Roll HarfBuzz to 1.4.1

third_party/harfbuzz-ng/src/hb-ot-math.cc

+/*
+ * 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-math-table.hh"
+
+HB_SHAPER_DATA_ENSURE_DECLARE(ot, face)
+
+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);
+
+retry:
+  const OT::MATH *math = (const OT::MATH *) hb_atomic_ptr_get (&layout->math);
+
+  if (unlikely (!math))
+  {
+    hb_blob_t *blob = OT::Sanitizer<OT::MATH>::sanitize (face->reference_table (HB_OT_TAG_MATH));
+    math = OT::Sanitizer<OT::MATH>::lock_instance (blob);
+    if (!hb_atomic_ptr_cmpexch (&layout->math, NULL, math))
+    {
+      hb_blob_destroy (blob);
+      goto retry;
+    }
+    layout->math_blob = blob;
+  }
+
+  return *math;
+}
+
+/*
+ * 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. If so, such a table will be loaded into memory and sanitized. You can
+ * then safely call other functions for math layout and shaping.
+ *
+ * Return value: #TRUE if face has a MATH table and #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:
+ * @font: a #hb_font_t to test
+ * @glyph: a glyph index to test
+ *
+ * Return value: #TRUE if the glyph is an extended shape and #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);
+}