_MATH_CONSTANT_FRACTION_NUM_DISPLAY_STYLE_GAP_MIN: fractionNumDisplayStyleGapMin
 108  * @HB_OT_MATH_CONSTANT_FRACTION_RULE_THICKNESS: fractionRuleThickness
 109  * @HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_GAP_MIN: fractionDenominatorGapMin
 110  * @HB_OT_MATH_CONSTANT_FRACTION_DENOM_DISPLAY_STYLE_GAP_MIN: fractionDenomDisplayStyleGapMin
 111  * @HB_OT_MATH_CONSTANT_SKEWED_FRACTION_HORIZONTAL_GAP: skewedFractionHorizontalGap
 112  * @HB_OT_MATH_CONSTANT_SKEWED_FRACTION_VERTICAL_GAP: skewedFractionVerticalGap
 113  * @HB_OT_MATH_CONSTANT_OVERBAR_VERTICAL_GAP: overbarVerticalGap
 114  * @HB_OT_MATH_CONSTANT_OVERBAR_RULE_THICKNESS: overbarRuleThickness
 115  * @HB_OT_MATH_CONSTANT_OVERBAR_EXTRA_ASCENDER: overbarExtraAscender
 116  * @HB_OT_MATH_CONSTANT_UNDERBAR_VERTICAL_GAP: underbarVerticalGap
 117  * @HB_OT_MATH_CONSTANT_UNDERBAR_RULE_THICKNESS: underbarRuleThickness
 118  * @HB_OT_MATH_CONSTANT_UNDERBAR_EXTRA_DESCENDER: underbarExtraDescender
 119  * @HB_OT_MATH_CONSTANT_RADICAL_VERTICAL_GAP: radicalVerticalGap
 120  * @HB_OT_MATH_CONSTANT_RADICAL_DISPLAY_STYLE_VERTICAL_GAP: radicalDisplayStyleVerticalGap
 121  * @HB_OT_MATH_CONSTANT_RADICAL_RULE_THICKNESS: radicalRuleThickness
 122  * @HB_OT_MATH_CONSTANT_RADICAL_EXTRA_ASCENDER: radicalExtraAscender
 123  * @HB_OT_MATH_CONSTANT_RADICAL_KERN_BEFORE_DEGREE: radicalKernBeforeDegree
 124  * @HB_OT_MATH_CONSTANT_RADICAL_KERN_AFTER_DEGREE: radicalKernAfterDegree
 125  * @HB_OT_MATH_CONSTANT_RADICAL_DEGREE_BOTTOM_RAISE_PERCENT: radicalDegreeBottomRaisePercent
 126  *
 127  * The 'MATH' table constants, refer to
 128  * [OpenType documentation](https://docs.microsoft.com/en-us/typography/opentype/spec/math#mathconstants-table)
 129  * For more explanations.
 130  *
 131  * Since: 1.3.3
 132  */
 133 typedef enum {
 134   HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN = 0,
 135   HB_OT_MATH_CONSTANT_SCRIPT_SCRIPT_PERCENT_SCALE_DOWN = 1,
 136   HB_OT_MATH_CONSTANT_DELIMITED_SUB_FORMULA_MIN_HEIGHT = 2,
 137   HB_OT_MATH_CONSTANT_DISPLAY_OPERATOR_MIN_HEIGHT = 3,
 138   HB_OT_MATH_CONSTANT_MATH_LEADING = 4,
 139   HB_OT_MATH_CONSTANT_AXIS_HEIGHT = 5,
 140   HB_OT_MATH_CONSTANT_ACCENT_BASE_HEIGHT = 6,
 141   HB_OT_MATH_CONSTANT_FLATTENED_ACCENT_BASE_HEIGHT = 7,
 142   HB_OT_MATH_CONSTANT_SUBSCRIPT_SHIFT_DOWN = 8,
 143   HB_OT_MATH_CONSTANT_SUBSCRIPT_TOP_MAX = 9,
 144   HB_OT_MATH_CONSTANT_SUBSCRIPT_BASELINE_DROP_MIN = 10,
 145   HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP = 11,
 146   HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP_CRAMPED = 12,
 147   HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MIN = 13,
 148   HB_OT_MATH_CONSTANT_SUPERSCRIPT_BASELINE_DROP_MAX = 14,
 149   HB_OT_MATH_CONSTANT_SUB_SUPERSCRIPT_GAP_MIN = 15,
 150   HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MAX_WITH_SUBSCRIPT = 16,
 151   HB_OT_MATH_CONSTANT_SPACE_AFTER_SCRIPT = 17,
 152   HB_OT_MATH_CONSTANT_UPPER_LIMIT_GAP_MIN = 18,
 153   HB_OT_MATH_CONSTANT_UPPER_LIMIT_BASELINE_RISE_MIN = 19,
 154   HB_OT_MATH_CONSTANT_LOWER_LIMIT_GAP_MIN = 20,
 155   HB_OT_MATH_CONSTANT_LOWER_LIMIT_BASELINE_DROP_MIN = 21,
