/work/workdir/UnpackedTarball/harfbuzz/src/hb-ot-metrics.cc

Source
/*
 * 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)
{
  if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER ||
      metrics_tag == HB_OT_METRICS_TAG_VERTICAL_ASCENDER)
    return fabs ((double) value);
  if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER ||
      metrics_tag == HB_OT_METRICS_TAG_VERTICAL_DESCENDER)
    return -fabs ((double) value);
  return value;
}

/* 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. */)
{
  hb_face_t *face = font->face;
  switch ((unsigned) metrics_tag)
  {
#ifndef HB_NO_VAR
#define GET_VAR face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords)
#else
#define GET_VAR .0f
#endif
#define GET_METRIC_Y(TABLE, ATTR) \
  (face->table.TABLE->has_data () && \
    ((void) (position && (*position = font->em_scalef_y (_fix_ascender_descender ( \
      face->table.TABLE->ATTR + GET_VAR, metrics_tag)))), true))
#define GET_HEA_METRIC_X(TABLE, ATTR) \
  (face->table.TABLE->has_data () && \
    ((void) (position && (*position = font->em_scalef_x (_fix_ascender_descender ( \
      HB_DUAL_GET (*face->table.TABLE, table->ATTR) + GET_VAR, metrics_tag)))), true))
#define GET_HEA_METRIC_Y(TABLE, ATTR) \
  (face->table.TABLE->has_data () && \
    ((void) (position && (*position = font->em_scalef_y (_fix_ascender_descender ( \
      HB_DUAL_GET (*face->table.TABLE, table->ATTR) + GET_VAR, metrics_tag)))), true))

  case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
    return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoAscender)) ||
     GET_HEA_METRIC_Y (hhea, ascender);
  case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
    return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoDescender)) ||
     GET_HEA_METRIC_Y (hhea, descender);
  case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
    return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoLineGap)) ||
     GET_HEA_METRIC_Y (hhea, lineGap);

#ifndef HB_NO_VERTICAL
  case HB_OT_METRICS_TAG_VERTICAL_ASCENDER:  return GET_HEA_METRIC_X (vhea, ascender);
  case HB_OT_METRICS_TAG_VERTICAL_DESCENDER: return GET_HEA_METRIC_X (vhea, descender);
  case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP:  return GET_HEA_METRIC_X (vhea, lineGap);
#endif

#undef GET_HEA_METRIC_Y
#undef GET_HEA_METRIC_X
#undef GET_METRIC_Y
#undef GET_VAR
  default:                               assert (0); return false;
  }
}

#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   HB_TAG ('O','a','s','c')
#define _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_HHEA  HB_TAG ('H','a','s','c')
#define _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_OS2  HB_TAG ('O','d','s','c')
#define _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_HHEA HB_TAG ('H','d','s','c')
#define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_OS2   HB_TAG ('O','l','g','p')
#define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_HHEA  HB_TAG ('H','l','g','p')

/**
 * 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_face_t *face = font->face;
  switch ((unsigned) metrics_tag)
  {
  case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
  case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
  case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
  case HB_OT_METRICS_TAG_VERTICAL_ASCENDER:
  case HB_OT_METRICS_TAG_VERTICAL_DESCENDER:
  case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP:           return _hb_ot_metrics_get_position_common (font, metrics_tag, position);
#ifndef HB_NO_VAR
#define GET_VAR hb_ot_metrics_get_variation (font, metrics_tag)
#else
#define GET_VAR 0
#endif
#define GET_METRIC_X(TABLE, ATTR) \
  (face->table.TABLE->has_data () && \
    ((void) (position && (*position = font->em_scalef_x (face->table.TABLE->ATTR + GET_VAR))), true))
#define GET_METRIC_Y(TABLE, ATTR) \
  (face->table.TABLE->has_data () && \
    ((void) (position && (*position = font->em_scalef_y (face->table.TABLE->ATTR + GET_VAR))), true))
#define GET_HEA_METRIC_X(TABLE, ATTR) \
  (face->table.TABLE->has_data () && \
    ((void) (position && (*position = font->em_scalef_x (HB_DUAL_GET (*face->table.TABLE, table->ATTR) + GET_VAR))), true))
#define GET_HEA_METRIC_Y(TABLE, ATTR) \
  (face->table.TABLE->has_data () && \
    ((void) (position && (*position = font->em_scalef_y (HB_DUAL_GET (*face->table.TABLE, table->ATTR) + GET_VAR))), true))
  case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_ASCENT:  return GET_METRIC_Y (OS2, usWinAscent);
  case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_DESCENT: return GET_METRIC_Y (OS2, usWinDescent);

