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 #include "hb-open-type.hh"
28
29 #include "hb-ot-face.hh"
30 #include "hb-ot-math-table.hh"
31
32
33 /**
34 * SECTION:hb-ot-math
35 * @title: hb-ot-math
36 * @short_description: OpenType Math information
37 * @include: hb-ot.h
38 *
39 * Functions for fetching mathematics layout data from OpenType fonts.
40 **/
41
42
43 /*
44 * OT::MATH
45 */
46
47 /**
48 * hb_ot_math_has_data:
49 * @face: #hb_face_t to test
50 *
51 * This function allows to verify the presence of an OpenType MATH table on the
52 * face.
53 *
54 * Return value: true if face has a MATH table, false otherwise
55 *
56 * Since: 1.3.3
57 **/
58 hb_bool_t
59 hb_ot_math_has_data (hb_face_t *face)
60 {
61 return face->table.MATH->has_data ();
62 }
63
64 /**
65 * hb_ot_math_get_constant:
66 * @font: #hb_font_t from which to retrieve the value
67 * @constant: #hb_ot_math_constant_t the constant to retrieve
68 *
69 * This function returns the requested math constants as a #hb_position_t.
70 * If the request constant is HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN,
71 * HB_OT_MATH_CONSTANT_SCRIPT_SCRIPT_PERCENT_SCALE_DOWN or
72 * HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN then the return value is
73 * actually an integer between 0 and 100 representing that percentage.
74 *
75 * Return value: the requested constant or 0
76 *
77 * Since: 1.3.3
78 **/
79 hb_position_t
80 hb_ot_math_get_constant (hb_font_t *font,
81 hb_ot_math_constant_t constant)
82 {
83 return font->face->table.MATH->get_constant(constant, font);
84 }
85
86 /**
87 * hb_ot_math_get_glyph_italics_correction:
88 * @font: #hb_font_t from which to retrieve the value
89 * @glyph: glyph index from which to retrieve the value
90 *
91 * Return value: the italics correction of the glyph or 0
92 *
93 * Since: 1.3.3
94 **/
95 hb_position_t
96 hb_ot_math_get_glyph_italics_correction (hb_font_t *font,
97 hb_codepoint_t glyph)
98 {
99 return font->face->table.MATH->get_glyph_info().get_italics_correction (glyph, font);
100 }
101
102 /**
103 * hb_ot_math_get_glyph_top_accent_attachment:
104 * @font: #hb_font_t from which to retrieve the value
105 * @glyph: glyph index from which to retrieve the value
106 *
107 * Return value: the top accent attachment of the glyph or 0
108 *
109 * Since: 1.3.3
110 **/
111 hb_position_t
112 hb_ot_math_get_glyph_top_accent_attachment (hb_font_t *font,
113 hb_codepoint_t glyph)
114 {
115 return font->face->table.MATH->get_glyph_info().get_top_accent_attachment (glyph, font);
116 }
117
118 /**
119 * hb_ot_math_is_glyph_extended_shape:
120 * @face: a #hb_face_t to test
121 * @glyph: a glyph index to test
122 *
123 * Return value: true if the glyph is an extended shape, false otherwise
124 *
125 * Since: 1.3.3
126 **/
127 hb_bool_t
128 hb_ot_math_is_glyph_extended_shape (hb_face_t *face,
129 hb_codepoint_t glyph)
130 {
131 return face->table.MATH->get_glyph_info().is_extended_shape (glyph);
132 }
133
134 /**
135 * hb_ot_math_get_glyph_kerning:
136 * @font: #hb_font_t from which to retrieve the value
137 * @glyph: glyph index from which to retrieve the value
138 * @kern: the #hb_ot_math_kern_t from which to retrieve the value
139 * @correction_height: the correction height to use to determine the kerning.
140 *
141 * This function tries to retrieve the MathKern table for the specified font,
142 * glyph and #hb_ot_math_kern_t. Then it browses the list of heights from the
143 * MathKern table to find one value that is greater or equal to specified
144 * correction_height. If one is found the corresponding value from the list of
145 * kerns is returned and otherwise the last kern value is returned.
