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harfbuzz/src/hb-ot-metrics.cc

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/*
* 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_X(TABLE, ATTR) \
(face->table.TABLE->has_data () && \
(position && (*position = font->em_scalef_x (_fix_ascender_descender ( \
face->table.TABLE->ATTR + GET_VAR, metrics_tag))), true))
#define GET_METRIC_Y(TABLE, ATTR) \
(face->table.TABLE->has_data () && \
(position && (*position = font->em_scalef_y (_fix_ascender_descender ( \
face->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_METRIC_Y (hhea, ascender);
case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoDescender)) ||
GET_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_METRIC_Y (hhea, lineGap);
#ifndef HB_NO_VERTICAL
case HB_OT_METRICS_TAG_VERTICAL_ASCENDER: return GET_METRIC_X (vhea, ascender);
case HB_OT_METRICS_TAG_VERTICAL_DESCENDER: return GET_METRIC_X (vhea, descender);
case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP: return GET_METRIC_X (vhea, lineGap);
#endif
#undef GET_METRIC_Y
#undef GET_METRIC_X
#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 () && \
(position && (*position = font->em_scalef_x (face->table.TABLE->ATTR + GET_VAR)), true))
#define GET_METRIC_Y(TABLE, ATTR) \
(face->table.TABLE->has_data () && \
(position && (*position = font->em_scalef_y (face->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 = face->table.hhea->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_METRIC_Y (hhea, caretSlopeRise);
if (position)
*position *= mult;
return ret;
}
else
{
hb_position_t rise = 0;
if (font->slant && position && GET_METRIC_Y (hhea, caretSlopeRise))
rise = *position;
bool ret = GET_METRIC_X (hhea, caretSlopeRun);
if (position)
{
*position *= mult;
if (font->slant)
*position += _hb_roundf (mult * font->slant_xy * rise);
}
return ret;
}
}
case HB_OT_METRICS_TAG_HORIZONTAL_CARET_OFFSET: return GET_METRIC_X (hhea, caretOffset);
#ifndef HB_NO_VERTICAL
case HB_OT_METRICS_TAG_VERTICAL_CARET_RISE: return GET_METRIC_X (vhea, caretSlopeRise);
case HB_OT_METRICS_TAG_VERTICAL_CARET_RUN: return GET_METRIC_Y (vhea, caretSlopeRun);
case HB_OT_METRICS_TAG_VERTICAL_CARET_OFFSET: return GET_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_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_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_METRIC_Y (hhea, lineGap);
#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 = extents.height + 2 * extents.y_bearing;
else
*position = 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 = - font->y_scale / 18;
break;
case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_SIZE:
case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_SIZE:
*position = 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 = 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
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