  case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE:
  case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RUN:
  {
    unsigned mult = 1u;

    if (font->slant)
    {
      unsigned rise = HB_DUAL_GET (*face->table.hhea, table->caretSlopeRise);
      unsigned upem = face->get_upem ();
      mult = (rise && rise < upem) ? hb_min (upem / rise, 256u) : 1u;
    }

    if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE)
    {
      bool ret = GET_HEA_METRIC_Y (hhea, caretSlopeRise);

      if (position)
  *position = hb_clamp_to<hb_position_t> ((int64_t) *position * mult);

      return ret;
    }
    else
    {
      hb_position_t rise = 0;

      if (font->slant && position && GET_HEA_METRIC_Y (hhea, caretSlopeRise))
  rise = *position;

      bool ret = GET_HEA_METRIC_X (hhea, caretSlopeRun);

      if (position)
      {
  *position = hb_clamp_to<hb_position_t> ((int64_t) *position * mult);

  if (font->slant)
    *position = hb_saturate_add (*position,
               hb_clamp_to<hb_position_t> (roundf (mult * font->slant_xy * rise)));
      }

      return ret;
    }
  }
  case HB_OT_METRICS_TAG_HORIZONTAL_CARET_OFFSET:     return GET_HEA_METRIC_X (hhea, caretOffset);

#ifndef HB_NO_VERTICAL
  case HB_OT_METRICS_TAG_VERTICAL_CARET_RISE:         return GET_HEA_METRIC_X (vhea, caretSlopeRise);
  case HB_OT_METRICS_TAG_VERTICAL_CARET_RUN:          return GET_HEA_METRIC_Y (vhea, caretSlopeRun);
  case HB_OT_METRICS_TAG_VERTICAL_CARET_OFFSET:       return GET_HEA_METRIC_Y (vhea, caretOffset);
#endif
  case HB_OT_METRICS_TAG_X_HEIGHT:                    return GET_METRIC_Y (OS2->v2 (), sxHeight);
  case HB_OT_METRICS_TAG_CAP_HEIGHT:                  return GET_METRIC_Y (OS2->v2 (), sCapHeight);
  case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_SIZE:         return GET_METRIC_X (OS2, ySubscriptXSize);
  case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_SIZE:         return GET_METRIC_Y (OS2, ySubscriptYSize);
  case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_OFFSET:       return GET_METRIC_X (OS2, ySubscriptXOffset);
  case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_OFFSET:       return GET_METRIC_Y (OS2, ySubscriptYOffset);
  case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_SIZE:       return GET_METRIC_X (OS2, ySuperscriptXSize);
  case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_SIZE:       return GET_METRIC_Y (OS2, ySuperscriptYSize);
  case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_OFFSET:     return GET_METRIC_X (OS2, ySuperscriptXOffset);
  case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_OFFSET:     return GET_METRIC_Y (OS2, ySuperscriptYOffset);
  case HB_OT_METRICS_TAG_STRIKEOUT_SIZE:              return GET_METRIC_Y (OS2, yStrikeoutSize);
  case HB_OT_METRICS_TAG_STRIKEOUT_OFFSET:            return GET_METRIC_Y (OS2, yStrikeoutPosition);
  case HB_OT_METRICS_TAG_UNDERLINE_SIZE:              return GET_METRIC_Y (post->table, underlineThickness);
  case HB_OT_METRICS_TAG_UNDERLINE_OFFSET:            return GET_METRIC_Y (post->table, underlinePosition);

  /* Private tags */
  case _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_OS2:    return GET_METRIC_Y (OS2, sTypoAscender);
  case _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_HHEA:   return GET_HEA_METRIC_Y (hhea, ascender);
  case _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_OS2:   return GET_METRIC_Y (OS2, sTypoDescender);
  case _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_HHEA:  return GET_HEA_METRIC_Y (hhea, descender);
  case _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_OS2:    return GET_METRIC_Y (OS2, sTypoLineGap);
  case _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_HHEA:   return GET_HEA_METRIC_Y (hhea, lineGap);
#undef GET_HEA_METRIC_Y
#undef GET_HEA_METRIC_X
#undef GET_METRIC_Y
#undef GET_METRIC_X
#undef GET_VAR
  default:                                        return false;
  }
}

