436 lines
15 KiB
C++
436 lines
15 KiB
C++
/*
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* Copyright © 2018-2019 Ebrahim Byagowi
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*
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* This is part of HarfBuzz, a text shaping library.
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*
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* Permission is hereby granted, without written agreement and without
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* license or royalty fees, to use, copy, modify, and distribute this
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* software and its documentation for any purpose, provided that the
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* above copyright notice and the following two paragraphs appear in
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* all copies of this software.
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*
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*/
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#include "hb.hh"
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#include "hb-ot-var-mvar-table.hh"
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#include "hb-ot-gasp-table.hh" // Just so we compile it; unused otherwise.
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#include "hb-ot-os2-table.hh"
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#include "hb-ot-post-table.hh"
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#include "hb-ot-hhea-table.hh"
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#include "hb-ot-metrics.hh"
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#include "hb-ot-face.hh"
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/**
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* SECTION:hb-ot-metrics
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* @title: hb-ot-metrics
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* @short_description: OpenType Metrics
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* @include: hb-ot.h
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*
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* Functions for fetching metrics from fonts.
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**/
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static float
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_fix_ascender_descender (float value, hb_ot_metrics_tag_t metrics_tag)
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{
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if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER ||
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metrics_tag == HB_OT_METRICS_TAG_VERTICAL_ASCENDER)
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return fabs ((double) value);
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if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER ||
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metrics_tag == HB_OT_METRICS_TAG_VERTICAL_DESCENDER)
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return -fabs ((double) value);
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return value;
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}
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/* The common part of _get_position logic needed on hb-ot-font and here
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to be able to have slim builds without the not always needed parts */
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bool
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_hb_ot_metrics_get_position_common (hb_font_t *font,
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hb_ot_metrics_tag_t metrics_tag,
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hb_position_t *position /* OUT. May be NULL. */)
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{
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hb_face_t *face = font->face;
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switch ((unsigned) metrics_tag)
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{
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#ifndef HB_NO_VAR
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#define GET_VAR face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords)
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#else
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#define GET_VAR .0f
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#endif
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#define GET_METRIC_X(TABLE, ATTR) \
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(face->table.TABLE->has_data () && \
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((void) (position && (*position = font->em_scalef_x (_fix_ascender_descender ( \
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face->table.TABLE->ATTR + GET_VAR, metrics_tag)))), true))
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#define GET_METRIC_Y(TABLE, ATTR) \
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(face->table.TABLE->has_data () && \
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((void) (position && (*position = font->em_scalef_y (_fix_ascender_descender ( \
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face->table.TABLE->ATTR + GET_VAR, metrics_tag)))), true))
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case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
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return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoAscender)) ||
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GET_METRIC_Y (hhea, ascender);
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case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
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return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoDescender)) ||
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GET_METRIC_Y (hhea, descender);
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case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
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return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoLineGap)) ||
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GET_METRIC_Y (hhea, lineGap);
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#ifndef HB_NO_VERTICAL
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case HB_OT_METRICS_TAG_VERTICAL_ASCENDER: return GET_METRIC_X (vhea, ascender);
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case HB_OT_METRICS_TAG_VERTICAL_DESCENDER: return GET_METRIC_X (vhea, descender);
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case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP: return GET_METRIC_X (vhea, lineGap);
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#endif
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#undef GET_METRIC_Y
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#undef GET_METRIC_X
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#undef GET_VAR
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default: assert (0); return false;
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}
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}
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#ifndef HB_NO_METRICS
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#if 0
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static bool
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_get_gasp (hb_face_t *face, float *result, hb_ot_metrics_tag_t metrics_tag)
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{
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const OT::GaspRange& range = face->table.gasp->get_gasp_range (metrics_tag - HB_TAG ('g','s','p','0'));
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if (&range == &Null (OT::GaspRange)) return false;
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if (result) *result = range.rangeMaxPPEM + font->face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords);
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return true;
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}
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#endif
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/* Private tags for https://github.com/harfbuzz/harfbuzz/issues/1866 */
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#define _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_OS2 HB_TAG ('O','a','s','c')
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#define _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_HHEA HB_TAG ('H','a','s','c')
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#define _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_OS2 HB_TAG ('O','d','s','c')
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#define _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_HHEA HB_TAG ('H','d','s','c')
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#define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_OS2 HB_TAG ('O','l','g','p')
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#define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_HHEA HB_TAG ('H','l','g','p')
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/**
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* hb_ot_metrics_get_position:
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* @font: an #hb_font_t object.
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* @metrics_tag: tag of metrics value you like to fetch.
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* @position: (out) (optional): result of metrics value from the font.
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*
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* Fetches metrics value corresponding to @metrics_tag from @font.
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*
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* Returns: Whether found the requested metrics in the font.
