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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 #ifndef HB_OT_H_IN
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 #define HB_OT_TAG_MATH HB_TAG('M','A','T','H')
44 
45 /* Use with hb_buffer_set_script() for math shaping. */
46 #define HB_OT_MATH_SCRIPT HB_TAG('m','a','t','h')
47 
48 /* Types */
49 
50 /**
51  * hb_ot_math_constant_t:
52  *
53  * The 'MATH' table constants specified at
54  * https://docs.microsoft.com/en-us/typography/opentype/spec/math
55  *
56  * Since: 1.3.3
57  */
58 typedef enum {
59   HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN = 0,
60   HB_OT_MATH_CONSTANT_SCRIPT_SCRIPT_PERCENT_SCALE_DOWN = 1,
61   HB_OT_MATH_CONSTANT_DELIMITED_SUB_FORMULA_MIN_HEIGHT = 2,
62   HB_OT_MATH_CONSTANT_DISPLAY_OPERATOR_MIN_HEIGHT = 3,
63   HB_OT_MATH_CONSTANT_MATH_LEADING = 4,
64   HB_OT_MATH_CONSTANT_AXIS_HEIGHT = 5,
65   HB_OT_MATH_CONSTANT_ACCENT_BASE_HEIGHT = 6,
66   HB_OT_MATH_CONSTANT_FLATTENED_ACCENT_BASE_HEIGHT = 7,
67   HB_OT_MATH_CONSTANT_SUBSCRIPT_SHIFT_DOWN = 8,
68   HB_OT_MATH_CONSTANT_SUBSCRIPT_TOP_MAX = 9,
69   HB_OT_MATH_CONSTANT_SUBSCRIPT_BASELINE_DROP_MIN = 10,
70   HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP = 11,
71   HB_OT_MATH_CONSTANT_SUPERSCRIPT_SHIFT_UP_CRAMPED = 12,
72   HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MIN = 13,
73   HB_OT_MATH_CONSTANT_SUPERSCRIPT_BASELINE_DROP_MAX = 14,
74   HB_OT_MATH_CONSTANT_SUB_SUPERSCRIPT_GAP_MIN = 15,
75   HB_OT_MATH_CONSTANT_SUPERSCRIPT_BOTTOM_MAX_WITH_SUBSCRIPT = 16,
76   HB_OT_MATH_CONSTANT_SPACE_AFTER_SCRIPT = 17,
77   HB_OT_MATH_CONSTANT_UPPER_LIMIT_GAP_MIN = 18,
78   HB_OT_MATH_CONSTANT_UPPER_LIMIT_BASELINE_RISE_MIN = 19,
79   HB_OT_MATH_CONSTANT_LOWER_LIMIT_GAP_MIN = 20,
80   HB_OT_MATH_CONSTANT_LOWER_LIMIT_BASELINE_DROP_MIN = 21,
81   HB_OT_MATH_CONSTANT_STACK_TOP_SHIFT_UP = 22,
82   HB_OT_MATH_CONSTANT_STACK_TOP_DISPLAY_STYLE_SHIFT_UP = 23,
83   HB_OT_MATH_CONSTANT_STACK_BOTTOM_SHIFT_DOWN = 24,
84   HB_OT_MATH_CONSTANT_STACK_BOTTOM_DISPLAY_STYLE_SHIFT_DOWN = 25,
85   HB_OT_MATH_CONSTANT_STACK_GAP_MIN = 26,
86   HB_OT_MATH_CONSTANT_STACK_DISPLAY_STYLE_GAP_MIN = 27,
87   HB_OT_MATH_CONSTANT_STRETCH_STACK_TOP_SHIFT_UP = 28,
88   HB_OT_MATH_CONSTANT_STRETCH_STACK_BOTTOM_SHIFT_DOWN = 29,
89   HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_ABOVE_MIN = 30,
90   HB_OT_MATH_CONSTANT_STRETCH_STACK_GAP_BELOW_MIN = 31,
91   HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_SHIFT_UP = 32,
92   HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_DISPLAY_STYLE_SHIFT_UP = 33,
93   HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_SHIFT_DOWN = 34,
94   HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_DISPLAY_STYLE_SHIFT_DOWN = 35,
95   HB_OT_MATH_CONSTANT_FRACTION_NUMERATOR_GAP_MIN = 36,
96   HB_OT_MATH_CONSTANT_FRACTION_NUM_DISPLAY_STYLE_GAP_MIN = 37,
97   HB_OT_MATH_CONSTANT_FRACTION_RULE_THICKNESS = 38,
98   HB_OT_MATH_CONSTANT_FRACTION_DENOMINATOR_GAP_MIN = 39,
99   HB_OT_MATH_CONSTANT_FRACTION_DENOM_DISPLAY_STYLE_GAP_MIN = 40,
100   HB_OT_MATH_CONSTANT_SKEWED_FRACTION_HORIZONTAL_GAP = 41,
101   HB_OT_MATH_CONSTANT_SKEWED_FRACTION_VERTICAL_GAP = 42,
102   HB_OT_MATH_CONSTANT_OVERBAR_VERTICAL_GAP = 43,
103   HB_OT_MATH_CONSTANT_OVERBAR_RULE_THICKNESS = 44,
104   HB_OT_MATH_CONSTANT_OVERBAR_EXTRA_ASCENDER = 45,
105   HB_OT_MATH_CONSTANT_UNDERBAR_VERTICAL_GAP = 46,
106   HB_OT_MATH_CONSTANT_UNDERBAR_RULE_THICKNESS = 47,
107   HB_OT_MATH_CONSTANT_UNDERBAR_EXTRA_DESCENDER = 48,
108   HB_OT_MATH_CONSTANT_RADICAL_VERTICAL_GAP = 49,
109   HB_OT_MATH_CONSTANT_RADICAL_DISPLAY_STYLE_VERTICAL_GAP = 50,
110   HB_OT_MATH_CONSTANT_RADICAL_RULE_THICKNESS = 51,
111   HB_OT_MATH_CONSTANT_RADICAL_EXTRA_ASCENDER = 52,
112   HB_OT_MATH_CONSTANT_RADICAL_KERN_BEFORE_DEGREE = 53,
113   HB_OT_MATH_CONSTANT_RADICAL_KERN_AFTER_DEGREE = 54,
114   HB_OT_MATH_CONSTANT_RADICAL_DEGREE_BOTTOM_RAISE_PERCENT = 55
115 } hb_ot_math_constant_t;
116 
117 /**
118  * hb_ot_math_kern_t:
119  *
120  * The math kerning-table types defined for the four corners
121  * of a glyph.