/**
 * 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 */)
{
  hb_font_extents_t font_extents;
  hb_codepoint_t glyph;
  hb_glyph_extents_t extents;

  if (hb_ot_metrics_get_position (font, metrics_tag, position))
    {
      if ((metrics_tag != HB_OT_METRICS_TAG_STRIKEOUT_SIZE &&
           metrics_tag != HB_OT_METRICS_TAG_UNDERLINE_SIZE) ||
          *position != 0)
        return;
    }

  switch (metrics_tag)
  {
  case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
  case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_ASCENT:
    hb_font_get_extents_for_direction (font, HB_DIRECTION_LTR, &font_extents);
    *position = font_extents.ascender;
    break;

  case HB_OT_METRICS_TAG_VERTICAL_ASCENDER:
    hb_font_get_extents_for_direction (font, HB_DIRECTION_TTB, &font_extents);
    *position = font_extents.ascender;
    break;

  case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
  case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_DESCENT:
    hb_font_get_extents_for_direction (font, HB_DIRECTION_LTR, &font_extents);
    *position = font_extents.descender;
    break;

  case HB_OT_METRICS_TAG_VERTICAL_DESCENDER:
    hb_font_get_extents_for_direction (font, HB_DIRECTION_TTB, &font_extents);
    *position = font_extents.ascender;
    break;

  case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
    hb_font_get_extents_for_direction (font, HB_DIRECTION_LTR, &font_extents);
    *position = font_extents.line_gap;
    break;

  case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP:
    hb_font_get_extents_for_direction (font, HB_DIRECTION_TTB, &font_extents);
    *position = font_extents.line_gap;
    break;

  case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE:
  case HB_OT_METRICS_TAG_VERTICAL_CARET_RISE:
    *position = 1;
    break;

  case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RUN:
  case HB_OT_METRICS_TAG_VERTICAL_CARET_RUN:
    *position = 0;
    break;

  case HB_OT_METRICS_TAG_HORIZONTAL_CARET_OFFSET:
  case HB_OT_METRICS_TAG_VERTICAL_CARET_OFFSET:
    *position = 0;
    break;

  case HB_OT_METRICS_TAG_X_HEIGHT:
    if (hb_font_get_nominal_glyph (font, 'x', &glyph) &&
        hb_font_get_glyph_extents (font, glyph, &extents))
      *position = extents.y_bearing;
    else
      *position = font->y_scale / 2;
    break;

  case HB_OT_METRICS_TAG_CAP_HEIGHT:
    if (hb_font_get_nominal_glyph (font, 'O', &glyph) &&
        hb_font_get_glyph_extents (font, glyph, &extents))
      *position = hb_clamp_to<hb_position_t> ((int64_t) extents.height +
                2 * (int64_t) extents.y_bearing);
    else
      *position = hb_clamp_to<hb_position_t> ((int64_t) font->y_scale * 2 / 3);
    break;

  case HB_OT_METRICS_TAG_STRIKEOUT_SIZE:
  case HB_OT_METRICS_TAG_UNDERLINE_SIZE:
    *position = font->y_scale / 18;
    break;

  case HB_OT_METRICS_TAG_STRIKEOUT_OFFSET:
    {
      hb_position_t ascender;
      hb_ot_metrics_get_position_with_fallback (font,
                                                HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER,
                                                &ascender);
      *position = ascender / 2;
    }
    break;

  case HB_OT_METRICS_TAG_UNDERLINE_OFFSET:
    *position = hb_saturate_neg (font->y_scale) / 18;
    break;

  case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_SIZE:
  case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_SIZE:
    *position = hb_clamp_to<hb_position_t> ((int64_t) font->x_scale * 10 / 12);
    break;

  case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_SIZE:
  case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_SIZE:
    *position = hb_clamp_to<hb_position_t> ((int64_t) font->y_scale * 10 / 12);
    break;

  case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_OFFSET:
  case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_OFFSET:
    *position = 0;
    break;

  case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_OFFSET:
  case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_OFFSET:
    *position = font->y_scale / 5;
    break;

  case _HB_OT_METRICS_TAG_MAX_VALUE:
  default:
    *position = 0;
    break;
  }
}