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* Since: 2.6.0
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**/
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hb_bool_t
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hb_ot_metrics_get_position (hb_font_t *font,
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hb_ot_metrics_tag_t metrics_tag,
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hb_position_t *position /* OUT. May be NULL. */)
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{
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hb_face_t *face = font->face;
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switch ((unsigned) metrics_tag)
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{
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case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
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case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
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case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
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case HB_OT_METRICS_TAG_VERTICAL_ASCENDER:
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case HB_OT_METRICS_TAG_VERTICAL_DESCENDER:
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case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP: return _hb_ot_metrics_get_position_common (font, metrics_tag, position);
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#ifndef HB_NO_VAR
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#define GET_VAR hb_ot_metrics_get_variation (font, metrics_tag)
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#else
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#define GET_VAR 0
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#endif
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#define GET_METRIC_X(TABLE, ATTR) \
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(face->table.TABLE->has_data () && \
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((void) (position && (*position = font->em_scalef_x (face->table.TABLE->ATTR + GET_VAR))), true))
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#define GET_METRIC_Y(TABLE, ATTR) \
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(face->table.TABLE->has_data () && \
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((void) (position && (*position = font->em_scalef_y (face->table.TABLE->ATTR + GET_VAR))), true))
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case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_ASCENT: return GET_METRIC_Y (OS2, usWinAscent);
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case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_DESCENT: return GET_METRIC_Y (OS2, usWinDescent);
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case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE:
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case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RUN:
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{
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unsigned mult = 1u;
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if (font->slant)
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{
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unsigned rise = face->table.hhea->caretSlopeRise;
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unsigned upem = face->get_upem ();
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mult = (rise && rise < upem) ? hb_min (upem / rise, 256u) : 1u;
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}
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if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE)
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{
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bool ret = GET_METRIC_Y (hhea, caretSlopeRise);
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if (position)
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*position *= mult;
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return ret;
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}
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else
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{
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hb_position_t rise = 0;
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if (font->slant && position && GET_METRIC_Y (hhea, caretSlopeRise))
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rise = *position;
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bool ret = GET_METRIC_X (hhea, caretSlopeRun);
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if (position)
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{
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*position *= mult;
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if (font->slant)
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*position += _hb_roundf (mult * font->slant_xy * rise);
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}
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return ret;
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}
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}
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case HB_OT_METRICS_TAG_HORIZONTAL_CARET_OFFSET: return GET_METRIC_X (hhea, caretOffset);
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#ifndef HB_NO_VERTICAL
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case HB_OT_METRICS_TAG_VERTICAL_CARET_RISE: return GET_METRIC_X (vhea, caretSlopeRise);
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case HB_OT_METRICS_TAG_VERTICAL_CARET_RUN: return GET_METRIC_Y (vhea, caretSlopeRun);
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case HB_OT_METRICS_TAG_VERTICAL_CARET_OFFSET: return GET_METRIC_Y (vhea, caretOffset);
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#endif
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case HB_OT_METRICS_TAG_X_HEIGHT: return GET_METRIC_Y (OS2->v2 (), sxHeight);
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case HB_OT_METRICS_TAG_CAP_HEIGHT: return GET_METRIC_Y (OS2->v2 (), sCapHeight);
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case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_SIZE: return GET_METRIC_X (OS2, ySubscriptXSize);
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case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_SIZE: return GET_METRIC_Y (OS2, ySubscriptYSize);
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case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_OFFSET: return GET_METRIC_X (OS2, ySubscriptXOffset);
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case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_OFFSET: return GET_METRIC_Y (OS2, ySubscriptYOffset);
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case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_SIZE: return GET_METRIC_X (OS2, ySuperscriptXSize);
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case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_SIZE: return GET_METRIC_Y (OS2, ySuperscriptYSize);
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case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_OFFSET: return GET_METRIC_X (OS2, ySuperscriptXOffset);
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case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_OFFSET: return GET_METRIC_Y (OS2, ySuperscriptYOffset);
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case HB_OT_METRICS_TAG_STRIKEOUT_SIZE: return GET_METRIC_Y (OS2, yStrikeoutSize);
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case HB_OT_METRICS_TAG_STRIKEOUT_OFFSET: return GET_METRIC_Y (OS2, yStrikeoutPosition);
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case HB_OT_METRICS_TAG_UNDERLINE_SIZE: return GET_METRIC_Y (post->table, underlineThickness);
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case HB_OT_METRICS_TAG_UNDERLINE_OFFSET: return GET_METRIC_Y (post->table, underlinePosition);
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/* Private tags */
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case _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_OS2: return GET_METRIC_Y (OS2, sTypoAscender);
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case _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_HHEA: return GET_METRIC_Y (hhea, ascender);
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case _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_OS2: return GET_METRIC_Y (OS2, sTypoDescender);
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case _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_HHEA: return GET_METRIC_Y (hhea, descender);
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case _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_OS2: return GET_METRIC_Y (OS2, sTypoLineGap);
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case _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_HHEA: return GET_METRIC_Y (hhea, lineGap);
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#undef GET_METRIC_Y
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#undef GET_METRIC_X
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#undef GET_VAR
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default: return false;
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}
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}
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/**
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* hb_ot_metrics_get_position_with_fallback:
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* @font: an #hb_font_t object.
