chromium/third_party/harfbuzz-ng/src/src/hb-ot-metrics.cc

/*
 * Copyright © 2018-2019  Ebrahim Byagowi
 *
 *  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.
 */

#include "hb.hh"

#include "hb-ot-var-mvar-table.hh"
#include "hb-ot-gasp-table.hh" // Just so we compile it; unused otherwise.
#include "hb-ot-os2-table.hh"
#include "hb-ot-post-table.hh"
#include "hb-ot-hhea-table.hh"
#include "hb-ot-metrics.hh"
#include "hb-ot-face.hh"


/**
 * SECTION:hb-ot-metrics
 * @title: hb-ot-metrics
 * @short_description: OpenType Metrics
 * @include: hb-ot.h
 *
 * Functions for fetching metrics from fonts.
 **/

static float
_fix_ascender_descender (float value, hb_ot_metrics_tag_t metrics_tag)
{ … }

/* The common part of _get_position logic needed on hb-ot-font and here
   to be able to have slim builds without the not always needed parts */
bool
_hb_ot_metrics_get_position_common (hb_font_t           *font,
				    hb_ot_metrics_tag_t  metrics_tag,
				    hb_position_t       *position     /* OUT.  May be NULL. */)
{ … }

#ifndef HB_NO_METRICS

#if 0
static bool
_get_gasp (hb_face_t *face, float *result, hb_ot_metrics_tag_t metrics_tag)
{
  const OT::GaspRange& range = face->table.gasp->get_gasp_range (metrics_tag - HB_TAG ('g','s','p','0'));
  if (&range == &Null (OT::GaspRange)) return false;
  if (result) *result = range.rangeMaxPPEM + font->face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords);
  return true;
}
#endif

/* Private tags for https://github.com/harfbuzz/harfbuzz/issues/1866 */
#define _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_OS2 …
#define _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_HHEA …
#define _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_OS2 …
#define _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_HHEA …
#define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_OS2 …
#define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_HHEA …

/**
 * hb_ot_metrics_get_position:
 * @font: an #hb_font_t object.
 * @metrics_tag: tag of metrics value you like to fetch.
 * @position: (out) (optional): result of metrics value from the font.
 *
 * Fetches metrics value corresponding to @metrics_tag from @font.
 *
 * Returns: Whether found the requested metrics in the font.
 * Since: 2.6.0
 **/
hb_bool_t
hb_ot_metrics_get_position (hb_font_t           *font,
			    hb_ot_metrics_tag_t  metrics_tag,
			    hb_position_t       *position     /* OUT.  May be NULL. */)
{ … }

/**
 * hb_ot_metrics_get_position_with_fallback:
 * @font: an #hb_font_t object.
 * @metrics_tag: tag of metrics value you like to fetch.
 * @position: (out) (optional): result of metrics value from the font.
 *
 * Fetches metrics value corresponding to @metrics_tag from @font,
 * and synthesizes a value if it the value is missing in the font.
 *
 * Since: 4.0.0
 **/
void
hb_ot_metrics_get_position_with_fallback (hb_font_t           *font,
					  hb_ot_metrics_tag_t  metrics_tag,
					  hb_position_t       *position     /* OUT */)
{ … }

#ifndef HB_NO_VAR
/**
 * hb_ot_metrics_get_variation:
 * @font: an #hb_font_t object.
 * @metrics_tag: tag of metrics value you like to fetch.
 *
 * Fetches metrics value corresponding to @metrics_tag from @font with the
 * current font variation settings applied.
 *
 * Returns: The requested metric value.
 *
 * Since: 2.6.0
 **/
float
hb_ot_metrics_get_variation (hb_font_t *font, hb_ot_metrics_tag_t metrics_tag)
{ … }

/**
 * hb_ot_metrics_get_x_variation:
 * @font: an #hb_font_t object.
 * @metrics_tag: tag of metrics value you like to fetch.
 *
 * Fetches horizontal metrics value corresponding to @metrics_tag from @font
 * with the current font variation settings applied.
 *
 * Returns: The requested metric value.
 *
 * Since: 2.6.0
 **/
hb_position_t
hb_ot_metrics_get_x_variation (hb_font_t *font, hb_ot_metrics_tag_t metrics_tag)
{ … }

/**
 * hb_ot_metrics_get_y_variation:
 * @font: an #hb_font_t object.
 * @metrics_tag: tag of metrics value you like to fetch.
 *
 * Fetches vertical metrics value corresponding to @metrics_tag from @font with
 * the current font variation settings applied.
 *
 * Returns: The requested metric value.
 *
 * Since: 2.6.0
 **/
hb_position_t
hb_ot_metrics_get_y_variation (hb_font_t *font, hb_ot_metrics_tag_t metrics_tag)
{ … }
#endif

#endif