146 *
147 * Return value: requested kerning or 0
148 *
149 * Since: 1.3.3
150 **/
151 hb_position_t
152 hb_ot_math_get_glyph_kerning (hb_font_t *font,
153 hb_codepoint_t glyph,
154 hb_ot_math_kern_t kern,
155 hb_position_t correction_height)
156 {
157 return font->face->table.MATH->get_glyph_info().get_kerning (glyph,
158 kern,
159 correction_height,
160 font);
161 }
162
163 /**
164 * hb_ot_math_get_glyph_variants:
165 * @font: #hb_font_t from which to retrieve the values
166 * @glyph: index of the glyph to stretch
167 * @direction: direction of the stretching
168 * @start_offset: offset of the first variant to retrieve
169 * @variants_count: maximum number of variants to retrieve after start_offset
170 * (IN) and actual number of variants retrieved (OUT)
171 * @variants: array of size at least @variants_count to store the result
172 *
173 * This function tries to retrieve the MathGlyphConstruction for the specified
174 * font, glyph and direction. Note that only the value of
175 * #HB_DIRECTION_IS_HORIZONTAL is considered. It provides the corresponding list
176 * of size variants as an array of hb_ot_math_glyph_variant_t structs.
177 *
178 * Return value: the total number of size variants available or 0
179 *
180 * Since: 1.3.3
181 **/
182 unsigned int
183 hb_ot_math_get_glyph_variants (hb_font_t *font,
184 hb_codepoint_t glyph,
185 hb_direction_t direction,
186 unsigned int start_offset,
187 unsigned int *variants_count, /* IN/OUT */
188 hb_ot_math_glyph_variant_t *variants /* OUT */)
189 {
190 return font->face->table.MATH->get_variants().get_glyph_variants (glyph, direction, font,
191 start_offset,
192 variants_count,
193 variants);
194 }
195
196 /**
197 * hb_ot_math_get_min_connector_overlap:
198 * @font: #hb_font_t from which to retrieve the value
199 * @direction: direction of the stretching
200 *
201 * This function tries to retrieve the MathVariants table for the specified
202 * font and returns the minimum overlap of connecting glyphs to draw a glyph
203 * assembly in the specified direction. Note that only the value of
204 * #HB_DIRECTION_IS_HORIZONTAL is considered.
205 *
206 * Return value: requested min connector overlap or 0
207 *
208 * Since: 1.3.3
209 **/
210 hb_position_t
211 hb_ot_math_get_min_connector_overlap (hb_font_t *font,
212 hb_direction_t direction)
213 {
214 return font->face->table.MATH->get_variants().get_min_connector_overlap (direction, font);
215 }
216
217 /**
218 * hb_ot_math_get_glyph_assembly:
219 * @font: #hb_font_t from which to retrieve the values
220 * @glyph: index of the glyph to stretch
221 * @direction: direction of the stretching
222 * @start_offset: offset of the first glyph part to retrieve
223 * @parts_count: maximum number of glyph parts to retrieve after start_offset
224 * (IN) and actual number of parts retrieved (OUT)
225 * @parts: array of size at least @parts_count to store the result
226 * @italics_correction: italic correction of the glyph assembly
227 *
228 * This function tries to retrieve the GlyphAssembly for the specified font,
229 * glyph and direction. Note that only the value of #HB_DIRECTION_IS_HORIZONTAL
230 * is considered. It provides the information necessary to draw the glyph
231 * assembly as an array of #hb_ot_math_glyph_part_t.
232 *
233 * Return value: the total number of parts in the glyph assembly
234 *
235 * Since: 1.3.3
236 **/
237 unsigned int
238 hb_ot_math_get_glyph_assembly (hb_font_t *font,
239 hb_codepoint_t glyph,
240 hb_direction_t direction,
241 unsigned int start_offset,
242 unsigned int *parts_count, /* IN/OUT */
243 hb_ot_math_glyph_part_t *parts, /* OUT */
244 hb_position_t *italics_correction /* OUT */)
245 {
246 return font->face->table.MATH->get_variants().get_glyph_parts (glyph,
247 direction,
248 font,
249 start_offset,
250 parts_count,
251 parts,
252 italics_correction);
253 }