 156   HB_OT_MATH_CONSTANT_STACK_TOP_SHIFT_UP = 22,
 157   HB_OT_MATH_CONSTANT_STACK_TOP_DISPLAY_STYLE_SHIFT_UP = 23,
 158   HB_OT_MATH_CONSTANT_STACK_BOTTOM_SHIFT_DOWN = 24,
 159   HB_OT_MATH_CONSTANT_STACK_BOTTOM_DISPLAY_STYLE_SHIFT_DOWN = 25,
 160   HB_OT_MATH_CONSTANT_STACK_GAP_MIN = 26,
 161   HB_OT_MATH_CONSTANT_STACK_DISPLAY_STYLE_GAP_MIN = 27,
 162   HB_OT_MATH_CONSTANT_STRETCH_STACK_TOP_SHIFT_UP = 28,
 163   HB_OT_MATH_CONSTANT_STRETCH_STACK_BOTTOM_SHIFT_DOWN = 29,
 164   HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_ABOVE_MIN = 30,
 165   HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_BELOW_MIN = 31,
 166   HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_SHIFT_UP = 32,
 167   HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_DISPLAY_STYLE_SHIFT_UP = 33,
 168   HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_SHIFT_DOWN = 34,
 169   HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_DISPLAY_STYLE_SHIFT_DOWN = 35,
 170   HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_GAP_MIN = 36,
 171   HB_OT_MATH_CONSTANT_FRACTION_NUM_DISPLAY_STYLE_GAP_MIN = 37,
 172   HB_OT_MATH_CONSTANT_FRACTION_RULE_THICKNESS = 38,
 173   HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_GAP_MIN = 39,
 174   HB_OT_MATH_CONSTANT_FRACTION_DENOM_DISPLAY_STYLE_GAP_MIN = 40,
 175   HB_OT_MATH_CONSTANT_SKEWED_FRACTION_HORIZONTAL_GAP = 41,
 176   HB_OT_MATH_CONSTANT_SKEWED_FRACTION_VERTICAL_GAP = 42,
 177   HB_OT_MATH_CONSTANT_OVERBAR_VERTICAL_GAP = 43,
 178   HB_OT_MATH_CONSTANT_OVERBAR_RULE_THICKNESS = 44,
 179   HB_OT_MATH_CONSTANT_OVERBAR_EXTRA_ASCENDER = 45,
 180   HB_OT_MATH_CONSTANT_UNDERBAR_VERTICAL_GAP = 46,
 181   HB_OT_MATH_CONSTANT_UNDERBAR_RULE_THICKNESS = 47,
 182   HB_OT_MATH_CONSTANT_UNDERBAR_EXTRA_DESCENDER = 48,
 183   HB_OT_MATH_CONSTANT_RADICAL_VERTICAL_GAP = 49,
 184   HB_OT_MATH_CONSTANT_RADICAL_DISPLAY_STYLE_VERTICAL_GAP = 50,
 185   HB_OT_MATH_CONSTANT_RADICAL_RULE_THICKNESS = 51,
 186   HB_OT_MATH_CONSTANT_RADICAL_EXTRA_ASCENDER = 52,
 187   HB_OT_MATH_CONSTANT_RADICAL_KERN_BEFORE_DEGREE = 53,
 188   HB_OT_MATH_CONSTANT_RADICAL_KERN_AFTER_DEGREE = 54,
 189   HB_OT_MATH_CONSTANT_RADICAL_DEGREE_BOTTOM_RAISE_PERCENT = 55
 190 } hb_ot_math_constant_t;
 191
 192 /**
 193  * hb_ot_math_kern_t:
 194  * @HB_OT_MATH_KERN_TOP_RIGHT: The top right corner of the glyph.
 195  * @HB_OT_MATH_KERN_TOP_LEFT: The top left corner of the glyph.
 196  * @HB_OT_MATH_KERN_BOTTOM_RIGHT: The bottom right corner of the glyph.
 197  * @HB_OT_MATH_KERN_BOTTOM_LEFT: The bottom left corner of the glyph.
 198  *
 199  * The math kerning-table types defined for the four corners
 200  * of a glyph.
 201  *
 202  * Since: 1.3.3
 203  */
 204 typedef enum {
 205   HB_OT_MATH_KERN_TOP_RIGHT = 0,
 206   HB_OT_MATH_KERN_TOP_LEFT = 1,
 207   HB_OT_MATH_KERN_BOTTOM_RIGHT = 2,
 208   HB_OT_MATH_KERN_BOTTOM_LEFT = 3
 209 } hb_ot_math_kern_t;
 210
 211 /**
 212  * hb_ot_math_kern_entry_t:
 213  * @max_correction_height: The maximum height at which this entry should be used
 214  * @kern_value: The kern value of the entry
 215  *
 216  * Data type to hold math kerning (cut-in) information for a glyph.
