kc3-lang/harfbuzz/src/hb-ot-metrics.cc

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• Hash : 08269408
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  Date : 2020-12-23T00:45:39
  

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• 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)
  {
    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
  

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