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Diffstat (limited to 'gfx/harfbuzz/src/hb-ot-math.cc')
| -rw-r--r-- | gfx/harfbuzz/src/hb-ot-math.cc | 338 |
1 files changed, 338 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-ot-math.cc b/gfx/harfbuzz/src/hb-ot-math.cc new file mode 100644 index 0000000000..c515867bdf --- /dev/null +++ b/gfx/harfbuzz/src/hb-ot-math.cc @@ -0,0 +1,338 @@ +/* + * Copyright © 2016 Igalia S.L. + * + * This is part of HarfBuzz, a text shaping library. + * + * Permission is hereby granted, without written agreement and without + * license or royalty fees, to use, copy, modify, and distribute this + * software and its documentation for any purpose, provided that the + * above copyright notice and the following two paragraphs appear in + * all copies of this software. + * + * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR + * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES + * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN + * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH + * DAMAGE. + * + * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, + * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND + * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS + * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO + * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. + * + * Igalia Author(s): Frédéric Wang + */ + +#include "hb.hh" + +#ifndef HB_NO_MATH + +#include "hb-ot-math-table.hh" + + +/** + * SECTION:hb-ot-math + * @title: hb-ot-math + * @short_description: OpenType Math information + * @include: hb-ot.h + * + * Functions for fetching mathematics layout data from OpenType fonts. + * + * HarfBuzz itself does not implement a math layout solution. The + * functions and types provided can be used by client programs to access + * the font data necessary for typesetting OpenType Math layout. + * + **/ + + +/* + * OT::MATH + */ + +/** + * hb_ot_math_has_data: + * @face: #hb_face_t to test + * + * Tests whether a face has a `MATH` table. + * + * Return value: `true` if the table is found, `false` otherwise + * + * Since: 1.3.3 + **/ +hb_bool_t +hb_ot_math_has_data (hb_face_t *face) +{ + return face->table.MATH->has_data (); +} + +/** + * hb_ot_math_get_constant: + * @font: #hb_font_t to work upon + * @constant: #hb_ot_math_constant_t the constant to retrieve + * + * Fetches the specified math constant. For most constants, the value returned + * is an #hb_position_t. + * + * However, if the requested constant is #HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN, + * #HB_OT_MATH_CONSTANT_SCRIPT_SCRIPT_PERCENT_SCALE_DOWN or + * #HB_OT_MATH_CONSTANT_SCRIPT_PERCENT_SCALE_DOWN, then the return value is + * an integer between 0 and 100 representing that percentage. + * + * Return value: the requested constant or zero + * + * Since: 1.3.3 + **/ +hb_position_t +hb_ot_math_get_constant (hb_font_t *font, + hb_ot_math_constant_t constant) +{ + return font->face->table.MATH->get_constant(constant, font); +} + +/** + * hb_ot_math_get_glyph_italics_correction: + * @font: #hb_font_t to work upon + * @glyph: The glyph index from which to retrieve the value + * + * Fetches an italics-correction value (if one exists) for the specified + * glyph index. + * + * Return value: the italics correction of the glyph or zero + * + * Since: 1.3.3 + **/ +hb_position_t +hb_ot_math_get_glyph_italics_correction (hb_font_t *font, + hb_codepoint_t glyph) +{ + return font->face->table.MATH->get_glyph_info().get_italics_correction (glyph, font); +} + +/** + * hb_ot_math_get_glyph_top_accent_attachment: + * @font: #hb_font_t to work upon + * @glyph: The glyph index from which to retrieve the value + * + * Fetches a top-accent-attachment value (if one exists) for the specified + * glyph index. + * + * For any glyph that does not have a top-accent-attachment value - that is, + * a glyph not covered by the `MathTopAccentAttachment` table (or, when + * @font has no `MathTopAccentAttachment` table or no `MATH` table, any + * glyph) - the function synthesizes a value, returning the position at + * one-half the glyph's advance width. + * + * Return value: the top accent attachment of the glyph or 0.5 * the advance + * width of @glyph + * + * Since: 1.3.3 + **/ +hb_position_t +hb_ot_math_get_glyph_top_accent_attachment (hb_font_t *font, + hb_codepoint_t glyph) +{ + return font->face->table.MATH->get_glyph_info().get_top_accent_attachment (glyph, font); +} + +/** + * hb_ot_math_is_glyph_extended_shape: + * @face: #hb_face_t to work upon + * @glyph: The glyph index to test + * + * Tests whether the given glyph index is an extended shape in the face. + * + * Return value: `true` if the glyph is an extended shape, `false` otherwise + * + * Since: 1.3.3 + **/ +hb_bool_t +hb_ot_math_is_glyph_extended_shape (hb_face_t *face, + hb_codepoint_t glyph) +{ + return face->table.MATH->get_glyph_info().is_extended_shape (glyph); +} + +/** + * hb_ot_math_get_glyph_kerning: + * @font: #hb_font_t to work upon + * @glyph: The glyph index from which to retrieve the value + * @kern: The #hb_ot_math_kern_t from which to retrieve the value + * @correction_height: the correction height to use to determine the kerning. + * + * Fetches the math kerning (cut-ins) value for the specified font, glyph index, and + * @kern. + * + * If the MathKern table is found, the function examines it to find a height + * value that is greater or equal to @correction_height. If such a height + * value is found, corresponding kerning value from the table is returned. If + * no such height value is found, the last kerning value is returned. + * + * Return value: requested kerning value or zero + * + * Since: 1.3.3 + **/ +hb_position_t +hb_ot_math_get_glyph_kerning (hb_font_t *font, + hb_codepoint_t glyph, + hb_ot_math_kern_t kern, + hb_position_t correction_height) +{ + return font->face->table.MATH->get_glyph_info().get_kerning (glyph, + kern, + correction_height, + font); +} + +/** + * hb_ot_math_get_glyph_kernings: + * @font: #hb_font_t to work upon + * @glyph: The glyph index from which to retrieve the kernings + * @kern: The #hb_ot_math_kern_t from which to retrieve the kernings + * @start_offset: offset of the first kern entry to retrieve + * @entries_count: (inout) (optional): Input = the maximum number of kern entries to return; + * Output = the actual number of kern entries returned + * @kern_entries: (out caller-allocates) (array length=entries_count): array of kern entries returned + * + * Fetches the raw MathKern (cut-in) data for the specified font, glyph index, + * and @kern. The corresponding list of kern values and correction heights is + * returned as a list of #hb_ot_math_kern_entry_t structs. + * + * See also #hb_ot_math_get_glyph_kerning, which handles selecting the + * appropriate kern value for a given correction height. + * + * <note>For a glyph with @n defined kern values (where @n > 0), there are only + * @n−1 defined correction heights, as each correction height defines a boundary + * past which the next kern value should be selected. Therefore, only the + * #hb_ot_math_kern_entry_t.kern_value of the uppermost #hb_ot_math_kern_entry_t + * actually comes from the font; its corresponding + * #hb_ot_math_kern_entry_t.max_correction_height is always set to + * <code>INT32_MAX</code>.</note> + * + * Return value: the total number of kern values available or zero + * + * Since: 3.4.0 + **/ +unsigned int +hb_ot_math_get_glyph_kernings (hb_font_t *font, + hb_codepoint_t glyph, + hb_ot_math_kern_t kern, + unsigned int start_offset, + unsigned int *entries_count, /* IN/OUT */ + hb_ot_math_kern_entry_t *kern_entries /* OUT */) +{ + return font->face->table.MATH->get_glyph_info().get_kernings (glyph, + kern, + start_offset, + entries_count, + kern_entries, + font); +} + +/** + * hb_ot_math_get_glyph_variants: + * @font: #hb_font_t to work upon + * @glyph: The index of the glyph to stretch + * @direction: The direction of the stretching (horizontal or vertical) + * @start_offset: offset of the first variant to retrieve + * @variants_count: (inout): Input = the maximum number of variants to return; + * Output = the actual number of variants returned + * @variants: (out) (array length=variants_count): array of variants returned + * + * Fetches the MathGlyphConstruction for the specified font, glyph index, and + * direction. The corresponding list of size variants is returned as a list of + * #hb_ot_math_glyph_variant_t structs. + * + * <note>The @direction parameter is only used to select between horizontal + * or vertical directions for the construction. Even though all #hb_direction_t + * values are accepted, only the result of #HB_DIRECTION_IS_HORIZONTAL is + * considered.</note> + * + * Return value: the total number of size variants available or zero + * + * Since: 1.3.3 + **/ +unsigned int +hb_ot_math_get_glyph_variants (hb_font_t *font, + hb_codepoint_t glyph, + hb_direction_t direction, + unsigned int start_offset, + unsigned int *variants_count, /* IN/OUT */ + hb_ot_math_glyph_variant_t *variants /* OUT */) +{ + return font->face->table.MATH->get_variants().get_glyph_variants (glyph, direction, font, + start_offset, + variants_count, + variants); +} + +/** + * hb_ot_math_get_min_connector_overlap: + * @font: #hb_font_t to work upon + * @direction: direction of the stretching (horizontal or vertical) + * + * Fetches the MathVariants table for the specified font and returns the + * minimum overlap of connecting glyphs that are required to draw a glyph + * assembly in the specified direction. + * + * <note>The @direction parameter is only used to select between horizontal + * or vertical directions for the construction. Even though all #hb_direction_t + * values are accepted, only the result of #HB_DIRECTION_IS_HORIZONTAL is + * considered.</note> + * + * Return value: requested minimum connector overlap or zero + * + * Since: 1.3.3 + **/ +hb_position_t +hb_ot_math_get_min_connector_overlap (hb_font_t *font, + hb_direction_t direction) +{ + return font->face->table.MATH->get_variants().get_min_connector_overlap (direction, font); +} + +/** + * hb_ot_math_get_glyph_assembly: + * @font: #hb_font_t to work upon + * @glyph: The index of the glyph to stretch + * @direction: direction of the stretching (horizontal or vertical) + * @start_offset: offset of the first glyph part to retrieve + * @parts_count: (inout): Input = maximum number of glyph parts to return; + * Output = actual number of parts returned + * @parts: (out) (array length=parts_count): the glyph parts returned + * @italics_correction: (out): italics correction of the glyph assembly + * + * Fetches the GlyphAssembly for the specified font, glyph index, and direction. + * Returned are a list of #hb_ot_math_glyph_part_t glyph parts that can be + * used to draw the glyph and an italics-correction value (if one is defined + * in the font). + * + * <note>The @direction parameter is only used to select between horizontal + * or vertical directions for the construction. Even though all #hb_direction_t + * values are accepted, only the result of #HB_DIRECTION_IS_HORIZONTAL is + * considered.</note> + * + * Return value: the total number of parts in the glyph assembly + * + * Since: 1.3.3 + **/ +unsigned int +hb_ot_math_get_glyph_assembly (hb_font_t *font, + hb_codepoint_t glyph, + hb_direction_t direction, + unsigned int start_offset, + unsigned int *parts_count, /* IN/OUT */ + hb_ot_math_glyph_part_t *parts, /* OUT */ + hb_position_t *italics_correction /* OUT */) +{ + return font->face->table.MATH->get_variants().get_glyph_parts (glyph, + direction, + font, + start_offset, + parts_count, + parts, + italics_correction); +} + + +#endif |