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.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_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
	/*
	* 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_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