harfbuzz/src/hb-ot-metrics.cc
Behdad Esfahbod 6461143b44 2.6.0
2019-08-13 22:20:54 -07:00

232 lines
9.5 KiB
C++

/*
* 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"
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);
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);
#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: a #hb_font_t object.
* @metrics_tag: tag of metrics value you like to fetch.
* @position: (out) (optional): result of metrics value from the font.
*
* It fetches metrics value corresponding to a given tag from a 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: return GET_METRIC_Y (hhea, caretSlopeRise);
case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RUN: return GET_METRIC_X (hhea, caretSlopeRun);
case HB_OT_METRICS_TAG_HORIZONTAL_CARET_OFFSET: return GET_METRIC_X (hhea, caretOffset);
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);
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;
}
}
#ifndef HB_NO_VAR
/**
* hb_ot_metrics_get_variation:
* @font:
* @metrics_tag:
*
* Returns:
*
* 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:
* @metrics_tag:
*
* Returns:
*
* 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:
* @metrics_tag:
*
* Returns:
*
* 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