 217  *
 218  * Since: 3.4.0
 219  */
 220 typedef struct {
 221   hb_position_t max_correction_height;
 222   hb_position_t kern_value;
 223 } hb_ot_math_kern_entry_t;
 224
 225 /**
 226  * hb_ot_math_glyph_variant_t:
 227  * @glyph: The glyph index of the variant
 228  * @advance: The advance width of the variant
 229  *
 230  * Data type to hold math-variant information for a glyph.
 231  *
 232  * Since: 1.3.3
 233  */
 234 typedef struct hb_ot_math_glyph_variant_t {
 235   hb_codepoint_t glyph;
 236   hb_position_t advance;
 237 } hb_ot_math_glyph_variant_t;
 238
 239 /**
 240  * hb_ot_math_glyph_part_flags_t:
 241  * @HB_OT_MATH_GLYPH_PART_FLAG_EXTENDER: This is an extender glyph part that
 242  * can be repeated to reach the desired length.
 243  *
 244  * Flags for math glyph parts.
 245  *
 246  * Since: 1.3.3
 247  */
 248 typedef enum { /*< flags >*/
 249   HB_OT_MATH_GLYPH_PART_FLAG_EXTENDER   = 0x00000001u  /* Extender glyph */
 250 } hb_ot_math_glyph_part_flags_t;
 251
 252 /**
 253  * hb_ot_math_glyph_part_t:
 254  * @glyph: The glyph index of the variant part
 255  * @start_connector_length: The length of the connector on the starting side of the variant part
 256  * @end_connector_length: The length of the connector on the ending side of the variant part
 257  * @full_advance: The total advance of the part
 258  * @flags: #hb_ot_math_glyph_part_flags_t flags for the part
 259  *
 260  * Data type to hold information for a "part" component of a math-variant glyph.
 261  * Large variants for stretchable math glyphs (such as parentheses) can be constructed
 262  * on the fly from parts.
 263  *
 264  * Since: 1.3.3
 265  */
 266 typedef struct hb_ot_math_glyph_part_t {
 267   hb_codepoint_t glyph;
 268   hb_position_t start_connector_length;
 269   hb_position_t end_connector_length;
 270   hb_position_t full_advance;
 271   hb_ot_math_glyph_part_flags_t flags;
 272 } hb_ot_math_glyph_part_t;
 273
 274 /* Methods */
 275
 276 HB_EXTERN hb_bool_t
 277 hb_ot_math_has_data (hb_face_t *face);
 278
 279 HB_EXTERN hb_position_t
 280 hb_ot_math_get_constant (hb_font_t *font,
 281                          hb_ot_math_constant_t constant);
 282
 283 HB_EXTERN hb_position_t
 284 hb_ot_math_get_glyph_italics_correction (hb_font_t *font,
 285                                          hb_codepoint_t glyph);
 286
 287 HB_EXTERN hb_position_t
 288 hb_ot_math_get_glyph_top_accent_attachment (hb_font_t *font,
 289                                             hb_codepoint_t glyph);
 290
 291 HB_EXTERN hb_bool_t
 292 hb_ot_math_is_glyph_extended_shape (hb_face_t *face,
 293                                     hb_codepoint_t glyph);
 294
 295 HB_EXTERN hb_position_t
 296 hb_ot_math_get_glyph_kerning (hb_font_t *font,
 297                               hb_codepoint_t glyph,
 298                               hb_ot_math_kern_t kern,
 299                               hb_position_t correction_height);
 300
 301 HB_EXTERN unsigned int
 302 hb_ot_math_get_glyph_kernings (hb_font_t *font,
 303                                hb_codepoint_t glyph,
 304                                hb_ot_math_kern_t kern,
 305                                unsigned int start_offset,
 306                                unsigned int *entries_count, /* IN/OUT */
 307                                hb_ot_math_kern_entry_t *kern_entries /* OUT */);
 308
 309 HB_EXTERN unsigned int
 310 hb_ot_math_get_glyph_variants (hb_font_t *font,
 311                                hb_codepoint_t glyph,
 312                                hb_direction_t direction,
 313                                unsigned int start_offset,
 314                                unsigned int *variants_count, /* IN/OUT */
 315                                hb_ot_math_glyph_variant_t *variants /* OUT */);
 316
 317 HB_EXTERN hb_position_t
 318 hb_ot_math_get_min_connector_overlap (hb_font_t *font,
 319                                       hb_direction_t direction);
 320
 321 HB_EXTERN unsigned int
 322 hb_ot_math_get_glyph_assembly (hb_font_t *font,
 323                                hb_codepoint_t glyph,
 324                                hb_direction_t direction,
 325                                unsigned int start_offset,
 326                                unsigned int *parts_count, /* IN/OUT */
 327                                hb_ot_math_glyph_part_t *parts, /* OUT */
 328                                hb_position_t *italics_correction /* OUT */);
 329
 330
 331 HB_END_DECLS
 332
 333 #endif /* HB_OT_MATH_H */