1 /*
2  * Copyright © 2018-2019  Ebrahim Byagowi
3  *
4  *  This is part of HarfBuzz, a text shaping library.
5  *
6  * Permission is hereby granted, without written agreement and without
7  * license or royalty fees, to use, copy, modify, and distribute this
8  * software and its documentation for any purpose, provided that the
9  * above copyright notice and the following two paragraphs appear in
10  * all copies of this software.
11  *
12  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16  * DAMAGE.
17  *
18  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
21  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23  */
24 
25 #include "hb.hh"
26 
27 #include "hb-ot-var-mvar-table.hh"
28 #include "hb-ot-gasp-table.hh" // Just so we compile it; unused otherwise.
29 #include "hb-ot-os2-table.hh"
30 #include "hb-ot-post-table.hh"
31 #include "hb-ot-hhea-table.hh"
32 #include "hb-ot-metrics.hh"
33 #include "hb-ot-face.hh"
34 
35 
36 static float
_fix_ascender_descender(float value,hb_ot_metrics_tag_t metrics_tag)37 _fix_ascender_descender (float value, hb_ot_metrics_tag_t metrics_tag)
38 {
39   if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER ||
40       metrics_tag == HB_OT_METRICS_TAG_VERTICAL_ASCENDER)
41     return fabs ((double) value);
42   if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER ||
43       metrics_tag == HB_OT_METRICS_TAG_VERTICAL_DESCENDER)
44     return -fabs ((double) value);
45   return value;
46 }
47 
48 /* The common part of _get_position logic needed on hb-ot-font and here
49    to be able to have slim builds without the not always needed parts */
50 bool
_hb_ot_metrics_get_position_common(hb_font_t * font,hb_ot_metrics_tag_t metrics_tag,hb_position_t * position)51 _hb_ot_metrics_get_position_common (hb_font_t           *font,
52 				    hb_ot_metrics_tag_t  metrics_tag,
53 				    hb_position_t       *position     /* OUT.  May be NULL. */)
54 {
55   hb_face_t *face = font->face;
56   switch ((unsigned) metrics_tag)
57   {
58 #ifndef HB_NO_VAR
59 #define GET_VAR face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords)
60 #else
61 #define GET_VAR .0f
62 #endif
63 #define GET_METRIC_X(TABLE, ATTR) \
64   (face->table.TABLE->has_data () && \
65     (position && (*position = font->em_scalef_x (_fix_ascender_descender ( \
66       face->table.TABLE->ATTR + GET_VAR, metrics_tag))), true))
67 #define GET_METRIC_Y(TABLE, ATTR) \
68   (face->table.TABLE->has_data () && \
69     (position && (*position = font->em_scalef_y (_fix_ascender_descender ( \
70       face->table.TABLE->ATTR + GET_VAR, metrics_tag))), true))
71   case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
72     return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoAscender)) ||
73 	   GET_METRIC_Y (hhea, ascender);
74   case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
75     return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoDescender)) ||
76 	   GET_METRIC_Y (hhea, descender);
77   case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
78     return (face->table.OS2->use_typo_metrics () && GET_METRIC_Y (OS2, sTypoLineGap)) ||
79 	   GET_METRIC_Y (hhea, lineGap);
80   case HB_OT_METRICS_TAG_VERTICAL_ASCENDER:  return GET_METRIC_X (vhea, ascender);
81   case HB_OT_METRICS_TAG_VERTICAL_DESCENDER: return GET_METRIC_X (vhea, descender);
82   case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP:  return GET_METRIC_X (vhea, lineGap);
83 #undef GET_METRIC_Y
84 #undef GET_METRIC_X
85 #undef GET_VAR
86   default:                               assert (0); return false;
87   }
88 }
89 
90 #ifndef HB_NO_METRICS
91 
92 #if 0
93 static bool
94 _get_gasp (hb_face_t *face, float *result, hb_ot_metrics_tag_t metrics_tag)
95 {
96   const OT::GaspRange& range = face->table.gasp->get_gasp_range (metrics_tag - HB_TAG ('g','s','p','0'));
97   if (&range == &Null (OT::GaspRange)) return false;
98   if (result) *result = range.rangeMaxPPEM + font->face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords);
99   return true;
100 }
101 #endif
102 
103 /* Private tags for https://github.com/harfbuzz/harfbuzz/issues/1866 */
104 #define _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_OS2   HB_TAG ('O','a','s','c')
105 #define _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_HHEA  HB_TAG ('H','a','s','c')
106 #define _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_OS2  HB_TAG ('O','d','s','c')
107 #define _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_HHEA HB_TAG ('H','d','s','c')
108 #define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_OS2   HB_TAG ('O','l','g','p')
109 #define _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_HHEA  HB_TAG ('H','l','g','p')
110 
111 /**
112  * hb_ot_metrics_get_position:
113  * @font: a #hb_font_t object.
