HarfBuzz text shaping engine
http://harfbuzz.github.io/
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293 lines
9.4 KiB
293 lines
9.4 KiB
/* |
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* Copyright © 2016 Igalia S.L. |
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* |
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* This is part of HarfBuzz, a text shaping library. |
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* |
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* Permission is hereby granted, without written agreement and without |
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* license or royalty fees, to use, copy, modify, and distribute this |
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* software and its documentation for any purpose, provided that the |
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* above copyright notice and the following two paragraphs appear in |
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* all copies of this software. |
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* |
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR |
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES |
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN |
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH |
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* DAMAGE. |
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* |
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, |
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND |
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS |
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO |
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. |
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* |
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* Igalia Author(s): Frédéric Wang |
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*/ |
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#include "hb.hh" |
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#ifndef HB_NO_MATH |
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#include "hb-ot-math-table.hh" |
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/** |
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* SECTION:hb-ot-math |
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* @title: hb-ot-math |
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* @short_description: OpenType Math information |
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* @include: hb-ot.h |
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* |
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* Functions for fetching mathematics layout data from OpenType fonts. |
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* |
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* HarfBuzz itself does not implement a math layout solution. The |
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* functions and types provided can be used by client programs to access |
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* the font data necessary for typesetting OpenType Math layout. |
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* |
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**/ |
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/* |
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* OT::MATH |
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*/ |
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/** |
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* hb_ot_math_has_data: |
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* @face: #hb_face_t to test |
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* |
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* Tests whether a face has a `MATH` table. |
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* |
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* Return value: %true if the table is found, %false otherwise |
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* |
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* Since: 1.3.3 |
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**/ |
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hb_bool_t |
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hb_ot_math_has_data (hb_face_t *face) |
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{ |
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return face->table.MATH->has_data (); |
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} |
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/** |
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* hb_ot_math_get_constant: |
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* @font: #hb_font_t to work upon |
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* @constant: #hb_ot_math_constant_t the constant to retrieve |
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* |
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* Fetches the specified math constant. For most constants, the value returned |
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* is an #hb_position_t. |
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* |
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* However, if the requested constant is #HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN, |
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* #HB_OT_MATH_CONSTANT_SCRIPT_SCRIPT_PERCENT_SCALE_DOWN or |
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* #HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN, then the return value is |
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* an integer between 0 and 100 representing that percentage. |
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* |
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* Return value: the requested constant or zero |
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* |
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* Since: 1.3.3 |
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**/ |
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hb_position_t |
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hb_ot_math_get_constant (hb_font_t *font, |
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hb_ot_math_constant_t constant) |
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{ |
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return font->face->table.MATH->get_constant(constant, font); |
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} |
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/** |
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* hb_ot_math_get_glyph_italics_correction: |
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* @font: #hb_font_t to work upon |
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* @glyph: The glyph index from which to retrieve the value |
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* |
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* Fetches an italics-correction value (if one exists) for the specified |
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* glyph index. |
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* |
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* Return value: the italics correction of the glyph or zero |
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* |
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* Since: 1.3.3 |
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**/ |
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hb_position_t |
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hb_ot_math_get_glyph_italics_correction (hb_font_t *font, |
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hb_codepoint_t glyph) |
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{ |
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return font->face->table.MATH->get_glyph_info().get_italics_correction (glyph, font); |
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} |
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/** |
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* hb_ot_math_get_glyph_top_accent_attachment: |
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* @font: #hb_font_t to work upon |
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* @glyph: The glyph index from which to retrieve the value |
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* |
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* Fetches a top-accent-attachment value (if one exists) for the specified |
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* glyph index. |
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* |
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* For any glyph that does not have a top-accent-attachment value - that is, |
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* a glyph not covered by the `MathTopAccentAttachment` table (or, when |
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* @font has no `MathTopAccentAttachment` table or no `MATH` table, any |
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* glyph) - the function synthesizes a value, returning the position at |
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* one-half the glyph's advance width. |
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* |
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* Return value: the top accent attachment of the glyph or 0.5 * the advance |
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* width of @glyph |
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* |
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* Since: 1.3.3 |
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**/ |
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hb_position_t |
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hb_ot_math_get_glyph_top_accent_attachment (hb_font_t *font, |
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hb_codepoint_t glyph) |
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{ |
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return font->face->table.MATH->get_glyph_info().get_top_accent_attachment (glyph, font); |
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} |
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/** |
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* hb_ot_math_is_glyph_extended_shape: |
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* @face: #hb_face_t to work upon |
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* @glyph: The glyph index to test |
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* |
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* Tests whether the given glyph index is an extended shape in the face. |
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* |
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* Return value: %true if the glyph is an extended shape, %false otherwise |
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* |
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* Since: 1.3.3 |
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**/ |
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hb_bool_t |
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hb_ot_math_is_glyph_extended_shape (hb_face_t *face, |
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hb_codepoint_t glyph) |
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{ |
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return face->table.MATH->get_glyph_info().is_extended_shape (glyph); |
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} |
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/** |
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* hb_ot_math_get_glyph_kerning: |