#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)
{
  return font->face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords);
}

/**
 * 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)
{
  return font->em_scalef_x (hb_ot_metrics_get_variation (font, 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)
{
  return font->em_scalef_y (hb_ot_metrics_get_variation (font, metrics_tag));
}
#endif

#endif

Coverage Report

Created: 2026-11-06 11:29

Line	Count	Source
1		/*
2		* Copyright © 2018-2019 Ebrahim Byagowi
3		*
4		* This is part of HarfBuzz, a text shaping library.
5		*
6		* Permission is hereby granted, without written agreement and without
7		* license or royalty fees, to use, copy, modify, and distribute this
8		* software and its documentation for any purpose, provided that the
9		* above copyright notice and the following two paragraphs appear in
10		* all copies of this software.
11		*
12		* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13		* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14		* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15		* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16		* DAMAGE.
17		*
18		* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19		* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20		* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
21		* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22		* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23		*/
24
25		#include "hb.hh"
26
27		#include "hb-ot-var-mvar-table.hh"
28		#include "hb-ot-gasp-table.hh" // Just so we compile it; unused otherwise.
29		#include "hb-ot-os2-table.hh"
30		#include "hb-ot-post-table.hh"
31		#include "hb-ot-hhea-table.hh"
32		#include "hb-ot-metrics.hh"
33		#include "hb-ot-face.hh"
34
35
36		/**
37		* SECTION:hb-ot-metrics
38		* @title: hb-ot-metrics
39		* @short_description: OpenType Metrics
40		* @include: hb-ot.h
41		*
42		* Functions for fetching metrics from fonts.
43		**/
44
45		static float
46		_fix_ascender_descender (float value, hb_ot_metrics_tag_t metrics_tag)
47	1.70M	{
48	1.70M	if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER \|\|
49	1.13M	metrics_tag == HB_OT_METRICS_TAG_VERTICAL_ASCENDER)
50	567k	return fabs ((double) value);
51	1.13M	if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER \|\|
52	567k	metrics_tag == HB_OT_METRICS_TAG_VERTICAL_DESCENDER)
53	567k	return -fabs ((double) value);
54	567k	return value;
55	1.13M	}
56
57		/* The common part of _get_position logic needed on hb-ot-font and here
58		to be able to have slim builds without the not always needed parts */
59		bool
60		_hb_ot_metrics_get_position_common (hb_font_t *font,
61		hb_ot_metrics_tag_t metrics_tag,
62		hb_position_t position / OUT. May be NULL. */)
63	1.70M	{
64	1.70M	hb_face_t *face = font->face;
65	1.70M	switch ((unsigned) metrics_tag)
66	1.70M	{
67	0	#ifndef HB_NO_VAR
68	1.70M	#define GET_VAR face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords)
69		#else
70		#define GET_VAR .0f
71		#endif
72	0	#define GET_METRIC_Y(TABLE, ATTR) \
73	94	(face->table.TABLE->has_data () && \
74	94	((void) (position && (*position = font->em_scalef_y (_fix_ascender_descender ( \
75	93	face->table.TABLE->ATTR + GET_VAR, metrics_tag)))), true))
76	0	#define GET_HEA_METRIC_X(TABLE, ATTR) \
77	0	(face->table.TABLE->has_data () && \
78	0	((void) (position && (*position = font->em_scalef_x (_fix_ascender_descender ( \
79	0	HB_DUAL_GET (*face->table.TABLE, table->ATTR) + GET_VAR, metrics_tag)))), true))
80	0	#define GET_HEA_METRIC_Y(TABLE, ATTR) \
81	1.70M	(face->table.TABLE->has_data () && \
82	1.70M	((void) (position && (*position = font->em_scalef_y (_fix_ascender_descender ( \
83	1.70M	HB_DUAL_GET (*face->table.TABLE, table->ATTR) + GET_VAR, metrics_tag)))), true))
84