114  * @metrics_tag: tag of metrics value you like to fetch.
115  * @position: (out) (optional): result of metrics value from the font.
116  *
117  * It fetches metrics value corresponding to a given tag from a font.
118  *
119  * Returns: Whether found the requested metrics in the font.
120  * Since: 2.6.0
121  **/
122 hb_bool_t
hb_ot_metrics_get_position(hb_font_t * font,hb_ot_metrics_tag_t metrics_tag,hb_position_t * position)123 hb_ot_metrics_get_position (hb_font_t           *font,
124 			    hb_ot_metrics_tag_t  metrics_tag,
125 			    hb_position_t       *position     /* OUT.  May be NULL. */)
126 {
127   hb_face_t *face = font->face;
128   switch ((unsigned) metrics_tag)
129   {
130   case HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER:
131   case HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER:
132   case HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP:
133   case HB_OT_METRICS_TAG_VERTICAL_ASCENDER:
134   case HB_OT_METRICS_TAG_VERTICAL_DESCENDER:
135   case HB_OT_METRICS_TAG_VERTICAL_LINE_GAP:           return _hb_ot_metrics_get_position_common (font, metrics_tag, position);
136 #ifndef HB_NO_VAR
137 #define GET_VAR hb_ot_metrics_get_variation (font, metrics_tag)
138 #else
139 #define GET_VAR 0
140 #endif
141 #define GET_METRIC_X(TABLE, ATTR) \
142   (face->table.TABLE->has_data () && \
143     (position && (*position = font->em_scalef_x (face->table.TABLE->ATTR + GET_VAR)), true))
144 #define GET_METRIC_Y(TABLE, ATTR) \
145   (face->table.TABLE->has_data () && \
146     (position && (*position = font->em_scalef_y (face->table.TABLE->ATTR + GET_VAR)), true))
147   case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_ASCENT:  return GET_METRIC_Y (OS2, usWinAscent);
148   case HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_DESCENT: return GET_METRIC_Y (OS2, usWinDescent);
149   case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE:       return GET_METRIC_Y (hhea, caretSlopeRise);
150   case HB_OT_METRICS_TAG_HORIZONTAL_CARET_RUN:        return GET_METRIC_X (hhea, caretSlopeRun);
151   case HB_OT_METRICS_TAG_HORIZONTAL_CARET_OFFSET:     return GET_METRIC_X (hhea, caretOffset);
152   case HB_OT_METRICS_TAG_VERTICAL_CARET_RISE:         return GET_METRIC_X (vhea, caretSlopeRise);
153   case HB_OT_METRICS_TAG_VERTICAL_CARET_RUN:          return GET_METRIC_Y (vhea, caretSlopeRun);
154   case HB_OT_METRICS_TAG_VERTICAL_CARET_OFFSET:       return GET_METRIC_Y (vhea, caretOffset);
155   case HB_OT_METRICS_TAG_X_HEIGHT:                    return GET_METRIC_Y (OS2->v2 (), sxHeight);
156   case HB_OT_METRICS_TAG_CAP_HEIGHT:                  return GET_METRIC_Y (OS2->v2 (), sCapHeight);
157   case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_SIZE:         return GET_METRIC_X (OS2, ySubscriptXSize);
158   case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_SIZE:         return GET_METRIC_Y (OS2, ySubscriptYSize);
159   case HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_OFFSET:       return GET_METRIC_X (OS2, ySubscriptXOffset);
160   case HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_OFFSET:       return GET_METRIC_Y (OS2, ySubscriptYOffset);