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* @font: #hb_font_t to work upon |
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* @glyph: The glyph index from which to retrieve the value |
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* @kern: The #hb_ot_math_kern_t from which to retrieve the value |
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* @correction_height: the correction height to use to determine the kerning. |
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* |
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* Fetches the math kerning (cut-ins) value for the specified font, glyph index, and |
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* @kern. |
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* |
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* If the MathKern table is found, the function examines it to find a height |
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* value that is greater or equal to @correction_height. If such a height |
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* value is found, corresponding kerning value from the table is returned. If |
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* no such height value is found, the last kerning value is returned. |
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* |
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* Return value: requested kerning value or zero |
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* |
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* Since: 1.3.3 |
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**/ |
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hb_position_t |
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hb_ot_math_get_glyph_kerning (hb_font_t *font, |
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hb_codepoint_t glyph, |
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hb_ot_math_kern_t kern, |
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hb_position_t correction_height) |
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{ |
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return font->face->table.MATH->get_glyph_info().get_kerning (glyph, |
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kern, |
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correction_height, |
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font); |
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} |
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/** |
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* hb_ot_math_get_glyph_variants: |
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* @font: #hb_font_t to work upon |
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* @glyph: The index of the glyph to stretch |
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* @direction: The direction of the stretching (horizontal or vertical) |
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* @start_offset: offset of the first variant to retrieve |
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* @variants_count: (inout): Input = the maximum number of variants to return; |
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* Output = the actual number of variants returned |
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* @variants: (out) (array length=variants_count): array of variants returned |
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* |
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* Fetches the MathGlyphConstruction for the specified font, glyph index, and |
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* direction. The corresponding list of size variants is returned as a list of |
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* #hb_ot_math_glyph_variant_t structs. |
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* |
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* <note>The @direction parameter is only used to select between horizontal |
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* or vertical directions for the construction. Even though all #hb_direction_t |
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* values are accepted, only the result of #HB_DIRECTION_IS_HORIZONTAL is |
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* considered.</note> |
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* |
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* Return value: the total number of size variants available or zero |
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* |
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* Since: 1.3.3 |
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**/ |
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unsigned int |
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hb_ot_math_get_glyph_variants (hb_font_t *font, |
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hb_codepoint_t glyph, |
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hb_direction_t direction, |
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unsigned int start_offset, |
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unsigned int *variants_count, /* IN/OUT */ |
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hb_ot_math_glyph_variant_t *variants /* OUT */) |
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{ |
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return font->face->table.MATH->get_variants().get_glyph_variants (glyph, direction, font, |
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start_offset, |
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variants_count, |
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variants); |
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} |
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/** |
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* hb_ot_math_get_min_connector_overlap: |
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* @font: #hb_font_t to work upon |
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* @direction: direction of the stretching (horizontal or vertical) |
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* |
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* Fetches the MathVariants table for the specified font and returns the |
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* minimum overlap of connecting glyphs that are required to draw a glyph |
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* assembly in the specified direction. |
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* |
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* <note>The @direction parameter is only used to select between horizontal |
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* or vertical directions for the construction. Even though all #hb_direction_t |
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* values are accepted, only the result of #HB_DIRECTION_IS_HORIZONTAL is |
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* considered.</note> |
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* |
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* Return value: requested minimum connector overlap or zero |
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* |
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* Since: 1.3.3 |
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**/ |
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hb_position_t |
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hb_ot_math_get_min_connector_overlap (hb_font_t *font, |
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hb_direction_t direction) |
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{ |
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return font->face->table.MATH->get_variants().get_min_connector_overlap (direction, font); |
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} |
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/** |
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* hb_ot_math_get_glyph_assembly: |
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* @font: #hb_font_t to work upon |
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* @glyph: The index of the glyph to stretch |
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* @direction: direction of the stretching (horizontal or vertical) |
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* @start_offset: offset of the first glyph part to retrieve |
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* @parts_count: (inout): Input = maximum number of glyph parts to return; |
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* Output = actual number of parts returned |
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* @parts: (out) (array length=parts_count): the glyph parts returned |
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* @italics_correction: (out): italics correction of the glyph assembly |
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* |
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* Fetches the GlyphAssembly for the specified font, glyph index, and direction. |
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* Returned are a list of #hb_ot_math_glyph_part_t glyph parts that can be |
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* used to draw the glyph and an italics-correction value (if one is defined |
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* in the font). |
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* |
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* <note>The @direction parameter is only used to select between horizontal |
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* or vertical directions for the construction. Even though all #hb_direction_t |
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* values are accepted, only the result of #HB_DIRECTION_IS_HORIZONTAL is |
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* considered.</note> |
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* |
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* Return value: the total number of parts in the glyph assembly |
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* |
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* Since: 1.3.3 |
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**/ |
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unsigned int |
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hb_ot_math_get_glyph_assembly (hb_font_t *font, |
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hb_codepoint_t glyph, |
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hb_direction_t direction, |
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unsigned int start_offset, |
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unsigned int *parts_count, /* IN/OUT */ |
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hb_ot_math_glyph_part_t *parts, /* OUT */ |
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hb_position_t *italics_correction /* OUT */) |
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{ |
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return font->face->table.MATH->get_variants().get_glyph_parts (glyph, |
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direction, |
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font, |
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start_offset, |
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parts_count, |
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parts, |
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italics_correction); |
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} |
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#endif
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