85	567k	case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
86	567k	return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoAscender)) \|\|
87	567k	GET_HEA_METRIC_Y (hhea, ascender);
88	567k	case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
89	567k	return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoDescender)) \|\|
90	567k	GET_HEA_METRIC_Y (hhea, descender);
91	567k	case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
92	567k	return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoLineGap)) \|\|
93	567k	GET_HEA_METRIC_Y (hhea, lineGap);
94
95	0	#ifndef HB_NO_VERTICAL
96	0	case HB_OT_METRICS_TAG_VERTICAL_ASCENDER: return GET_HEA_METRIC_X (vhea, ascender);
97	0	case HB_OT_METRICS_TAG_VERTICAL_DESCENDER: return GET_HEA_METRIC_X (vhea, descender);
98	0	case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP: return GET_HEA_METRIC_X (vhea, lineGap);
99	0	#endif
100
101	0	#undef GET_HEA_METRIC_Y
102	0	#undef GET_HEA_METRIC_X
103	0	#undef GET_METRIC_Y
104	0	#undef GET_VAR
105	0	default: assert (0); return false;
106	1.70M	}
107	1.70M	}
108
109		#ifndef HB_NO_METRICS
110
111		#if 0
112		static bool
113		_get_gasp (hb_face_t face, float result, hb_ot_metrics_tag_t metrics_tag)
114		{
115		const OT::GaspRange& range = face->table.gasp->get_gasp_range (metrics_tag - HB_TAG ('g','s','p','0'));
116		if (&range == &Null (OT::GaspRange)) return false;
117		if (result) *result = range.rangeMaxPPEM + font->face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords);
118		return true;
119		}
120		#endif
121
122		/* Private tags for https://github.com/harfbuzz/harfbuzz/issues/1866 */
123	160k	#define _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_OS2 HB_TAG ('O','a','s','c')
124	172k	#define _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_HHEA HB_TAG ('H','a','s','c')
125	155k	#define _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_OS2 HB_TAG ('O','d','s','c')
126	167k	#define _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_HHEA HB_TAG ('H','d','s','c')
127	155k	#define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_OS2 HB_TAG ('O','l','g','p')
128	155k	#define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_HHEA HB_TAG ('H','l','g','p')
129
130		/**
131		* hb_ot_metrics_get_position:
132		* @font: an #hb_font_t object.
133		* @metrics_tag: tag of metrics value you like to fetch.
134		* @position: (out) (optional): result of metrics value from the font.
135		*
136		* Fetches metrics value corresponding to @metrics_tag from @font.
137		*
138		* Returns: Whether found the requested metrics in the font.
139		* Since: 2.6.0
140		**/
141		hb_bool_t
142		hb_ot_metrics_get_position (hb_font_t *font,
143		hb_ot_metrics_tag_t metrics_tag,
144		hb_position_t position / OUT. May be NULL. */)
145	2.52M	{
146	2.52M	hb_face_t *face = font->face;
147	2.52M	switch ((unsigned) metrics_tag)
148	2.52M	{
149	0	case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
150	0	case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
151	0	case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
152	0	case HB_OT_METRICS_TAG_VERTICAL_ASCENDER:
153	0	case HB_OT_METRICS_TAG_VERTICAL_DESCENDER:
154	0	case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP: return _hb_ot_metrics_get_position_common (font, metrics_tag, position);
155	0	#ifndef HB_NO_VAR
156	2.48M	#define GET_VAR hb_ot_metrics_get_variation (font, metrics_tag)
157		#else
158		#define GET_VAR 0
159		#endif
160	0	#define GET_METRIC_X(TABLE, ATTR) \
161	0	(face->table.TABLE->has_data () && \
162	0	((void) (position && (*position = font->em_scalef_x (face->table.TABLE->ATTR + GET_VAR))), true))
163	0	#define GET_METRIC_Y(TABLE, ATTR) \
164	2.03M	(face->table.TABLE->has_data () && \
165	2.03M	((void) (position && (*position = font->em_scalef_y (face->table.TABLE->ATTR + GET_VAR))), true))