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* @metrics_tag: tag of metrics value you like to fetch.
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* @position: (out) (optional): result of metrics value from the font.
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*
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* Fetches metrics value corresponding to @metrics_tag from @font,
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* and synthesizes a value if it the value is missing in the font.
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*
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* Since: 4.0.0
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**/
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void
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hb_ot_metrics_get_position_with_fallback (hb_font_t *font,
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hb_ot_metrics_tag_t metrics_tag,
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hb_position_t *position /* OUT */)
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{
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hb_font_extents_t font_extents;
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hb_codepoint_t glyph;
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hb_glyph_extents_t extents;
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if (hb_ot_metrics_get_position (font, metrics_tag, position))
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{
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if ((metrics_tag != HB_OT_METRICS_TAG_STRIKEOUT_SIZE &&
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metrics_tag != HB_OT_METRICS_TAG_UNDERLINE_SIZE) ||
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*position != 0)
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return;
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}
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switch (metrics_tag)
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{
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case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
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case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_ASCENT:
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hb_font_get_extents_for_direction (font, HB_DIRECTION_LTR, &font_extents);
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*position = font_extents.ascender;
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break;
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case HB_OT_METRICS_TAG_VERTICAL_ASCENDER:
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hb_font_get_extents_for_direction (font, HB_DIRECTION_TTB, &font_extents);
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*position = font_extents.ascender;
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break;
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case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
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case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_DESCENT:
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hb_font_get_extents_for_direction (font, HB_DIRECTION_LTR, &font_extents);
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*position = font_extents.descender;
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break;
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case HB_OT_METRICS_TAG_VERTICAL_DESCENDER:
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hb_font_get_extents_for_direction (font, HB_DIRECTION_TTB, &font_extents);
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*position = font_extents.ascender;
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break;
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case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
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hb_font_get_extents_for_direction (font, HB_DIRECTION_LTR, &font_extents);
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*position = font_extents.line_gap;
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break;
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case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP:
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hb_font_get_extents_for_direction (font, HB_DIRECTION_TTB, &font_extents);
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*position = font_extents.line_gap;
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break;
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case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE:
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case HB_OT_METRICS_TAG_VERTICAL_CARET_RISE:
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*position = 1;
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break;
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case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RUN:
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case HB_OT_METRICS_TAG_VERTICAL_CARET_RUN:
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*position = 0;
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break;
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case HB_OT_METRICS_TAG_HORIZONTAL_CARET_OFFSET:
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case HB_OT_METRICS_TAG_VERTICAL_CARET_OFFSET:
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*position = 0;
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break;
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case HB_OT_METRICS_TAG_X_HEIGHT:
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if (hb_font_get_nominal_glyph (font, 'x', &glyph) &&
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hb_font_get_glyph_extents (font, glyph, &extents))
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*position = extents.y_bearing;
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else
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*position = font->y_scale / 2;
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break;
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case HB_OT_METRICS_TAG_CAP_HEIGHT:
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if (hb_font_get_nominal_glyph (font, 'O', &glyph) &&
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hb_font_get_glyph_extents (font, glyph, &extents))
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*position = extents.height + 2 * extents.y_bearing;
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else
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*position = font->y_scale * 2 / 3;
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break;
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case HB_OT_METRICS_TAG_STRIKEOUT_SIZE:
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case HB_OT_METRICS_TAG_UNDERLINE_SIZE:
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*position = font->y_scale / 18;
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break;
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case HB_OT_METRICS_TAG_STRIKEOUT_OFFSET:
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{
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hb_position_t ascender;
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hb_ot_metrics_get_position_with_fallback (font,
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HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER,
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&ascender);
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*position = ascender / 2;
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}
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break;
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case HB_OT_METRICS_TAG_UNDERLINE_OFFSET:
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*position = - font->y_scale / 18;
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break;
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case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_SIZE:
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case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_SIZE:
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*position = font->x_scale * 10 / 12;
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break;
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case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_SIZE:
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case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_SIZE:
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*position = font->y_scale * 10 / 12;
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break;
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case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_OFFSET:
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case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_OFFSET:
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*position = 0;
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break;
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case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_OFFSET:
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case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_OFFSET:
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*position = font->y_scale / 5;
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break;
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case _HB_OT_METRICS_TAG_MAX_VALUE:
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default:
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*position = 0;
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break;
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}
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}
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#ifndef HB_NO_VAR
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/**
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* hb_ot_metrics_get_variation:
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* @font: an #hb_font_t object.
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* @metrics_tag: tag of metrics value you like to fetch.
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*
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* Fetches metrics value corresponding to @metrics_tag from @font with the
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* current font variation settings applied.
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*
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* Returns: The requested metric value.
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*
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* Since: 2.6.0
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**/
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float
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hb_ot_metrics_get_variation (hb_font_t *font, hb_ot_metrics_tag_t metrics_tag)
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{
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return font->face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords);
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}
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/**
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* hb_ot_metrics_get_x_variation:
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* @font: an #hb_font_t object.
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* @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
|