harfbuzz-sys 0.3.4

Rust bindings to the HarfBuzz text shaping engine
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231

/*
 * 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