166	0	#define GET_HEA_METRIC_X(TABLE, ATTR) \
167	0	(face->table.TABLE->has_data () && \
168	0	((void) (position && (position = font->em_scalef_x (HB_DUAL_GET (face->table.TABLE, table->ATTR) + GET_VAR))), true))
169	0	#define GET_HEA_METRIC_Y(TABLE, ATTR) \
170	495k	(face->table.TABLE->has_data () && \
171	495k	((void) (position && (position = font->em_scalef_y (HB_DUAL_GET (face->table.TABLE, table->ATTR) + GET_VAR))), true))
172	155k	case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_ASCENT: return GET_METRIC_Y (OS2, usWinAscent);
173	155k	case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_DESCENT: return GET_METRIC_Y (OS2, usWinDescent);
174
175	0	case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE:
176	0	case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RUN:
177	0	{
178	0	unsigned mult = 1u;
179
180	0	if (font->slant)
181	0	{
182	0	unsigned rise = HB_DUAL_GET (*face->table.hhea, table->caretSlopeRise);
183	0	unsigned upem = face->get_upem ();
184	0	mult = (rise && rise < upem) ? hb_min (upem / rise, 256u) : 1u;
185	0	}
186
187	0	if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE)
188	0	{
189	0	bool ret = GET_HEA_METRIC_Y (hhea, caretSlopeRise);
190
191	0	if (position)
192	0	position = hb_clamp_to<hb_position_t> ((int64_t) position * mult);
193
194	0	return ret;
195	0	}
196	0	else
197	0	{
198	0	hb_position_t rise = 0;
199
200	0	if (font->slant && position && GET_HEA_METRIC_Y (hhea, caretSlopeRise))
201	0	rise = *position;
202
203	0	bool ret = GET_HEA_METRIC_X (hhea, caretSlopeRun);
204
205	0	if (position)
206	0	{
207	0	position = hb_clamp_to<hb_position_t> ((int64_t) position * mult);
208
209	0	if (font->slant)
210	0	position = hb_saturate_add (position,
211	0	hb_clamp_to<hb_position_t> (roundf (mult * font->slant_xy * rise)));
212	0	}
213
214	0	return ret;
215	0	}
216	0	}
217	0	case HB_OT_METRICS_TAG_HORIZONTAL_CARET_OFFSET: return GET_HEA_METRIC_X (hhea, caretOffset);
218
219	0	#ifndef HB_NO_VERTICAL
220	0	case HB_OT_METRICS_TAG_VERTICAL_CARET_RISE: return GET_HEA_METRIC_X (vhea, caretSlopeRise);
221	0	case HB_OT_METRICS_TAG_VERTICAL_CARET_RUN: return GET_HEA_METRIC_Y (vhea, caretSlopeRun);
222	0	case HB_OT_METRICS_TAG_VERTICAL_CARET_OFFSET: return GET_HEA_METRIC_Y (vhea, caretOffset);
223	0	#endif
224	0	case HB_OT_METRICS_TAG_X_HEIGHT: return GET_METRIC_Y (OS2->v2 (), sxHeight);
225	12.5k	case HB_OT_METRICS_TAG_CAP_HEIGHT: return GET_METRIC_Y (OS2->v2 (), sCapHeight);
226	0	case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_SIZE: return GET_METRIC_X (OS2, ySubscriptXSize);
227	0	case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_SIZE: return GET_METRIC_Y (OS2, ySubscriptYSize);
228	0	case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_OFFSET: return GET_METRIC_X (OS2, ySubscriptXOffset);
229	0	case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_OFFSET: return GET_METRIC_Y (OS2, ySubscriptYOffset);
230	0	case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_SIZE: return GET_METRIC_X (OS2, ySuperscriptXSize);
231	0	case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_SIZE: return GET_METRIC_Y (OS2, ySuperscriptYSize);
232	0	case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_OFFSET: return GET_METRIC_X (OS2, ySuperscriptXOffset);
233	0	case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_OFFSET: return GET_METRIC_Y (OS2, ySuperscriptYOffset);
234	302k	case HB_OT_METRICS_TAG_STRIKEOUT_SIZE: return GET_METRIC_Y (OS2, yStrikeoutSize);
235	302k	case HB_OT_METRICS_TAG_STRIKEOUT_OFFSET: return GET_METRIC_Y (OS2, yStrikeoutPosition);
236	327k	case HB_OT_METRICS_TAG_UNDERLINE_SIZE: return GET_METRIC_Y (post->table, underlineThickness);
237	302k	case HB_OT_METRICS_TAG_UNDERLINE_OFFSET: return GET_METRIC_Y (post->table, underlinePosition);