122  *
123  * Since: 1.3.3
124  */
125 typedef enum {
126   HB_OT_MATH_KERN_TOP_RIGHT = 0,
127   HB_OT_MATH_KERN_TOP_LEFT = 1,
128   HB_OT_MATH_KERN_BOTTOM_RIGHT = 2,
129   HB_OT_MATH_KERN_BOTTOM_LEFT = 3
130 } hb_ot_math_kern_t;
131 
132 /**
133  * hb_ot_math_glyph_variant_t:
134  * @glyph: The glyph index of the variant
135  * @advance: The advance width of the variant
136  *
137  * Data type to hold math-variant information for a glyph.
138  *
139  * Since: 1.3.3
140  */
141 typedef struct hb_ot_math_glyph_variant_t {
142   hb_codepoint_t glyph;
143   hb_position_t advance;
144 } hb_ot_math_glyph_variant_t;
145 
146 /**
147  * hb_ot_math_glyph_part_flags_t:
148  *
149  * Flags for math glyph parts.
150  *
151  * Since: 1.3.3
152  */
153 typedef enum { /*< flags >*/
154   HB_OT_MATH_GLYPH_PART_FLAG_EXTENDER	= 0x00000001u  /* Extender glyph */
155 } hb_ot_math_glyph_part_flags_t;
156 
157 /**
158  * hb_ot_math_glyph_part_t:
159  * @glyph: The glyph index of the variant part
160  * @start_connector_length: The length of the connector on the starting side of the variant part
161  * @end_connector_length: The length of the connector on the ending side of the variant part
162  * @full_advance: The total advance of the part
163  * @flags: #hb_ot_math_glyph_part_flags_t flags for the part
164  *
165  * Data type to hold information for a "part" component of a math-variant glyph.
166  * Large variants for stretchable math glyphs (such as parentheses) can be constructed
167  * on the fly from parts.
168  *
169  * Since: 1.3.3
170  */
171 typedef struct hb_ot_math_glyph_part_t {
172   hb_codepoint_t glyph;
173   hb_position_t start_connector_length;
174   hb_position_t end_connector_length;
175   hb_position_t full_advance;
176   hb_ot_math_glyph_part_flags_t flags;
177 } hb_ot_math_glyph_part_t;
178 
179 /* Methods */
180 
181 HB_EXTERN hb_bool_t
182 hb_ot_math_has_data (hb_face_t *face);
183 
184 HB_EXTERN hb_position_t
185 hb_ot_math_get_constant (hb_font_t *font,
186 			 hb_ot_math_constant_t constant);
187 
188 HB_EXTERN hb_position_t
189 hb_ot_math_get_glyph_italics_correction (hb_font_t *font,
190 					 hb_codepoint_t glyph);
191 
192 HB_EXTERN hb_position_t
193 hb_ot_math_get_glyph_top_accent_attachment (hb_font_t *font,
194 					    hb_codepoint_t glyph);
195 
196 HB_EXTERN hb_bool_t
197 hb_ot_math_is_glyph_extended_shape (hb_face_t *face,
198 				    hb_codepoint_t glyph);
199 
200 HB_EXTERN hb_position_t
201 hb_ot_math_get_glyph_kerning (hb_font_t *font,
202 			      hb_codepoint_t glyph,
203 			      hb_ot_math_kern_t kern,
204 			      hb_position_t correction_height);
205 
206 HB_EXTERN unsigned int
207 hb_ot_math_get_glyph_variants (hb_font_t *font,
208 			       hb_codepoint_t glyph,
209 			       hb_direction_t direction,
210 			       unsigned int start_offset,
211 			       unsigned int *variants_count, /* IN/OUT */
212 			       hb_ot_math_glyph_variant_t *variants /* OUT */);
213 
214 HB_EXTERN hb_position_t
215 hb_ot_math_get_min_connector_overlap (hb_font_t *font,
216 				      hb_direction_t direction);
217 
218 HB_EXTERN unsigned int
219 hb_ot_math_get_glyph_assembly (hb_font_t *font,
220 			       hb_codepoint_t glyph,
221 			       hb_direction_t direction,
222 			       unsigned int start_offset,
223 			       unsigned int *parts_count, /* IN/OUT */
224 			       hb_ot_math_glyph_part_t *parts, /* OUT */
225 			       hb_position_t *italics_correction /* OUT */);
226 
227 
228 HB_END_DECLS
229 
230 #endif /* HB_OT_MATH_H */
231