src/hb-ot-math.cc - third_party/harfbuzz - Git at Google

 /*
  * 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);
 }
	/*
	* 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);
	}