238
239		/* Private tags */
240	160k	case _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_OS2: return GET_METRIC_Y (OS2, sTypoAscender);
241	172k	case _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_HHEA: return GET_HEA_METRIC_Y (hhea, ascender);
242	155k	case _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_OS2: return GET_METRIC_Y (OS2, sTypoDescender);
243	167k	case _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_HHEA: return GET_HEA_METRIC_Y (hhea, descender);
244	155k	case _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_OS2: return GET_METRIC_Y (OS2, sTypoLineGap);
245	155k	case _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_HHEA: return GET_HEA_METRIC_Y (hhea, lineGap);
246	0	#undef GET_HEA_METRIC_Y
247	0	#undef GET_HEA_METRIC_X
248	0	#undef GET_METRIC_Y
249	0	#undef GET_METRIC_X
250	0	#undef GET_VAR
251	0	default: return false;
252	2.52M	}
253	2.52M	}
254
255		/**
256		* hb_ot_metrics_get_position_with_fallback:
257		* @font: an #hb_font_t object.
258		* @metrics_tag: tag of metrics value you like to fetch.
259		* @position: (out) (optional): result of metrics value from the font.
260		*
261		* Fetches metrics value corresponding to @metrics_tag from @font,
262		* and synthesizes a value if it the value is missing in the font.
263		*
264		* Since: 4.0.0
265		**/
266		void
267		hb_ot_metrics_get_position_with_fallback (hb_font_t *font,
268		hb_ot_metrics_tag_t metrics_tag,
269		hb_position_t position / OUT */)
270	0	{
271	0	hb_font_extents_t font_extents;
272	0	hb_codepoint_t glyph;
273	0	hb_glyph_extents_t extents;
274
275	0	if (hb_ot_metrics_get_position (font, metrics_tag, position))
276	0	{
277	0	if ((metrics_tag != HB_OT_METRICS_TAG_STRIKEOUT_SIZE &&
278	0	metrics_tag != HB_OT_METRICS_TAG_UNDERLINE_SIZE) \|\|
279	0	*position != 0)
280	0	return;
281	0	}
282
283	0	switch (metrics_tag)
284	0	{
285	0	case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
286	0	case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_ASCENT:
287	0	hb_font_get_extents_for_direction (font, HB_DIRECTION_LTR, &font_extents);
288	0	*position = font_extents.ascender;
289	0	break;
290
291	0	case HB_OT_METRICS_TAG_VERTICAL_ASCENDER:
292	0	hb_font_get_extents_for_direction (font, HB_DIRECTION_TTB, &font_extents);
293	0	*position = font_extents.ascender;
294	0	break;
295
296	0	case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
297	0	case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_DESCENT:
298	0	hb_font_get_extents_for_direction (font, HB_DIRECTION_LTR, &font_extents);
299	0	*position = font_extents.descender;
300	0	break;
301
302	0	case HB_OT_METRICS_TAG_VERTICAL_DESCENDER:
303	0	hb_font_get_extents_for_direction (font, HB_DIRECTION_TTB, &font_extents);
304	0	*position = font_extents.ascender;
305	0	break;
306
307	0	case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
308	0	hb_font_get_extents_for_direction (font, HB_DIRECTION_LTR, &font_extents);
309	0	*position = font_extents.line_gap;
310	0	break;
311
312	0	case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP:
313	0	hb_font_get_extents_for_direction (font, HB_DIRECTION_TTB, &font_extents);
314	0	*position = font_extents.line_gap;
315	0	break;
316
317	0	case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE:
318	0	case HB_OT_METRICS_TAG_VERTICAL_CARET_RISE:
319	0	*position = 1;
320	0	break;
321
322	0	case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RUN:
323	0	case HB_OT_METRICS_TAG_VERTICAL_CARET_RUN:
324	0	*position = 0;
325	0	break;
326
327	0	case HB_OT_METRICS_TAG_HORIZONTAL_CARET_OFFSET:
328	0	case HB_OT_METRICS_TAG_VERTICAL_CARET_OFFSET:
329	0	*position = 0;
330	0	break;
331
332	0	case HB_OT_METRICS_TAG_X_HEIGHT:
333	0	if (hb_font_get_nominal_glyph (font, 'x', &glyph) &&