161   case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_SIZE:       return GET_METRIC_X (OS2, ySuperscriptXSize);
162   case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_SIZE:       return GET_METRIC_Y (OS2, ySuperscriptYSize);
163   case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_OFFSET:     return GET_METRIC_X (OS2, ySuperscriptXOffset);
164   case HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_OFFSET:     return GET_METRIC_Y (OS2, ySuperscriptYOffset);
165   case HB_OT_METRICS_TAG_STRIKEOUT_SIZE:              return GET_METRIC_Y (OS2, yStrikeoutSize);
166   case HB_OT_METRICS_TAG_STRIKEOUT_OFFSET:            return GET_METRIC_Y (OS2, yStrikeoutPosition);
167   case HB_OT_METRICS_TAG_UNDERLINE_SIZE:              return GET_METRIC_Y (post->table, underlineThickness);
168   case HB_OT_METRICS_TAG_UNDERLINE_OFFSET:            return GET_METRIC_Y (post->table, underlinePosition);
169 
170   /* Private tags */
171   case _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_OS2:    return GET_METRIC_Y (OS2, sTypoAscender);
172   case _HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER_HHEA:   return GET_METRIC_Y (hhea, ascender);
173   case _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_OS2:   return GET_METRIC_Y (OS2, sTypoDescender);
174   case _HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER_HHEA:  return GET_METRIC_Y (hhea, descender);
175   case _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_OS2:    return GET_METRIC_Y (OS2, sTypoLineGap);
176   case _HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP_HHEA:   return GET_METRIC_Y (hhea, lineGap);
177 #undef GET_METRIC_Y
178 #undef GET_METRIC_X
179 #undef GET_VAR
180   default:                                        return false;
181   }
182 }
183 
184 #ifndef HB_NO_VAR
185 /**
186  * hb_ot_metrics_get_variation:
187  * @font:
188  * @metrics_tag:
189  *
190  * Returns:
191  *
192  * Since: 2.6.0
193  **/
194 float
hb_ot_metrics_get_variation(hb_font_t * font,hb_ot_metrics_tag_t metrics_tag)195 hb_ot_metrics_get_variation (hb_font_t *font, hb_ot_metrics_tag_t metrics_tag)
196 {
197   return font->face->table.MVAR->get_var (metrics_tag, font->coords, font->num_coords);
198 }
199 
200 /**
201  * hb_ot_metrics_get_x_variation:
202  * @font:
203  * @metrics_tag:
204  *
205  * Returns:
206  *
207  * Since: 2.6.0
208  **/
209 hb_position_t
hb_ot_metrics_get_x_variation(hb_font_t * font,hb_ot_metrics_tag_t metrics_tag)210 hb_ot_metrics_get_x_variation (hb_font_t *font, hb_ot_metrics_tag_t metrics_tag)
211 {
212   return font->em_scalef_x (hb_ot_metrics_get_variation (font, metrics_tag));
213 }
214 
215 /**
216  * hb_ot_metrics_get_y_variation:
217  * @font:
218  * @metrics_tag:
219  *
220  * Returns:
221  *
222  * Since: 2.6.0
223  **/
224 hb_position_t
hb_ot_metrics_get_y_variation(hb_font_t * font,hb_ot_metrics_tag_t metrics_tag)225 hb_ot_metrics_get_y_variation (hb_font_t *font, hb_ot_metrics_tag_t metrics_tag)
226 {
227   return font->em_scalef_y (hb_ot_metrics_get_variation (font, metrics_tag));
228 }
229 #endif
230 
231 #endif
232