harfbuzz/src/hb-ot-math.cc

254 lines
8.3 KiB
C++

/*
* 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-open-type-private.hh"
#include "hb-ot-layout-private.hh"
#include "hb-ot-math-table.hh"
static inline const OT::MATH&
_get_math (hb_face_t *face)
{
if (unlikely (!hb_ot_shaper_face_data_ensure (face))) return OT::Null(OT::MATH);
hb_ot_layout_t * layout = hb_ot_layout_from_face (face);
return *(layout->math.get ());
}
/*
* OT::MATH
*/
/**
* hb_ot_math_has_data:
* @face: #hb_face_t to test
*
* This function allows to verify the presence of an OpenType MATH table on the
* face.
*
* Return value: true if face has a MATH table, false otherwise
*
* Since: 1.3.3
**/
hb_bool_t
hb_ot_math_has_data (hb_face_t *face)
{
return &_get_math (face) != &OT::Null(OT::MATH);
}
/**
* hb_ot_math_get_constant:
* @font: #hb_font_t from which to retrieve the value
* @constant: #hb_ot_math_constant_t the constant to retrieve
*
* This function returns the requested math constants as a #hb_position_t.
* If the request 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
* actually an integer between 0 and 100 representing that percentage.
*
* Return value: the requested constant or 0
*
* Since: 1.3.3
**/
hb_position_t
hb_ot_math_get_constant (hb_font_t *font,
hb_ot_math_constant_t constant)
{
const OT::MATH &math = _get_math (font->face);
return math.get_constant(constant, font);
}
/**
* hb_ot_math_get_glyph_italics_correction:
* @font: #hb_font_t from which to retrieve the value
* @glyph: glyph index from which to retrieve the value
*
* Return value: the italics correction of the glyph or 0
*
* Since: 1.3.3
**/
hb_position_t
hb_ot_math_get_glyph_italics_correction (hb_font_t *font,
hb_codepoint_t glyph)
{
const OT::MATH &math = _get_math (font->face);
return math.get_math_glyph_info().get_italics_correction (glyph, font);
}
/**
* hb_ot_math_get_glyph_top_accent_attachment:
* @font: #hb_font_t from which to retrieve the value
* @glyph: glyph index from which to retrieve the value
*
* Return value: the top accent attachment of the glyph or 0
*
* Since: 1.3.3
**/
hb_position_t
hb_ot_math_get_glyph_top_accent_attachment (hb_font_t *font,
hb_codepoint_t glyph)
{
const OT::MATH &math = _get_math (font->face);
return math.get_math_glyph_info().get_top_accent_attachment (glyph, font);
}
/**
* hb_ot_math_is_glyph_extended_shape:
* @face: a #hb_face_t to test
* @glyph: a glyph index to test
*
* 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)
{
const OT::MATH &math = _get_math (face);
return math.get_math_glyph_info().is_extended_shape (glyph);
}
/**
* hb_ot_math_get_glyph_kerning:
* @font: #hb_font_t from which to retrieve the value
* @glyph: 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.
*
* This function tries to retrieve the MathKern table for the specified font,
* glyph and #hb_ot_math_kern_t. Then it browses the list of heights from the
* MathKern table to find one value that is greater or equal to specified
* correction_height. If one is found the corresponding value from the list of
* kerns is returned and otherwise the last kern value is returned.
*
* Return value: requested kerning or 0
*
* 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)
{
const OT::MATH &math = _get_math (font->face);
return math.get_math_glyph_info().get_kerning (glyph, kern, correction_height, font);
}
/**
* hb_ot_math_get_glyph_variants:
* @font: #hb_font_t from which to retrieve the values
* @glyph: index of the glyph to stretch
* @direction: direction of the stretching
* @start_offset: offset of the first variant to retrieve
* @variants_count: maximum number of variants to retrieve after start_offset
* (IN) and actual number of variants retrieved (OUT)
* @variants: array of size at least @variants_count to store the result
*
* This function tries to retrieve the MathGlyphConstruction for the specified
* font, glyph and direction. Note that only the value of
* #HB_DIRECTION_IS_HORIZONTAL is considered. It provides the corresponding list
* of size variants as an array of hb_ot_math_glyph_variant_t structs.
*
* Return value: the total number of size variants available or 0
*
* 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 */)
{
const OT::MATH &math = _get_math (font->face);
return math.get_math_variants().get_glyph_variants (glyph, direction, font,
start_offset,
variants_count,
variants);
}
/**
* hb_ot_math_get_min_connector_overlap:
* @font: #hb_font_t from which to retrieve the value
* @direction: direction of the stretching
*
* This function tries to retrieve the MathVariants table for the specified
* font and returns the minimum overlap of connecting glyphs to draw a glyph
* assembly in the specified direction. Note that only the value of
* #HB_DIRECTION_IS_HORIZONTAL is considered.
*
* Return value: requested min connector overlap or 0
*
* Since: 1.3.3
**/
hb_position_t
hb_ot_math_get_min_connector_overlap (hb_font_t *font,
hb_direction_t direction)
{
const OT::MATH &math = _get_math (font->face);
return math.get_math_variants().get_min_connector_overlap (direction, font);
}
/**
* hb_ot_math_get_glyph_assembly:
* @font: #hb_font_t from which to retrieve the values
* @glyph: index of the glyph to stretch
* @direction: direction of the stretching
* @start_offset: offset of the first glyph part to retrieve
* @parts_count: maximum number of glyph parts to retrieve after start_offset
* (IN) and actual number of parts retrieved (OUT)
* @parts: array of size at least @parts_count to store the result
* @italics_correction: italic correction of the glyph assembly
*
* This function tries to retrieve the GlyphAssembly for the specified font,
* glyph and direction. Note that only the value of #HB_DIRECTION_IS_HORIZONTAL
* is considered. It provides the information necessary to draw the glyph
* assembly as an array of #hb_ot_math_glyph_part_t.
*
* 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 */)
{
const OT::MATH &math = _get_math (font->face);
return math.get_math_variants().get_glyph_parts (glyph, direction, font,
start_offset,
parts_count,
parts,
italics_correction);
}