334	0	hb_font_get_glyph_extents (font, glyph, &extents))
335	0	*position = extents.y_bearing;
336	0	else
337	0	*position = font->y_scale / 2;
338	0	break;
339
340	0	case HB_OT_METRICS_TAG_CAP_HEIGHT:
341	0	if (hb_font_get_nominal_glyph (font, 'O', &glyph) &&
342	0	hb_font_get_glyph_extents (font, glyph, &extents))
343	0	*position = hb_clamp_to<hb_position_t> ((int64_t) extents.height +
344	0	2 * (int64_t) extents.y_bearing);
345	0	else
346	0	position = hb_clamp_to<hb_position_t> ((int64_t) font->y_scale 2 / 3);
347	0	break;
348
349	0	case HB_OT_METRICS_TAG_STRIKEOUT_SIZE:
350	0	case HB_OT_METRICS_TAG_UNDERLINE_SIZE:
351	0	*position = font->y_scale / 18;
352	0	break;
353
354	0	case HB_OT_METRICS_TAG_STRIKEOUT_OFFSET:
355	0	{
356	0	hb_position_t ascender;
357	0	hb_ot_metrics_get_position_with_fallback (font,
358	0	HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER,
359	0	&ascender);
360	0	*position = ascender / 2;
361	0	}
362	0	break;
363
364	0	case HB_OT_METRICS_TAG_UNDERLINE_OFFSET:
365	0	*position = hb_saturate_neg (font->y_scale) / 18;
366	0	break;
367
368	0	case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_SIZE:
369	0	case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_SIZE:
370	0	position = hb_clamp_to<hb_position_t> ((int64_t) font->x_scale 10 / 12);
371	0	break;
372
373	0	case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_SIZE:
374	0	case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_SIZE:
375	0	position = hb_clamp_to<hb_position_t> ((int64_t) font->y_scale 10 / 12);
376	0	break;
377
378	0	case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_OFFSET:
379	0	case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_OFFSET:
380	0	*position = 0;
381	0	break;
382
383	0	case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_OFFSET:
384	0	case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_OFFSET:
385	0	*position = font->y_scale / 5;
386	0	break;
387
388	0	case _HB_OT_METRICS_TAG_MAX_VALUE:
389	0	default:
390	0	*position = 0;
391	0	break;
392	0	}
393	0	}
394
395		#ifndef HB_NO_VAR
396		/**
397		* hb_ot_metrics_get_variation:
398		* @font: an #hb_font_t object.
399		* @metrics_tag: tag of metrics value you like to fetch.
400		*
401		* Fetches metrics value corresponding to @metrics_tag from @font with the
402		* current font variation settings applied.
403		*
404		* Returns: The requested metric value.
405		*
406		* Since: 2.6.0
407		**/
408		float
409		hb_ot_metrics_get_variation (hb_font_t *font, hb_ot_metrics_tag_t metrics_tag)
410	2.48M	{
411	2.48M	return font->face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords);
412	2.48M	}
413
414		/**
415		* hb_ot_metrics_get_x_variation:
416		* @font: an #hb_font_t object.
417		* @metrics_tag: tag of metrics value you like to fetch.
418		*
419		* Fetches horizontal metrics value corresponding to @metrics_tag from @font
420		* with the current font variation settings applied.
421		*
422		* Returns: The requested metric value.
423		*
424		* Since: 2.6.0
425		**/
426		hb_position_t
427		hb_ot_metrics_get_x_variation (hb_font_t *font, hb_ot_metrics_tag_t metrics_tag)
428	0	{
429	0	return font->em_scalef_x (hb_ot_metrics_get_variation (font, metrics_tag));
430	0	}
431
432		/**
433		* hb_ot_metrics_get_y_variation:
434		* @font: an #hb_font_t object.
435		* @metrics_tag: tag of metrics value you like to fetch.
436		*
437		* Fetches vertical metrics value corresponding to @metrics_tag from @font with
438		* the current font variation settings applied.
439		*
440		* Returns: The requested metric value.
441		*
442		* Since: 2.6.0
443		**/
444		hb_position_t
445		hb_ot_metrics_get_y_variation (hb_font_t *font, hb_ot_metrics_tag_t metrics_tag)
446	0	{
447	0	return font->em_scalef_y (hb_ot_metrics_get_variation (font, metrics_tag));
448	0	}
449		#endif
450
451		#endif